The Rise and Reign of the Mammals

I’ve wanted to see Dimetrodon ever since I was a little boy. My nose stuck in books about prehistoric animals, and there they were, these big scary creatures, with thick skulls and huge teeth, supporting that infamous sail on their back. They were even present in those packets of ‘dinosaur’ toys alongside pterodactyls and plesiosaurs. But Dimetrodon wasn’t a dinosaur. They scampered around on the Earth some 50 million years before the first dinosaurs even came to the scene. I knew this when I was that young, fairly round, blond-haired little boy. These animals were more closely related to us than they were to dinosaurs. And that has always fascinated me.

I saw Dimetrodon pop up in films. I remember sitting on the floor watching the old Journey to the Centre of the Earth (1959), on my own while my other siblings were running around outside, and there was Dimetrodon (well, not quite Dimetrodon, but an iguana with a sail strapped to it’s back, but back in the 80s, it was good enough for me!). I am not ashamed to say, I loved seeing Dimetrodon cause havoc in the underground tunnels more recently in Jurassic World: Dominion (2022). (Yes, I know, there probably weren’t even mosquitoes around 280 million years ago, but it is just a film, and it was awesome to see Dimetrodon!) It even makes an appearance in Fantasia (1940) where it is chased by a Tyrannosaurus rex!

My childhood fascination was finally quenched. I finally saw it. A beautiful mounted skeleton on display at the Field Museum, Chicago. And it was beautiful. Those sprawling legs, reminiscent of a crocodile. Those incredible, long thin bones on it’s back where flaps of skin would have attached to form the sail, like nothing alive today. And that big, powerful, thick skull, housing those different shaped teeth. I was mesmerised. My partner patiently let me take it in. She didn’t rush me, didn’t tell me to hurry. She stood by my side, taking it in too. She understood. This was an important skeleton. A skeleton of one of our very early mammal relatives.

The beautiful Dimetrodon skeleton on display at the Field Museum, Chicago. (Photo Jan Freedman)

Mammals are familiar to all of us. They are all around us. Cats, dogs, sheep, giraffes, bears, mice, elephants, whales, the list goes on. They are us: we are mammals too. The mammals we know today are very different to that Dimetrodon skeleton proudly on display at the Field Museum.

Our readers know how incredible mammals are, because the majority of our posts so far are about mammals. Familiar mammals like sabretooth cats and giant sloths, and weird mammals like the odd Toxodon and those weird chalicotheres. Huge mammals like the enormous Zygolophodon or Deinotherium with those odd downward pointing tusks, and small mammals like the horny gopher or the venomous shrew. But why so many mammals? Why so many incredibly different types of mammals, and why did some just look plain odd? And how the hell does Dimentrodon fit into the picture? Well, it’s a story that began around 325 million years ago. A story that Steve Brusatte brilliantly tells us in his new book, The Rise and Reign of the Mammals.

The Rise and Reign of the Mammals by Steve Brusatte (alliable here)

There are so many books about dinosaurs that come out every year, and as for mammals, well, there maybe one or two about cats or dogs. It is refreshing to see an accessible, engaging read about mammals, and more interestingly, how mammals as we know them today came to be. It’s not a simple linear progression to those fur balls we recognise today: the cast of characters was vast, like a grand Tolstoy saga. The fossil record of mammals dating back some 320 million years is a complicated, busy bush. There were groups of mammals that were spectacular but left no ancestors, there were others that were almost a mammal but not quite a mammal, and others still that beggared belief: a myriad of characters in an epic tale of luck and survival. Brusatte’s narrative throughout is seamless. He elegantly weaves together the most up-to-date research from his colleagues around the world to give us the story of mammal origins. Which, don’t forget, is essentially, our very own origins too: it shows how we are so closely linked to the rest of the animal kingdom.

It is such a fascinating history. Millions of years, across continents, and enigmatic fossils shedding light on a truly remarkable world long forgotten. There are things outside an animal’s control that have a lot to play on their evolution. And this is just one of the great things about Brusatte’s writing. He includes all the most recent research, not just the fossils themselves, but the continents, the climate, and other animals that shared the scene with early mammals, many of which were competitors. As climate changed, so did the vegetation, which in turn changed the way some mammals fed, some adapted well, others didn’t, resulting in whole groups of mammals disappearing forever. There’s also an incredible amount of luck: being in the right place at the right time; having the right little features to help them through a tough time. It’s fascinating to know that a single event (albeit an enormous extinction level event) some 66 million years ago cleared the way for mammals to roam freely, and expand into new niches and evolve into the most incredible range of shapes and sizes.

One of the (many) things I really liked in this book were the personal stories from his own fieldwork and experiences. It makes the book relevant, talking about real people making real discoveries (and not just old white dudes, but palaeontologists from all backgrounds, all over the world, studying early mammals and their ancestors). One moment you will be reading about dinosaur-eating mammals, the next you are whisked off to the Isle of Skye in Scotland. You almost get a sense of being there with Brusatte and teams of palaeontologists in the field. It a nice touch that flows perfectly with Brusatte’s narrative, and allows your brain to take a small break from some difficult terms, which he summarises again later for readers. I have read scientific papers about early mammals and their ancestors, and I can tell you, they are not the easiest of things to digest. Brusatte, however, writes so engagingly, you hardly even notice you are learning new terms, or names of long-vanished lineages. It’s obvious that he is very conscious of the reader, and that many people would be unaccustomed to many scientific terms, but he explains them clearly, and again later, as he wants us to make sure that we don’t get lost. Brusatte wants readers to enjoy this fascinating tale that took place over hundreds of millions of years.

And what about Dimetrodon? Our familiar scaly, sailed beast comes in fairly early in the story of mammals. Around 325 million years ago, there were small scaly animals, and they split into two groups: one that would eventually give rise to reptiles (diapsids), and the other group were the ancestors of all mammals alive today (synapsids). The group that gave rise to mammals evolved separately from the reptile group, evolving their own unique features. And this is the key – those features that we know as mammalian, like three ear bones, hair, secreting milk, did not all arise at once. Some features appeared and they were an advantage to those animals, and their descents would evolve more mammalian features. Dimetrodon was one of these animals. The world was changing 300 million years ago, with the damp coal forests shrinking, making way for drier land: a land better suited for animals that didn’t need water to lay their eggs. Enter Dimetrodon, which evolved from the synapsid (mammal) group of those scaly little critters. What’s amazing in Dimetrodon is the teeth. Reptile teeth are all the same shape, in mammals we have different teeth at the front, middle and back of our mouths. We all know we have incisors, canines, premolars and molars, and if you peer into the mouth of Dimetordon, you will see teeth that are pretty similar to ours, not reptilian, but teeth of different shapes and sizes: big canines, and different shaped teeth at the back compared to the front. And Dimetrodon wasn’t the only early synapsid around. There were other closely related beasts, like the chunky Bradysaurus, or those terrifying sabretooth killers, the gorgonopsids.

Another weird ancient mammal relative, Bradysarus, with it’s stocky body and teeny tiny head. On display at the Field Museum, Chicago.

This is, of course, only a snap-shot of the full story, which Brusatte describes with much more elegance than I. He describes such an huge range of creatures from incredible fossil discoveries, and how each feature that makes a mammal a mammal came to be over millions of years. But it doesn’t feel like you are reading a book full of facts, Brusatte vividly conjures up these ancient places where life, and the Earth itself, would have been very different. You get a glimpse into the past, 280 million years ago to when Dimetrodon and other incredible beasts were roaming the planet, or 40 million years ago where you are watching a tropical rainforest full of strangely familiar creatures. You can almost feel the heat, the moisture, and smell the air, from millions of years ago. Looking at mammals today, these prehistoric relatives look more like something from a fantasy than anything related to us.

You and I are today because of an uncountable myriad of chance happenings. A group of animals with hair, that fed their young milk, and had a mouthful of different shaped teeth, were lucky enough to survive. Evolution doesn’t lead to greatness. Animals alive today are not ‘better’ than animals 280 million years ago. Those animals back then were perfectly adapted to their environment. Dimetrodon and it’s kin, may look odd, ‘primitive’, but these were the top beasts of the time, and those teeth gave them an edge over other animals.

The evolution of mammals, of what we know as mammals today, took place over 325 million years. They didn’t just appear, but slowly features evolved, and these features and adaptations helped animals survive. This book is one of the finest, most accessible, I have read about the origins and evolution of mammals, and it’s one I will read again, if only to be transported back to a time when such incredible beasts walked the Earth. Incredible beasts, and extraordinary ancient relatives. We are here today because of creatures like Dimetrodon, the great-grandparents of us.

Written by Jan Freedman (@JanFreedman)

Further reading:

Brusatte, S. 2022. The Rise and Reign of the Mammals. Picador. [Book]

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Naming Nature

The naming of animals plants is not an easy task, yet it is probably one of the most important ones in science (even though there is little money available for it). We need to understand the unique biodiversity on our planet so we can protect it. Individual species have prevented construction work, protected wetlands, and even stopped a certain former President’s golf course from being built.  

Those scientists who name nature (taxonomists) are specialists in their field, and work on a specific group of organisms. When a new animal or plant is found, it is carefully, and meticulously, compared to others, which will help work out where it belongs on the tree of life. For example, a fly is a fly which is an insect, and a frog is a frog, which is an amphibian, so these are good starting points. Comparing to other groups and looking for similarities helps the taxonomists to see which species they are closely related to. It sounds complicated, and there are a lot of different steps (and Latin!), but if you understand the basics, it’s fairly simple. The system of taxonomy was devised by the Sweedish naturalist, Carolus Linnaeus, also known as Carl von Linné, (1707-1778). He wanted to organise animals and plants into groups based on their similarities, which indirectly shows how closely related species are.

A page from Linnaeus’ 10th Edtition of Systema Naturar in 1758. (Image Public Domain)

If we look at humans as an example, we can look at where we fit on the taxonomic tree. At the top, humans belong to the Kingdom Animalia (which includes all animals from worms to wombats). Next, humans are classed into the Phylum Chordata (all animals with a nerve chord running through their spines, also known as vertebrates). The next group is the Class, and humans belong in the Class Mammalia (all animals with fur or hair, secreting milk for their young, and have three ear bones). There are a lot of different types of mammals, and there are several groups (Orders) in the Class Mammalia, rats belong in the Order Rodentia which includes mice and shrews. Humans are placed in the Order Primates (animals that have a rotating shoulder joint and separate big toes and thumbs for holding onto things). Humans belong in the Family Hominidae, which includes all the great apes (chimpanzees, gorillas, and orangutans), primates that don’t have a tail. Within the Family Hominidae, humans belong to the Genus Homo, which is classified by walking on two legs and brain size. Finally, humans belong to the species sapiens, the individual species name for all humans, so our species is called Homo sapiens. This hierarchy of classification can be carried out for all organisms from jellyfish to whales.

Taxonomy can be taxing. Classification can be confusing. But it’s a way of understanding how all life on our beautiful planet is related, and how rich biodiversity is, and has been, and the job of the taxonomist is to unravel the mysteries of life.

Researchers use computer programs, which is known as cladistics, to work out the relationships between organisms. They input numerous characteristics, and the programme works out possible relationships. This example is looking at different species of moss. It can be done with anything, from ants to antelopes. (Image Public Domain)

For taxonomists studying life on Earth today, from the deepest rainforests to the cold, dark ocean floor, they have preserved specimens in museums they can use to work out where this creature of plant fits. They will compare the specimen they have found with many other species, and if it is new, then the specimen they describe is the type specimen of this new species (the specimen which defines that species). And with specimens in museums, there are a lot of features that can be compared, helping identify the organism, or seeing if it is a new species. Palaeontologists have a much more difficult time. Often all they have is a single bone, or a single tooth. But they do use the same techniques to identify the long dead animal. And an enormous number of different species have been identified and named increasing our understanding of life during the past.

Most of the time, palaeontologists will look at modern species and work out who their fossil is most closely related to. So cave lions, for example, are closely related to modern African lions (Panthera leo), so they are placed in the same Genus (Panthera) as a different species, Panthero spelaea. It gets more tricky with extinct beasts, because sometimes are no modern species closely related. Their entire line has vanished (Think of the weird Macrauchenia and Toxodon which were anomalies for decades, until research into their DNA finally unravelled their true relationships to other animals). The same principles still apply, and the scientists look characteristics in the bones to help identify closely related Families, and propose a new Genus and species. Or in the case of Dinosaurs for example, a completely new Order.

Sometimes things go the opposite way! An interesting, and little-known, beast was discovered in a cave in Brazil in the 1830s, by the Danish palaeontologist Peter Wilhelm Lund. A new Genus and new species to science. There were, at the time, no other animals like it. It was a dog, so the researched placed it in the Family Canidae, and gave a new Genus for it, Speothos venaticus. The Bush Dog. This was the type specimen for this species (the first specimen to be described and published, defining that species). It was until decades later that this extinct creature was found alive and well! It is very rare for an animal around to day to be scientifically named from fossils.

The living Bush Dog is a beautiful little animal. They are small, reaching just 12 inches at the shoulders, with beautiful soft brown fur, with orange tinges around their heads. It is actually divided into two sub-species: the South American Bush Dog (S. venaticus venaticus) and the Panamanian Bush Dog (S. venaticus panamensis). The two are similar enough to be the same species, but a few differences to separate them into sub-species.

The beautiful South American Bush Dog Speothos venaticus. (Image Public Domain)

They are rare little creatures, living in South and Central America, with habitat destruction is pushing them to the brink of extinction. Living in wetland areas, these incredible animals have webbed feet, and are extremely good swimmers. For such a small dog, they are pretty gutsy hunters. Mostly feeding on small rodents, they will sometimes attack capybaras or even the large flightless rea!

In 1984, another cave in Brazil was excavated and more fossils of Speothos were discovered. These fossils were larger than the living bush dog, and had slightly different molars, so a new species was described, Speothos pacivorus, the Pleistocene Bush Dog. The teeth show it was a carnivore, but as the soft parts of the body were not fossilised, we will never know if it had webbed feet. The Pleistocene Bush Dog is a mysterious beast.

It was a different environment for this ‘giant’. There were much larger creatures around, like mastodons and giant sloths, but these were much to big for this little predator, and it is more likely they preyed on smaller rodents, like pacas which were also found in the caves.. The Pleistocene Bush Dog would have faced competition from other, larger carnivores, such as the large canids Theriodictus and Protocyon, two much larger carnivores. Like the South American Bush Dog, this beast very likely created dens in burrows, to bring up their young and for safety against potential large predators.

Very little is known about the Pleistocene Bush Dog, and it is tempting to make assertions based on the living South American Bush Dog. But different species in the same Genus can have very different lifestyles and live in very different environments (think of the modern lion and the cave lion we mentioned earlier). We don’t actually know a lot about this captivating canid. More cave sites holding fossils will be able to tell us more about the habitat it lived in and even more about its lifestyle. For now, we have the Pleistocene Bush Dog. Enigmatic, yes. But for the time being, this is one more species added to the ever-growing list of incredible animals that have walked, or in this case, slightly waddled, on Earth.

Written by Jan Freedman (@JanFreedman)

Further reading:

Berta, A. (1984). ‘The Pleistocene Bush Dog, Speothos pacivorus (Canidae) from the Lago Santa Caves, Brazil’. Journal of Mammalogy. 65. pp.549-559. [Abstract only]

De Mello Beisiegel, B., and Zuercher, G. L. (2005). ‘Speothos venaticus’. Mammalian Species. 783. pp.1-6. [Abstract only]

Lagoa Santa Caves. In: Encyclopedic Dictionary of Archaeology. Springer. Cham.

Mayer, E. L., et al. ‘Taxonomic, biogeographic, and taphonomic reassessment of a large extinct species of paca from the Quaternary of Brazil.’ Acta Palaeontol. Pol.  61(4). pp.743-758. [Full article]

Nascimento, R., and Silveira, L. F. (2020). The fossil birds of Peter Lund. Zootaxa. 4743(4). [Abstract only]

Owens, P. (2001). ‘Speothos venaticus (South American Bush Dog)’. Digital Morphology. [Full article]

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The most (and least) read posts of 2021

2021. A second year into the pandemic. We really wish all of our readers a very safe, healthy and happy 2022. And we also would love to thank all of you for reading our blog posts over the year.

We have had some strange beasts, like the weird antelope that trumpeted, and some familiar beasts, like a detailed look at the evolutionary history of lions. We have loved writing about new creatures, adding to our list of 177 blog posts to date! Almost at the big 200!!

We have added a couple of things where readers can support us if they wish to.

  • You can also have a look at our Redbubble site, which offers mugs, T-shirts and even hoodies!! VIEW REDBUBBLE HERE.

As 2022 begins, we would like to share our top 5 blog posts of 2021, and also the 5 least read blog posts of 2021, because sometimes those underdogs are actually rather interesting!

The 5 least read blog posts of 2021

  1. Interview with a mammoth: If you could have a talk with a frozen mammoth, what would you ask it? Find out in this lovely post.
  2. From the bones of giants: Discover some of the beautiful sculptures made by humans over 30,000 years ago. Carved from the bones of giants, using just pieces of flint!
Beautiful swimming reindeer, carved out of mammoth tusk around 13,000 years old. (Image Public Domain)

3.Mini-beasts, giants and megafloods: What can insects tell us about the past? A surprising amount of reconstructing ancient environments is only possible thanks to these little critters.

4. Forever Young: Meet the little deer in Florida that never grew up.

5. Survivors: The incredible Saiga antelope, and how these are true survivors of the Ice Age.

The 5 most read blog posts of 2021

  1. Marching up the wrong tree: It is one of the most famous illustrations in science. But it’s wrong. Find out more why the March of Progress was created, and what’s wrong with it.
  2. The stuff of night-mares: The largest horse to have ever galloped on Earth. Need we say more?!

3. The Littlest Homo: In 2004 the world was introduced to the hobbit, a tiny species of human that lived on the island of Flores. Discover more about the work behind this discover, and more about this enigmatic species.

4. A very brief introduction to mammoths: With 10 different species of mammoths lolloping through time and the globe, there’s lots to explore!

5. An elk that wasn’t an elk: Find out about the largest species of deer, the Giant Deer!

Thank you to all our readers, old and new! We have really enjoyed writing these posts over the last year, and more posts will come in 2022!

We wish you all a very happy and very healthy 2022!

Rena (@JustRena), Ross (@DeepFriedDNA) and Jan (@JanFreedman). Follow us on Twitter  (@Twilightbeasts).

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Diminishing giants

Island dwarfism is perhaps one of the most beautiful examples of evolution through natural selection. Large animals that arrive on an island, evolve smaller sizes to survive on less food, and because there are fewer (if any) predators. (Similarly, small animals that are isolated on islands can get bigger, as we’ve seen with the dodo, the giant rabbit, and the giant duck.) The way species interact and are limited in island environments, is known as the island syndrome. This is where the form of a species along with the surrounding ecosystems, all play a part in how, and if, it survives with less resources available and new conditions to live in.

It does happen. And we have seen it already with many different species. The cute little hippos in the Mediterranean, tiny mammoths off the coast of California, and a weird goat from Mallorca, are just a few examples we have written about. These animals, and many more, adapted to island life, some in the most peculiar way. Isolated from populations on the mainland, they evolved in their own way to survive in a smaller space with new habitats and foods. It’s something quite remarkable when you think about it. Enormous mammoths evolving to a much smaller size over a few generations. Evolution is a pretty funky beast.

Another of these unique island creatures was the Cebu tamaraw, the extinct dwarf water buffalo (Bubalus cebuensis). Fossils of this small extinct water buffalo were discovered on the island of Cebu in the Philippines, in the 1950s, and it wasn’t for another 40 years that they were actually studied. This little creature patiently lay waiting in a museum. And Cebu tamaraw was small. Like, really small.  Buffalo are very big animals, and can be eye to eye with an adult human. Cebu tamaraw went through extreme size reduction, from a big buffalo to an animal about the size of an Alsatian! It’s the smallest example (so far) of island dwarfism in bovids.

Sometime, around 100,00 years ago the sea levels in the Philippines were much lower than today. Which meant that the hundreds of islands that we see in the Philippines today were either linked, or the water between them was much less. This is important, because this lower sea level allowed many animals from the mainland to wander, and sometimes take a short paddle to many of the islands. We do not have lots of information about when the Cebu tamaraw first evolved, because we have so few fossils found. They evolved from the Asian water buffalo, probably sometime around 100,000 years ago when the islands were more accessible. Similarly, we don’t know when they became extinct. Some researchers suggest this may have been relatively recently, just a few thousand years ago. And it is very likely that humans saw these miniature buffalos.

Today, around 170 species of mammals live in the Philippines, making it one of the richest places for mammals in the world. The huge number of islands just off the mainland, along with the changing sea levels, allowed many species of mammals to make their way to new environments and evolve separately from their mainland relatives. In all of this beautiful biodiversity is one close relative of the Cebu tamaraw, the tamaraw (Bubalus mindorensis). Slightly larger than it’s extinct relative, around the size of a sheep, the tamaraw is another dwarf water buffalo living on the island of Mindoro. It is currently endangered, with fewer than 450 individuals left, due to human habitat destruction and hunting.

We can learn a little about our extinct beast by looking at the life of the tamaraw that’s still alive today. They and once lived all across the island, from the coast to the top of the mountains, showing they were well adapted to live in a range of environments. With no predators (before humans arrived), the tamaraw was active in the day time, feeding on grasses and bamboo shoots. Today they are more restricted to thicker bushy vegetation and are active at night, which is a recent move by them to avoid humans. More fossils of the Cebu tamaraw from these islands will tell us al lot more about this enigmatic species, and how similar it was to it’s living relative.

More fossils will also reveal how diverse life was on these islands in the Philippenes. As recently as 2017, another species of dwarf buffalo was discovered to the south on the island of Sulawesi, in Indonesia. This long stretch of islands are not only rich in biodiversity today, but have been in the past. Full of amazing animals, and the more we discover, the more we can learn more about the richness of life on Earth.

Witten by Jan Freedman (@JanFreedman)

Further reading:

Croft, D. A. L., et al. 2006. Fossil remains of a new diminutive Bulbalus (Artiodactyla: Dovidae, Bovini) from Cebu island, Philippines. Journal of Mammalogy. 87. pp.1037-1051. [Full article]

Lomolino, M. V., et al. 2013. Of mice and mammoths: generality and antiquity of the island rule. Journal of Biogeography. 40. pp.1427-1439. [Full article]

Rozzi, R. 2017. A new extinct dwarfed buffalo from Sulawesi and the evolution of the subgenus Anoa: An interdisciplinary perspective. Quaternary Science Reviews. 157. pp.188-205. [Full article]

Rozzi, R., et al. 2020. Casual explanations for the evolution of ‘low gear’ locomotion in insular ruminants. Journal of Biogeography. DOI: 10:111/JBI.13942. [Full article] van der Geer, A., Lyras, G., and Drinia, H. 2013. Trends of body size evolution in the fossil record of insular Southeast Asia. Sage 2013. U

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Foolish dogs

In 1870 another species was wiped off the face of the Earth. The warrah, or the Falkland Islands wolf, was only known to science in 1792. Less than 100 years later it was gone. The last known induvial died in a zoo.

The first human settlement to the Falklands was in 1764, and has passed from French, to Spanish to British, to American control over the years. It was these early years that was the end of the only mammal on the Falklands. It’s scientific name, Dusicyon australis, literally means ‘the foolish dog of the south’. It was tame. It hadn’t seen humans before, so had no need to fear them. But this was disastrous. Sailors, and later settlers, would kill the warrah for meat and fur, and it wasn’t long before their numbers shrank.

The Falkland Islands wolf, Dusicyon australis. (Art John Gerrard Keulemans. Public Domain)

Charles Darwin visited the Falklands in 1834, and as always, made detailed observations of this usual animal. It was constrained to the Falklands, found nowhere else in South America. He notes how people would kill them easily “by holding a piece of meat in one hand, and in the other a knife ready to stick them.” And he foresaw their extinction: “Their numbers have rapidly decreased; they are already banished from that half of the island which lies to the eastward of the neck of land between St Salvador Bay and Berkeley Sound. Within a very few years after these islands shall have become regularly settled, in all probability this fox will be classed with the dodo.”

We don’t know how the warrah arrived on the Falklands, which is 300 miles from the South American mainland. But we do know that its ancestor, Dusicyon avus lived in South America.

Dusicyon avus were widespread across South America and fossils have been found in Brazil, Uruguay, Argentina, Chile, and Patagonia. Although called a wolf because of the Falkland Islands wolf, both species are actually closer to foxes than to wolves. DNA research into the fossils of D. avus showed it to be closely related to the odd, leggy, Manned Wolf (which again the name is misleading, as it is neither a wolf nor a fox!).

About the size of a small Alsatian, D. avus were very common in the Late Pleistocene and Holocene. We can find out a lot about how they would have lived by looking at their bones. Analysis of the skull shape suggests that they may have filled the same ecological niche as jackals do today.  It was likely a scavenger, whilst hunting smaller prey. We don’t know if they shared a similar life to jackals, which live as monogamous pairs, or more like large family packs similar to wild dogs. With shorter legs than wild dogs, it is more likely they were not long-distance runners chasing prey down. But they were very successful, and ranged over most of grass plains of South America, which makes their extinction very strange.

The small fox wolf, Dusicyon avus from South America.

It was thought that they became extinct around 3000 years ago, which is late in comparison to other extinctions in South America (between 12,000 and 10,000 years ago). Recent radiocarbon dating suggests they became extinct as recently as 400 years ago. This is extremely recent. And quite sudden. Some researchers have suggested that a more humid climate may have changed the available prey for D. avus, but these were more likely to be opportunistic predators, so it seems very unlikely. They lived in open grass environments, across varying climates, so a change in humidity wouldn’t have affected them much. Humans did have a relationship with these animals. Several burial sites contain bones of D. avus, with at least one potentially being intentionally buried: suggesting that it was a tamed animal (people have tamed wild foxes across the world for centuries). Their disappearance does coincide with Europeans settling in the Americas, and domestic dogs, and increased human presence could have just added that extra pressure.

This isn’t a well-known beast. Giant sloths and sabre tooth cats get a lot of the attention when it comes to Pleistocene animals from South America. But this little fox-wolf was a part of their ecosystem too. And they shouldn’t be forgotten. There are some who, like the thylacine, believe that D. avus is still out there. Sadly, I don’t think so. Sadly, these wonderful little animals are one in a long list which are gone from our beautiful planet forever.

Written by Jan Freedman (@JanFreedman)

Further reading:

Austin, J. J., et al. 2013. The origins of the enigmatic Falkland Islands wolf. Nature Communications. 4 (1552). [Full article]

Hamley, K M., et al. 2021. Evidence of prehistoric human activity in the Falkland Islands. Science Advances. 7 (44). [Full article]

Prates, L. 2015. Crossing the boundary between humans and animals: the extinct fox Dusicyon avus from hunter-gatherer mortuary context in Patagonia (Argentina). Antiquity. 88 (342). pp.1201-1212. [Abstract only]

Meloro, C., et al. 2017. Evolutionary ecomorphology of the Falkland Island wolf Dusicyon austalis. Mammal Review. [Abstract only]

Prevosti, F. J., and Martin, F. M. 2013. Paleoecology of the mammalian predator guild of Southern Patagonia during the latest Pleistocene: Ecomorphology, stable isotopes and taphonomy. Quaternary International. 305. pp.74-84. [Abstract only]

Prevosti, F. J., et al. 2015. Extinctions in near time: new radiocarbon dates point to a very recent disappearance of the South American fox, Dusicyon avus (Carnivora: Canidae). Journal of the Linnean Society. 116 (3). pp.704-720. [Full article]

Slater, G. J. 2009. Evolutionary history of the Falklands wolf. Current Biology. 19. pp.937–938. [Full article]

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When time disappears

Time. It’s a funny thing. We are aware of time. We watch time. Sat on a long train journey, or in a very tedious meeting, and time seems to last for ever: the seconds tick by slowly. There are other moments when time just seems to vanish. An afternoon with your little ones can be over in an instant. Hours spent with the one you love can seem like minutes. That’s the strange thing about time. It can warp. It can appear longer or shorter even though the same amount of time has passed. I guess you can measure your enjoyment of something through the passing of time.

For me there are a couple of things that make time just vanish. One is being out in nature. Away from emails, away from people. Watching the insects trundle or hover is like being transported to a different world. Sitting watching little blue tits or goldcrests dart back and forth is exhilarating. And I could sit and watch a heron on a river bank all day long. Here, nothing else exists, not even time. It is just myself and the beautiful world.

The gorgeous Grey Heron (Ardea cinera). (Photo Andreas Trepte. Public Domain)

Herons are gorgeous birds, and so wonderful to see. Their long stilt-like legs moving ever so slowly to get in the best position. And once in position, it waits. Not a sound. Not a movement. The legs don’t even twitch. And then you see it’s body slowly move forwards and down. The long neck arched back and poised. Ready. And you sit up and watch intensely. The heron strikes so fast it makes you gasp. It lifts its head with a fish, or a frog. It’s quite something to witness. Watching these birds is just mesmerizingly beautiful.

The heron that hypnotises me, is the Grey Heron (Ardea cinerea), a common sighting along rivers, estuaries and lakes in the UK. They are fairly big birds too, up to a meter tall. But they are not the tallest. The Goliath Heron (great name!), is over a meter and a half tall, as tall as many adults. Even this giant wasn’t the largest heron to have stalked the shallows. The enormous Bennu Heron (Ardea bennuides) reached over two meters tall, and would have been able to look a human in the eye.

The huge Bennu Heron next to a 1.8m tall human.

The Bennu Heron is an enigmatic bird. Fossils are only known from the Umm Al-Nar excavations, near Abu Dhabi, in the United Arab Emirates. This site dates to the Bronze Age (around 4,500 years ago) and excavations revealed human remains and artefacts, along with several animals species, including the first evidence of domesticated camels, and the giant Bennu Heron. It’s an important archaeological site, and was the first site to be excavated in the United Arab Emirates, just 50 years ago. Several new sites discovered over the following decades showed that the Umm Al-Nar culture was fairly widespread along the coast and inland around 4,500 years ago.

Umm Al-Nar was a well established settlement for several hundred years, with a large number of houses, some of which were big enough for congregations of people inside. The site also has around 49 cairns, or tombs; stones stacked into dome-like shapes. Human remains and animal bones have been found inside these tombs, as well as well-preserved fragile pottery vessels, still with the painted decorations on them. This wasn’t just a little village. The people here were trading with other settlements around the United Arab Emirates, and even further afield.

How does our giant heron fit in to this amazing site? Large numbers of animal bones were excavated near the houses, including camels, dugongs, turtles, and several bird species, including the Bennu Heron. There is no evidence that the heron was eaten by the villagers: no cut marks, no burns on the bones. It is more than likely that they are the remains of birds which died naturally, and accumulated with other species.

Today Umm Al-Nar is connected to the mainland due to dredging and land reclamation. 4,500 years ago, however, it was a small island, surrounded by shallow waters and marshlands. This was the environment for the Bennu Heron. Those long legs perfect for silently wading through the shallows. Herons today will eat anything including fish, small mammals, reptiles and amphibians. They are not picky. The Bennu Heron was probably similar, a large predator, still, motionless, waiting and grabbing any unfortunate animal it could.

The Bennu Heron may have been more widespread than just Arabia. Bennu was god in Ancient Egypt linked to the sun and rebirth. This god was a giant heron. Ancient Egyptian writings show this god to be the same size as the Bennu Heron found at Umm Al-Nar. And we do know that the Ancient Egyptians based their gods on animals they saw around them. Some archaeologists and historians think that the Bennu Heron was the inspiration of Bennu the god (the name Bennu Heron was given to it because of it’s similarity with the Bennu deity).

Ancient Egyptian drawing on papyrus of the Bunnu God. (Image Public Domain)

More fossils will help us to understand this animal much better. We don’t currently know how long this gigantic bird was on Earth for, or when it became extinct, or even why. We don’t know whether they nested in trees (like some heron species do today). There’s an awful lot we don’t know. But we do that humans did see it. Perhaps they too sat and watched the Bennu Heron. Maybe they lost all track of time as they watched this colossal beauty in the marshlands hunting for food.

Written by Jan Freedman (@JanFreedman)

Further reading:

Al Tikriti, W. Y. Umm An-nar, an ancient capital of Abu Dhabi: distribution of a culture and the current state of the site. In Fifty Years of Emirates Archaeology. Chapter 8. Motivate Publishing. [Full article]

Hellyer, P. 1998. The relevance to Archaeology to coastal zone management. Tribulus. 8 (1). pp.26-28. [Full article]

Hoch, E. 1977. Reflections on prehistoric life at Umm An-Nar (Trucial Oman) based on faunal remains from the third millennium BC. In M. Taddei (Ed). South Asian Archaeology 1977. Fourth International Conference of the Association of South Asian Archaeologists in Western Europe. pp.589-638.

Krienitz, L. 2018. The firebird Phoenix. In Lesser Flamingos. Springer, Berlin, Heidelberg. [Abstract ony]

Potts, D. T. 2001. Before the Emirates: and archaeological and historical account of developments in the region c. 5000BC to 676 AD. In Al Abed, I., & Hellyer, P. (Eds). The United Arab Emirates: A new Perspective. London, Trident Press. [Full article]

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The bellowing antelope

Locked within Rusinga Island are secrets from the past. Secrets of life long gone trapped in the ash of an ancient volcano. It is sat in the north east of Africa’s largest lake known by locals as Nam Lolwe, Nnalubaale, and Nyanza, and was called Lake Victoria by the British in 1858. Fossils on Rusinga Island have been known by locals for many centuries, including the remains of extinct crocodiles, antelopes, and ancient primates.

A gold prospector discovered the first primate fossil, a small jaw bone, on the island in 1909. But it wasn’t until expeditions in the 1930s and 1940s by Louis and Mary Leakey and their team that put this and other fossils on the world stage. Louis and colleagues found several teeth and bones from primates in the 1930s, which they named Proconsul. In 1948, Mary found the first fossil skull of this ancient ape. Originally seen as an ancient link between humans and apes, the media around the world flocked to see this beautiful specimen, which set up the Leakeys for lots of generous funding opportunities for the future.

Illustration of Proconsul. (Art by Maurico Anton. Public Domain)

Today there are four known species of Proconsul, which lived between 23 and 14 million years ago. It was not an ape-human ancestor, or the ancestor of chimpanzees, as was once thought. Lacking a tail, Proconsul may be one of the earliest ancestors of apes, or it may just be an evolutionary dead end, leaving no descendants.

It wasn’t just the ecosystem of 23 million years ago that Rusinga Island has revealed. Life in the Pleistocene, the time of the Twilight Beasts, was also preserved in younger rocks. Fossils of turtles, extinct antelopes (Damaliscus hypsodont), extinct pigs (Kolochoerus) and many other extinct species of bovids have been found. Including one very odd species, Rusingoryx atopocranion, the bellowing antelope.

The strange looking antelope Rusingoryx. It was slightly shorter than a human, and had one of the strangest mammal skulls known. (Illustration by Sophia Anderson. Reproduced with permission.)

Rusingoryx is a relative newcomer to the mélange of Pleistocene beasts. Found on a site, appropriately named Bovid Hill, the first fossils were named in 1984. It was almost 20 more years until more excavations found many more specimens, some of which showed signs of being butchered by humans. Closely related to the wildebeest, this animal was a much smaller antelope, with some peculiar features. (A quick side note on antelopes and bovids. Antelopes may be more familiar as those fast, springy, deer like animals seen on nature programmes. They are however a kind of catch-all name for animals in the Family Bovidae that are not cows, sheep, or goats. So wildebeests are called antelopes despite looking more like cows or bison, because of their anatomy. And our strange beast, Rusingoryx, is also an antelope.)

Although Rusingoryx has been found at other sites in Kenya, the abundance of fossils at Bovid Hill have given us a lot of information about this unusual bellowing beast. The skull, well the skull was weird. With a pointy nose, it has a feature not seen in any other mammal: a large empty nasal passage. The rest of the skeleton shows that this antelope was fast and well adapted to running in open landscapes to flee from predators.

So many individuals have been found at Bovid Hill, that they may have been from a single herd, which were all buried very quickly in a shallow river channel around 65,000 years ago. But this herd may not have died naturally. There are stone tools in the same deposits, and cut marks on the bones, showing that this may have been a kill site for Homo sapiens. How did humans kill such a large group of fast herbivores isn’t known, but it does show that they did hunt them and trap them, perhaps in water to slow them down.

In the past, Rusinga Island was not an island, but joined to the mainland of Kenya until the lake subsided over time, flooding more of the land until Rusinga was seperated. All these herds of different species were roaming and moving across the plains of Kenya. The adaptations of Rusingoryx and other species show that the plains of Kenya were open grasslands, different from the drier grasslands in Kenya today. This may be the reason for their extinction. These unique creatures were well adapted to the open plains, but their teeth were not adapted to drier grasses. Although they were hunted by humans, it may have been the changing environment that caused Rusingoryx to vanish.

A scan of the skull of Rusingoryx. The scan revealed that the nasal passage (coloured in yellow) and the sinuses (coloured in green) were completely empty and would have been filled with air. (Image from O’Brien, 2016)

And that weird nasal passage full of air? Well, it was quite bizarre and unlike anything seen for 80 million years. It was hollow, and some researchers suggest that it may have been used to make deep bellows, similar to hadrosaur dinosaurs. This is an example of convergent evolution, where two completely different species evolved similar traits independently. Just like hadrosaurs, Rusingoryx may have used their nasal dome for vocalisation to communicate in the herd, or to attract a mate. It would have been amazing to hear the low bellow of this beast on the plains of Kenya, and our species did. Sadly, they became extinct sometime around 10,000 years ago, so like the trumpeting dinosaurs, we can only imagine the sounds they made.   

Written by Jan Freedman (@JanFreedman)

Further reading

Bonnefille, R., Roeland, J.C., and Guiot, J. 1990. Temperature and rainfall estimates for the past 40,000 years in equatorial Africa. Nature 346. pp.347–349. [Abstract only]

Faith, J. T., et al. 2011. Taxonomic status and paleoecology of Rusingotyx atopocranion (Mammalia, Artiodactyla), and extinct Pleistocene bovice from Rusinga Island, Kenya. Quaternary Research. 75. 3. pp.697-707. [Abstract only]

Faith, J. T., et al. 2012. New perspectives on middle Pleistocene change in the large mammal faunas of East Africa: Damaliscus hypsodont sp. nov. (Mammalia Artiodactyla) from Lainyamok, Kenya. Palaeogeography, Palaeoclimatology, Palaeocology. 361-362. pp.84-93. [Full article]

Faith, J. T., et al. 2014. Biogeographic and Evolutionary implications of an extinct Late Pleistocene impala from the Lake Victoria Basin, Kenya. Journal of Mammal Evolution. 21. Pp.213-222. [Full article]

O’Brien, H. D., et al. 2016. Unexpected Convergent Evolution of Nasal Domes between Pleistocene Bovids and Cretaceous Hadrosaur Dinosaurs. Current Biology. [Full article]

Jenkins, K. E., et al. 2017. Evaluating the potential for tactical hunting in the MIDDLE Stone Age: Insights from a bonebed of the extinct bovid, Rusingoryx atopocranion. Journal of Human Evolution. 108. pp.72-91. [Full article]

Klein, R. G., and Cruz-Uribe, K. 1991. The bovids from Elandsfontein, South Africa, and their implications for the age, palaeoenvironment, and origins of the site. African Archaeological Review. 9. pp.21–79. [Full article]

Kovarovic, K., et al. 2021. Ecomorphology and ecology of the grassland specialist, Rusingoryx atopocranion (Artiodactyla: Bocidae), from the late Pleistocene of western Kenya. Quaternary Research. 101. pp.187-204. [Full article]

O’Brien, H. D., et al. 2016. Unexpected convergent evolution of nasal domes between Pleistocene bovids and Cretaceous hadrosaur dinosaurs. Current Biology. 26 (4). pp.503-508. [Full article]

Pickford, M., Thomas, H., 1984. An aberrant new bovid (Mammalia) in subrecent deposits from Rusinga Island, Kenya. Proceedings of the Koninjlijke Nederlandsche Akademie van Wettenschappen B87, pp.441–452. [Abstract only]

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The largest of the rodents

Guinea pigs are common pets around the world, with over one million of these furry, or sometimes naked, little rodents being cared for by people. They are relatively easy to look after, and pretty cute too. My daughter likes to watch guinea pigs on You Tube – she finds it relaxing. I was flabbergasted to see that some videos of guinea pigs just sitting or eating, have over 10 million views! People do like the cuteness of these relatively large rodents. Capybaras, the largest living rodent and close relative to the guinea pig, have the same cuteness appeal. Their sleepy looking eyes and docile nature, along with their large size win the hearts of whoever sees them.

Endemic to South America, capybara are very large rodents, about the size of a fairly large dog, only much rounder and shorter legs. But they are not the biggest rodents to have waddled on Earth.  This crown currently belongs to the enormous rodent Josephoartigasia monesi, which was about as large as a cow!

The massive rodent, Josephoartigasia monesi from South America.

This enormous beast was found in rocks dating between 4 and 2 million years old, and has only relatively recently described in 2008. (Another example of the importance of museum collections, the skull was in the National Museum of Natural History in Uruguay, after being excavated in 1986.) This skull, missing the lower jaw, is a whopping half a meter long. Rodents are not this big! The capybara’s is less than a third this length. For something so large, how do we know it’s a rodent and not something else? It’s the teeth that give it away.

Teeth are very diagnostic in mammals. Different groups have their own unique shapes, which are a little modified within species. All the species belonging to the Order Carnivora, for example, have large conical canines, flat sharp incisors, large sharp premolars, and slicing molars. All groups of carnivores share these traits, although within the group, different species will have slightly modified versions depending on their dietary needs. (The European sabretooth cat, Homotherium, for example, has serrations on its incisors which is like a hot knife through butter. Only the butter is flesh.) Rodents on the other hand, belong to the Order Rodentia, and have four very large incisors (two on the top, two on the bottom), which grow continuously throughout their lives. Most species have no canine or premolars, with a gap between the incisors and the tough ridged, plated molars. The teeth of J. monesi are the teeth of a rodent.

So far, we only have the skull. But this can still give us a lot of information, including its size and who it is related to. The bone structures in the skull of J. monesi, along with the premolars and teeth, show it belongs to the Family of rodents called Dinomyidae. Although once a very diverse group, appearing around 30 million years ago, today there is only one living species, the pacarana, which is about the size of a cat. Various measurements and analysis of the skull put J. monesi in the range of 1200kg, which is about the same as a cow or bison.

The last surviving member of the Dinomyidae, the lovely pacarana (Dinomys branickii). (Photo Benjamin Frable. Public Domain)

The skull and teeth also provide clues about the animals feeding habits, and the environment it lived in. The bones which attached the cheek muscles are quite slender, and this hints that the muscles were relatively small for such a big animal. This along with the relatively small grinding teeth suggest that the diet was softer vegetation and possibly fruits. They may have eaten aquatic plants, as other fossils found with J. monesi are typical of a delta type environment with nearby forests, similar to the environment of the capybara today. The large incisors have been compared to the tusks of elephants, which may have been used for digging or scraping for food, and even fighting for defence or for females.

There is still a lot more to learn about this huge beast, and when more fossils of the skeleton are found, they will give even more information. The rocks the skull was found in age to between 4 and 2 million years ago, so more fossils will also give us a better time range for this species and give us clues to why it became extinct. The skull was found alongside other fossils, such as giant sloths and sabretooth cats. Sabre tooth cats only made their way to South America around 2.7 million years ago. Before then, J. monesi would have been adapted to the natural predators of South America, which was an isolated landmass. With North and South America joining around 2.7 million years ago by underwater volcanoes and sediment, this meant that animals from both landmasses could move between the two. New predators, like sabre tooth cats would have seen these giants as an easy meal. That’s one possibility. The climate was also becoming a little cooler around this time, and we don’t know if this had an impact on our cow-sized rodent.

It would be quite something to see this enormous creature wallowing in the shallow waters of a river in South America. With the rustling leaves of a nearby tree as a giant sloth slowly moves past. And perhaps a low rumbling of a sabretooth cat nearby, heard but not seen. The mammals of South America at the beginning of the Pleistocene were part of a truly unique landscape.

Written by Jan Freedman (@JanFreedman)

Further reading:

Blanco, R. E. 2008. The uncertainties of the largest fossil rodent. Proceedings of the Royal Society. 275. pp.1957–1958. [Full article]

Blanco, R. E., Rinderknecht, A., & Lecuona, G. 2012. The bite force of the largest fossil rodent (Hystricognathi, Caviomorpha, Dino[1]myidae). Lethaia 45. pp.157–163. [Full article]

Cox, P. G., Rinderknecht, A., and Blanco, R. E. 2015. Predicting bite force and cranial biomechanics in the largest fossil rodent using finite element analysis. Journal of Anatomy. 226. pp.215-223. [Abstract only]

Cox, P. G., Rinderknecht, A., and Blanco, R. E. 2015. Masticatory biomechanics of the largest fossil rodent. The FASEB Journal.

Fields W.R. 1957. Hystricomorph rodents from the Late Miocene of Colombia, South America. Univ. Calif. Publ. Geol. Sci. 32. pp.273–404. [Full article]

Millien, V. 2008. The largest among the smallest: the body mass of the giant rodent Josephoartigasia monesi. Proceedings of the Royal Society. 275 (1646). pp.1953-1955. [Full article]

Mones A. 2007. Josephoartigasia, Nuevo nombre para Artigasia Francis & Mones, 1966 (Rodentia, Dinomyidae), non Artigasia Christie, 1934 (Nematoda, Thelastomatidae) Comun. Paleontol. Mus. Hist. Nat. Montevideo. 36. pp.213–214.

Rinderknecht, A., & Blanco, R. E. 2008. The largest fossil rodent. Proceedings of the Royal Society. 275 (1637). pp.923-928. [Full article]

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The littlest Homo

The field of human evolution is fascinating. New finds are changing our knowledge each year as more and more incredible discoveries are made. The 21st century has really opened our eyes to how wonderful and diverse our ancient relatives were. Ancient cave art in Indonesia, Neanderthal art, and new fossils pushing back the date of the origin of our own species. As well as these amazing insights to how our relatives lived, several new species have been discovered too! It really is an exciting time for palaeoanthropology.

I am regularly reminded of how much we are discovering about our own evolution and that of our relatives as my thumb scrolls through my phone on Twitter. I see some amazing facts. Old historical discoveries. New exciting discoveries. And one of my favourite Twitter science people is Dr Paige Madison. Every day she tweets about the history of science, the curious characters, and anthropology amazingness. And every day I learn something new. The 21st century is showing that our past is more complicated that we thought. Groups from one species travelled out of Africa, often at different times. New tools, new art, are shining a light on how some of ancestors lived. There is no simple narrative to our own evolutionary history.

One of the most astounding discoveries this century, well the most astonishing in the whole history of palaeoanthropology, is the discovery of a very small species of human on the Island of Flores: Homo floresiensis. And it was a very small species. Reaching just over a meter tall, these were real hobbits. Our ancient relatives, the Australopithecines, were small (the famous skeleton of Lucy was about the same size). But over time hominins have grown taller, and that’s what makes this species such a curious find: it wasn’t a species from 3 million years ago, it was around until fairly recently.  I’ve been itching to write about this little hominin for a long time, so I contacted Paige. Having recently finished her PhD in historical anthropology examining the history of Neanderthals, Australopithecines, and the hobbit, she was the perfect person to talk to about these little humans. She has studied the history of their discovery. Spent months working at the site. She has lived these enigmatic humans for over three years.

Yours truly next to a replica skeleton of Homo floresiensis. On display at the Natural History Museum, London.

The first fossils of H. floresiensis were excavated in 2003. “This was such a huge discovery,” Paige says from her desk as we talk through our laptops. Behind her, a cast of the skull of H. floresiensis sits. “The findings were published in 2004. The scientists didn’t expect such a huge response from the media. Phones were ringing every day.” The world went crazy wild for this new find. A new human species that was only a little over a meter tall. These were fossils of adults, not juveniles. It wasn’t long before it was nicknamed the hobbit. “It’s quite funny really. The team nicknamed it the hobbit before it was published, and even joked about naming the new species Homo hobbitus!”

I wanted to know more about this mysterious species.

Fossils were found in the cave of Liang Bua Cave on the Indonesian Island of Flores. “It’s beautiful.” Paige tells me, reminiscing. She has spent many weeks working in the cave. “It is quite high up, about 500 meters above sea level. When you are inside it’s cool. So perfectly cool, it should be the marker for how offices should set their temperatures. The closest translation for Liang Bua is probably ‘cool cave’. Because it is so cool, people can work in there easily in just a T-shirt or a light jacket. There are currently four pits that are being excavated, each 3 meters by 3 meters. And we have 45 people excavating.”

I try to visualise it. Liang Bua is a very large cave, and the excavation is meticulous. It’s tempting to just go in and dig. But archaeology requires a lot of patience. A grid is chosen, and then, slowly each layer is excavated. Everything is recorded as the archaeologists work. “One visitor said to me ‘that looks terribly boring’ as they watched people excavating!” Paige joked as we talked about the excavation. The Wae Racang River is close by, and this probably gave the cave the really nice layers that they have found: each time it flooded, sediment was gently pushed into the cave, building up over time. “The layers in the cave are really clear. The only trouble is, there are interesting things in the top layers, which are younger, so we have to be so patient to get to the older layers below where H. floresiensis is found, which we call the hobbit layers. With the sediment around 20 meters thick, it takes a long time to reach the oldest layers at the bottom. There is very likely decades more research in this one site alone. We are training locals how to excavate and record and study the finds, so that the fossils in their country can be studied by the next generation of Indonesian scientists.”

Liang Bua is a large cave site, with a large number of workers excavating the sediment. Visitors to the caves are normal, with tourists coming to see the home of the hobbits. (Photo Liang Bua team).

Working in a museum, I am well aware of Europeans taking fossils, and animals and plants, for their own research in the past, so I was really happy to hear the collaborative work the team at Liang Bua are doing.  Paige could sense this. “This isn’t actually new. Many of the local excavators have been there a long time. Some for decades. The research itself has long been led by Indonesians, just partnered with foreign scientists because they are able to bring in the funding. Thomas Sutikna is a great example, he has been directing the excavations since the early 2000s and is himself the 2nd generation of Indonesian archaeologists to do so (his advisor, Raden Pandji Soejono was the first, emerging as an archaeologist after Indonesia won its independence in 1949). Sutikna is really leading the charge of training the next generation of Indonesian scientists, along with Matt Tocheri who has two Indonesian archaeologists completing masters degrees at his university in Canada right now.” All too often we assume that the people behind the research are European or American. It’s so important to know everyone involved in the science behind these discoveries.

The meticulous work of the archaeologists painstakingly excavating with incredible patience. The layers of the cave sediment can be seen in the background. (Photo Liang Bua team)

There have been relatively few fossils of H. floresiensis found so far: a very well-preserved skull, a jawbone, and fragmentary bones of the skeleton. All in all we have the fossils of just seven individuals from this species. I assumed that this unique little human evolved from Homo erectus, a human ancestor who was one of the first species to travel outside Africa. H. erectus was incredible successful, living from around 2 million years ago until just 100,000 years ago. It was a widespread species too, and fossils have been found across Europe and Asia. And H. erectus even made it to some islands. If they got to Flores, that population could have evolved into a smaller size. We have seen this before with dwarf mammoths, and dwarf hippos: large species evolve to be smaller on islands, as an adaptation to less food supplies.

I talk a little too quickly about dwarf mammoths. Paige patiently lets me finish, and with a mischievous smile, she says that’s one theory. She picks up her cast of the skull behind her. “The skull of the little floresiensis does share similarities to erectus. When I first saw the skull, I noticed how thick the bone was, just like erectus. It is possible that it was the ancestor. But there is another theory. The skull does share traits from erectus, but the skeleton doesn’t look anything like it. Bones do change when animals are reduced in size, but the skeleton of floresiensis shows too many changes. Too many to make sense that erectus was the ancestor. There are suggestions that the ancestor may from an Australopithecus species.” I nearly spit out my tea. There were several species of Australopithecus, very early relatives to us, dating from around 4 million years ago to around 1.6 million years ago. And no fossils of any Australopithecus species have been found outside of Africa. If this theory is right, that is big. Really big. After listening to me getting too excited, she tantalisingly adds, “If an Australopithecus, or a very early Homo, species was the ancestor, these were already small hominins, so they wouldn’t have shrunk in size. It is possible. It’s just that we haven’t found them yet on the mainland of Asia. Yet.”

A cast of the skull of Homo floresiensis on display at the Cantonal Museum of Geology, Switzerland. (Photo Public Domain).

The site is incredible, and the painstaking work to excavate everything so meticulously is remarkable. Excavations have also found lots of stone tools in the deepest layers (the hobbit layers), so it looks like the hobbit was here for quite a while. “It’s quite amazing,” she talks with excitement, her hands waving, “we have stone tools at the deepest levels, and all the way up until when they disappear. It looks like Liang Bua was a regular camp site for this human.” Even though I am sitting in my little home office in England, and Paige is in hers in Denmark, I can see the passion as she speaks. “The oldest layers are about 200,000 years old, and until 100,000 years ago we find just stone tools, no fossils of floresiensis. Then we find fossils from about 100,000 years ago until around 46,000 years ago. That’s when they vanish from this site. And in the layers above we find evidence of our species, Homo sapiens. Interestingly there is no evidence of fire in the deeper layers relating to the hobbit, but there is evidence of fire in the layers where we find H. sapiens.”

The animals living alongside H. floresiensis add to the mystery of this island in the past. Komodo dragons lived here, and still do, although they have now moved to more coastal areas. There were stranger things too, more fitting for a fantasy film than reality. Giant storks, over two meters tall, giant vultures, giant rats the size of a cat, and pygmy elephants. Evolution on Flores was its own unique laboratory. And the world these hobbits lived in was unlike anything today. “There were a lot of rat bones, making up about 78% of the fossils found, and included giant rats. That’s a big percentage. This is really good for us because we can work out the environment with the fossils. The rats from the older layers near the bottom show a more open environment with less forest. Then around 46,000 years ago we see just two species instead of several, and these two species are more at home in a forest environment, similar to what Flores is like today.”

Something happened 46,000 years ago. No H. floresiensis have been found after that time. All the mega-fauna, apart from the Komodo dragons, disappear as well. And the rat species change too. And then above this date, we see our species in the cave. Coincidence? Perhaps it is. “It’s not always as clear as we would like. Around 46,000 years ago we find a layer of ash. It’s really thick, showing that there was a very big volcanic eruption and it must have been close by. Then above the ash layer we find no hobbits and find our species instead. But this doesn’t mean the hobbits went extinct at that time. Like the Komodo dragon, they could have just moved somewhere else.” The timing of extinction is always contentious. Just because we don’t find fossils of a species above a certain point, doesn’t mean that is when they became extinct. Chatting about the fossil record and lack of fossils, Paige smiles. “At the moment Liang Bua is the only site on Flores with fossils of floresiensis. We are looking at other places where there could potentially be fossils. And these could tell us so much more about this species. It is an incredible species, and we have only scraped the surface.”

Archaeologist, Dr Thomas Sutikna, examining the stragigraphical layers of the cave. Note the thick grey layer behind him. This is the ash from the volcanic eruption around 46,000 years ago. (Photo Dr Hanneke Meijer)

There’s a twist in the tale. In 2007, some fossils were found in Callao Cave in Luzon, in the Philippines. Originally described as belonging to modern humans, more fossils were found, showing another diminutive hominin. The fossils of this new species, Homo luzonensis, date to around 50,000 years ago, and evidence in the cave suggests they may have been there as early as 770,000 years ago. “For an early human species to cross the seas around Indonesia would have been very difficult. The currents are so strong. It might be that luzonensis offers some new clues as to how the hobbits got to Flores. There are a lot of islands in the area, and at the minute not a lot of exploring for fossil sites. This is a really exciting time for us and luzonensis could offer hints at ancient routes.”

Homo floresiensis is an incredible discovery. It shows us that our family tree is a lot more bushy than we originally thought. It also sparks our imagination. These tiny humans living on a mysterious island, along side giant killer predators. Not only that, but it shows how our own species has an incredibly diverse history. There is so much still to learn about this enigmatic human. How they got here. Who did it evolve from. We know from Liang Bua that they lived on Flores from at least 200,000 to 46,000 years ago. But did they get here earlier than that? Did they survive longer than that? Were they spread across the entire island? There is a myth on the Island of small people living in the forest, the ebu gogo. Fascinatingly this myth comes from a different region, over 100km away. Future excavations could show that the hobbit lived across Flores and even overlapped with our own species. Today, palaeoanthropology is revealing fascinating insights into our ancient relatives, and our own species. Tomorrow, who knows what discoveries we will see.

Written by Jan Freedman (Twitter @JanFreedman)

A very special thank you to Paige Madison for spending the time to talk to me for this blog post, and sharing her passion for Homo floresiensis. If you don’t already, follow Paige on Twitter (@FossilHistory)

Further reading:

For a nice read about the myth of the ebu gogo on Flores: The myth of the ebu gogo.

There is nice background to the hobbit here: The hobbit at 15.

Read more about those giant rats: Hobbit humans story gets a twist from thousands of rat bones.

Paige wrote about her time she spend in Liang Bua at night: Nightfall in the hobbit cave.

Argue, D., & Groves, P. 2017. The affinities of Homo floresiensis based on phylogenetic analysis of cranial, dental and postcranial characters. Journal of Human Evolution. 107. pp.107-133. [Abstract only]

Argue, D., et al. 2009. Homo floresiensis: A cladistic analysis. Journal of Human Evolution. 5. pp.623-639. [Abstract only]

Brown, P., et al. 2004. A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature. 431 (7012). pp.105-1061. [Abstract only]

Brumm, A., et al. 2010. Hominins on Flores, Indonesia, by one million years ago. Nature. 464 (7289). pp.748-752. [Abstract only]

Culottta, E. 2005. Palaeonantrhopolgy – new hobbits bolster species, but origins still a mystery. Science. 310. pp. 208-209. [Abstract only]

Détroit, F., et al. 2019. A new species of Homo from the Late Pleistocene of the Philippines. Nature. 568. pp.181-186. [Abstract only]

Ingicco, T., et al. 2018. Earliest known hominin activity in the Philippines by 709 thousand years ago. Nature. 557 (7704). pp.233-237. [Full article]

Jungers, W. L., et al. 2009. The foot of Homo floresiensis. Nature. 459 (7243). pp.81-84. [Abstract only]

Mijares, A. S., et al. 2010. New evidence for a 67,000 year old human presence at Callao Cave, Luzon, Philippines. Journal of Human Evolution. 59 (1). pp.123-132. [Abstract only]

Moorwood, M. J., et al. 2004. Archaeology and age of a new hominin from Flores in eastern Indonesia. Nature. 431 (7012). pp.1087-1091. [Abstract only]

Sutikna, T., et al. 2016. Revised stratigraphy and chronology for Homo floresiensis at Liang Bua. Nature. 532 (7599). pp.366-369. [Abstract only]

Weston, E. M., & Lister, A. M. 2009. Insular dwarfism in hippos and a model for brain size reduction in Homo floresiensis. Nature. 459 (7243). pp.85-88. [Abstract only]

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In cold pursuit

From feathered dinosaurs to woolly mammoths, countless animals that no longer live have come to pervade modern popular culture. Snuck into a world of dragons, witches, and ice zombies in Game of Thrones (or A Song of Ice & Fire), the dire wolf recently experienced a slightly confusing reintroduction into the beloved pantheon of extinct megafauna, as it may appear to some to be mythical by association. Dire wolves were very much real, and we have known about them since the mid-nineteenth century. These charismatic canids roamed the Americas and parts of eastern Asia for more than 100,000 years, going extinct early into the Holocene around 9,000 to 10,000 years ago (BP).What were they really like, and why did they go extinct? In answering these questions, we can also begin to explore the diverse ways in which information is gleaned from fossils.

We start our story in the La Brea Tar Pits in Los Angeles, USA, the largest discovered fossil site containing dire wolves, numbering beyond 4,000 individuals. Tar pits form from crude oil seeping up to the earth surface and congealing into asphalt. The La Brea Tar Pits contained the remains of thousands of animals representing several extant and extinct species that fell into and became deposited in the asphalt between 40,000 and 8,000 BP.  Excavations at La Brea began in 1913, and the asphalt-preserved fossils continue to be used to reimagine not just the organisms themselves, but also the world that they inhabited.  

The wall of dire wolf skulls on display at La Brea. This display holds around 400 skulls. (Photo Jan Freedman)

A predator and its prey

One way to get to know an apex predator is through its preferred prey. Many chemical elements exist as multiple, stable isotopes that carry different numbers of protons in their nuclei. For instance, carbon exists as the common type 12C and the much rarer 13C, while nitrogen exists as the common and rare 14N and 15N, respectively. The stable isotope ratios 13C/12C and 15N/14N vary across different kinds of plants based on their environment and how they incorporate the elements from the atmosphere, and in animals depending largely on their diets. Stable isotope compositions of biological tissues such as bone can reconstruct ancient diets and food webs. A 2007 study first identified how isotope ratios in modern wolves are related to that in their prey, beavers and moose. Applying these findings to isotope ratios in the bones of dire wolves and several candidate herbivore prey species from the La Brea Tar Pits, the authors inferred that dire wolves primarily preyed on horses, and to a lesser extent on mastodon, sloth, and grazers such as bison.

A model of a dire wolf on display at La Brea. (Photo Jan Freedman)

We know dire wolves were likely pursuit predators who chased down their prey and attacked with their jaws alone, based on our knowledge of extant wolves and other canids. This has also been verified through fossil evidence. The authors of a 2017 study predicted and found that patterns of skeletal injuries differed between La Brea dire wolves and sabretooth cats, which were likely ambush predators. Sabretooth cats had frequent spinal injuries from grappling with their prey, while dire wolves tended to have high rates of trauma across all four limbs, consistent with chasing down prey.

Clues to extinction

Patterns and frequencies of tooth wear and damage have been found in living animals to be informative of feeding behaviors. A 1993 study brought this understanding to the study of several La Brea carnivores, including dire wolves. The authors found a high frequency of tooth breakage across the carnivores, likely from tooth-bone contact, suggesting greater utilization of carcasses compared to modern carnivores. Was this due to a decline in available herbivore prey in the late Pleistocene, eventually leading to the extinction of these predator species?

To answer this question, a 2002 study compared dire wolves preserved in two La Brea pits dated to ~15,000-14,000 BP and ~13,000-12,000 BP, respectively, and found that carcass utilization actually decreased over this time span. Times appear to have been especially tough around ~15,000-14,000 BP, leading to more complete consumption of prey to avoid scavenging by other competing predators. The subsequent decline in this behavior may reflect dwindling predator densities as dire wolves and other carnivores approached extinction. A 2015 study found a similar temporal pattern, among other findings.

The study investigated several measures of morphological variation using the remains of 83 dire wolves as well as 97 sabertoothed cats from La Brea, spanning the period between 40,000 and 12,000 BP. One of these measures, fluctuating asymmetry, quantifies (to a reasonable extent) developmental instability, the tendency of traits to deviate from the target phenotype. Symmetrical traits such as the left and right sides of the face are controlled by the same genetic and developmental pathways, and any asymmetry implies developmental instability, typically caused by some form of external stress. The study found increasing fluctuating asymmetry in dire wolves over time from 40,000 BP until ~15,000-14,000 BP, possibly in response to environmental stress associated with rapid climatic transitions during that period. This was followed by a decline in fluctuating asymmetry 13,000-12,000 years ago, mirroring the changes in tooth wear and breakage over the same interval. Together, these studies imply that climatic instability leading up to the Holocene put dire wolf populations under stress, likely through disrupting populations of their herbivore prey, which they never completely recovered from. Humans are also thought, quite contentiously, to have played some role in Pleistocene megafaunal extinctions.

A dire wolf skeleton, mounted in pursuit of prey. (Photo Jan Freedman)

A wolf by any other name

We end with a reflection on the evolutionary relationships of the dire wolf. Over the last two decades, enormous advances have been made in techniques to extract preserved DNA from ancient remains. Ancient DNA provides snapshots of the evolutionary past, and in the case of extinct animals, a way to infer their relationships with extant taxa. A 2021 study looked at ancient DNA from dire wolf remains, and found that dire wolves were in fact distantly related to extant gray wolves. The two species had diverged from a common ancestor more than 5 million years ago, and look so similar largely because they convergently adapted to lives of pursuit predation. To place this in context, jackals, coyotes, and gray wolves are more closely related to each other than to dire wolves.

While modern canids like grey wolves and coyotes are known to sometimes interbreed, the study found that this was not the case between dire wolves and grey wolves. Hybridization leads to the introduction of new genetic diversity, which can often help a species adapt to changing conditions. Dire wolves were not beneficiaries of this process as they disappeared along with the prey species they had been adapted to hunting and eating.

Humans have likely been coming across and pondering fossilized remains of extinct animals for thousands of years. Records of such encounters are thought to persist today in the form of mythological beasts reimagined from the fossils, such as giants, griffins, and dragons. Modern day reconstructions from fossil remains are, as we have just seen, much less fanciful, but far more exciting in what they tell us about ecosystems and episodes in evolutionary history that have been lost to time.

Written by Ornob Alam (Twitter @genomeinquirer)

Edited by Jan Freedman (Twitter @JanFreedman)

Ornob is a graduate student in Michael Purugganan’s lab at New York University. His dissertation research examines the demographic and evolutionary history of domesticated Asian rice in the context of past climate change and human migrations.

Further reading:

Binder, W. J., Thompson, E. N., and Valkenburgh, B.V. 2002. “Temporal variation in tooth fracture among

Rancho La Brea dire wolves,” Journal of Vertebrate Paleontology, vol. 22, no. 2, pp. 423–428, Jul. 2002, doi: 10.1671/0272-4634(2002)022[0423:TVITFA]2.0.CO;2. [Abstract only]

Broughton, J. M., and Weitzel, E. M, 2018. “Population reconstructions for humans and megafauna

Suggest mixed causes for North American Pleistocene extinctions,” Nature Communications, vol. 9, no.

1, Art. no. 1, Dec. 2018, doi: 10.1038/s41467-018-07897-1. [Abstract only]

Brown, C., Balisi, M., Shaw, C. A., and Van Valkenburgh, B. 2017. “Skeletal trauma reflects hunting

behaviour in extinct sabre-tooth cats and dire wolves,” Nature Ecology & Evolution, vol. 1, no. 5, Art. no.

5, Apr. 2017, doi: 10.1038/s41559-017-0131. [Abstract only]

Fox-Dobbs,K. F. D.,  Bump, J. K. B. K., Peterson, R. O. P. D., Fox D. L. F., and P. L. K. L. Koch, P. L. K. 2007.

“Carnivore-specific stable isotope variables and variation in the foraging ecology of modern and ancient

wolf populations: case studies from Isle Royale, Minnesota, and La Brea,” Canadian Journal of Zoology,

doi: 10.1139/Z07-018. [Abstract only]

Goswami A., Binder. W. J., Meachen, J., and O’Keefe, F. R. 2015. “The fossil record of phenotypic

Integration and modularity: A deep-time perspective on developmental and evolutionary dynamics,”

Proc Natl Acad Sci U S A, vol. 112, no. 16, pp. 4891–4896, Apr. 2015, doi: 10.1073/pnas.1403667112.

[Full article]

Perri, A. R., et al., 2021. “Dire wolves were the last of an ancient New World canid lineage,” Nature, vol.

591,No. 7848, Art. no. 7848, Mar. 2021, doi: 10.1038/s41586-020-03082-x. [Abstract only]

Stewart, M., Carleton, W. C., and Groucutt, H. S. 2021. “Climate change, not human population growth,

correlates with Late Quaternary megafauna declines in North America,” Nature Communications, vol.

12, no. 1, Art. no. 1, Feb. 2021, doi: 10.1038/s41467-021-21201-8. [Abstract only]

Vanvalkenburgh, B., and Hertel, F. “Tough times at la brea: tooth breakage in large carnivores of the late

pleistocene,” Science, vol. 261, no. 5120, pp. 456–459, Jul. 1993, doi: 10.1126/science.261.5120.456.

[Abstract only]

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