Island hopping hippos

My mum passed away suddenly at the beginning of January. It was a huge shock. It still is a huge shock. It still doesn’t seem real that I will never see her again. Life is so fragile. I wish there could have been more time. She was an exceptionally kind woman, and had a wicked sense of humour (traits which I hope have been passed on to me). Whenever I visited my folks, her and I would escape my chaotic loud siblings and play Scrabble for over an hour (she always won). We would catch up, and she would always chuckle endearingly at my nerdy fossil talk.

I wanted to write a little post that would have made her smile. There are thousands of animals that are good mothers: birds, mammals, even reptiles. But I think she would have liked something a little unusual. A little different. A post about weird hippos would have done the trick.

Despite the African hippopotamus (Hippopotamus amphibius) being a massive herbivore, there is something about them that is pretty special. They are undoubtedly adorable creatures: their huge curved mouths that look like a big smile; those short stumpy legs waddling; those big soft eyes. And they are extremely good mothers. The Ancient Egyptians knew this, and worshiped the half-hippo, half-human goddess Taweret who protected pregnant women during childbirth. The mighty hippopotamus even makes a slightly comical appearance in music, with Edward Keffer’s ‘Hippopotamus Polka’, and a delightfully flamboyant accompanying illustration.

My mum would have seen the humour in this. A somewhat flamboyant, yet gallant, hippopotamus taking the lead. The image is from the ‘Hippopotamus polka’. (Image public domain)

Then there’s also the lovable, but highly threatened, pygmy hippos (Choeropsis liberiensis). These little beasts are only around 0.8 meters: an adult would reach up to my hips! Coming out at night in forests to feed on ferns, grasses and fruit, they live in just three areas in Africa. Pygmy hippos are a different genus to the larger species, which means they didn’t evolve from the larger Hippopotamus amphibius, but shared a common ancestor some 8 million years ago.

A very cute pygmy hippo (Image public domain)

Today hippos are restricted to the continent of Africa. In the past they were widespread across Europe, with a number of different species. Our familiar large African beast was even shuffling around in Britain. Not all hippos outside of Africa were big. Some were pretty small. And I’m not talking about pygmy hippos.

Islands are fantastic harbingers for evolution to run wild. Originally desolate places, any species that makes their home there has unique opportunities to explore new niches. Seeds and insects are blown to islands by the winds. Some animals accidentally end up there by sitting on logs. Some even swim there. Once there they have little competition compared to their home lands, and evolve some incredible adaptations for their new environments.

Not all island inhabitants are the new comers. Some arrive long after flora and fauna have been established on this isolated paradise. And some strange things can happen. Small animals can evolve relatively quickly to be pretty darn big, like the Maltese dormouse, or the komodo dragon. With little competition and less predators than the continent, these small animals exploit the new environment and enjoy the new bounties.

Small animals become big. The very opposite happens to big animals: over time they shrink! There are three species of mammoths that shrunk to pure cuteness in the past, and it has happened to our own genus too, with the enigmatic Homo floresiensis on the Indonesian island of Flores. Large animals need a lot of food to survive. Those individuals who are a little smaller and can survive with less food have more offspring. A lack of predators also means they don’t need large size for safety. And so, through time, the species becomes smaller.

The Mediterranean Sea, with it’s half a dozen large islands. (Image from Google Maps)

The warm Mediterranean Sea is scattered with dozens of islands. Today they are popular tourist getaways to enjoy the sun and the sea. Not too long ago they would have been very different with some truly incredible animals. Two of these islands were home to dwarf mammoths: the Sardinian dwarf mammoth and the Cretan dwarf mammoth. Perhaps more incredibly, four islands had hippos living on them!

As well as a dwarf mammoth, Crete had a dwarf hippo (Hippopotamus creutzurgi). Sicily, Malta and Cyprus also had dwarf hippos (H. pentlandi; H. melitensis; and H. minor respectively). Around the same size as the pygmy hippo, these little hippos were not their close relatves. Skeletal features suggest that they evolved from the hippo that was at home in Europe, H. antiquus, most likely four separate times.

The smallest of the Mediterranean dwarf hippos, Hippopotamus creutzburgi. (Image by Twilight Beasts)

Lower sea levels in the Mediterranean between 150,000 and 100,000 years ago meant that animals did not have as far to swim to these islands (relative to today!). And hippos can swim quite well. Once big lumbering hippos first stepped ashore, there were no natural predators. These hot islands may seem like an unusual habitat for hippos, but the environment was different then. Examining oxygen isotopes in nearby Macedonia, shows it was cooler and wetter from around 100,000 years ago compared to today’s climate. These plump little beasts would have waddled around in pretty lush forests feeding on grasses, shrubs and fruits.

What a sight they must have been.

We don’t know for sure exactly when or why these buxom (a word my mum would have liked) beasts disappeared. Today the Mediterranean islands are hot and very dry. British people travel there in their thousands every year only to return with ghastly red and sunburned skin. The Mediterranean began to warm up quite quickly around 25,000 years ago. With a warmer climate comes a drier, harder environments for animals, especially those which love the wetness. More research needs to be done on these well-rounded little animals until we can say much more.

There’s more cute hippos to add to our list, the Madagascan dwarf hippos (Hippopotamus (sometimes called Choeropsis) madagascariensis; H. lemerlei; H. laloumerna), which lived in, well, yes, Madagascar! There may well have been three species living on the large island of Madagascar.  They were very small, smaller perhaps than the pygmy hippo. Living in freshwater highland environments, their very well worn teeth indicate slightly tougher vegetation than their bigger ancestors, Hippopotamus amphibious.

Just look at the size of this hippo! The dwarf Madagacan hippo Hippopotamus (Choeropsismadagascariensis. (Image by Osborn, public domain)

What’s truly fascinating is that these hippos lived until very recently, just around 1000 years ago. There’s even evidence of cut marks on bones, showing that humans were not too shy to eat them. For these species, the arrivals of humans to Madagascar around 2000 years ago was their end. Small, chubby legs were no way set up for outrunning fast predators. Sadly they vanished around the same time William the Conquer became King of England.      

When species have gone, they are not gone really. Our blog posts keeps these wonderful creatures alive. I like to think the same is true when someone has passed away. I know that they will never really be gone.  It is our memories of our loved ones that keep them alive inside us. Just like we share our blog posts, our memories too can be shared, so they are still alive in our children, and their children too. I don’t know if my mum ever read any of my blog posts, but I’m pretty sure if she read this and discovered tiny, cute, plodding dwarf hippos were once alive, she would have smiled to herself.

Written by Jan Freedman (@JanFreedman)

Further reading:

Adams, A. L. (1863),  ‘Observations on the Fossiliferous caves of Malta’. Journal of the Royal Society, 4 .2. pp.11–19.

Burney, D. A. ,et al. (2004). ‘A chronology for late prehistoric Madagascar.’ Journal of Human Evolution: 25-63. [Full article]

Carroll, F. A., Hunt, C. O., Schembri, P. J., & Bonanno, A. (2012). ‘Holocene climate change, vegetation history and human impact in the Central Mediterranean: evidence from the Maltese Islands’. Quaternary Science Reviews. 52. pp.24-40. [Abstract only]

Dewar, R. E. (1984). ‘Extinctions in Madagascar. The loss of the subfossil fauna.’ In: P. S. Martin and R. G. Klein (eds), Quaternary extinctions. A prehistoric revolution, pp. 574-593. The University of Arizona Press, Tucson, AZ, USA. [Book]

Dobson, M. (1998). ‘Mammal distributions in the western Mediterranean: the role of human intervention’. Mammal Review.28.2. pp.77-88. [Abstract only]

Hunt, C. O. (1995). ‘The natural landscape and its evolution’. In: Barker, G. (Ed.), A Mediterranean Valley.  Leicester:Leicester University Press. pp.62-83.[Book]

Lacey, J. H., et al. (2016). ‘Northern Mediterranean climate since the Middle Pleistocene a 637ka stable isotope record from Lake Ohrid.’ Biogeosciences. 13. pp.1801-1820. [Full article]

MacPhee, R. D. E. & Burney, D. A. (1991). ‘Dating of modified femora of extinct dwarf hippopotamus from southern Madagascar: implications for constraining human colonization and vertebrate extinction events’. Journal of Archaeological Science 18: pp.695-706. [Full article]

MacPhee, R.D.E. & Flemming, C. (1999).’ Requiem Aeternam. The last five hundred years of mammalian extinctions.’ In: R.D.E. MacPhee (ed.), Extinctions in Near Time, pp. 333-371. Kluwer Academic/Plenum Publishers, New York, USA. [Book]

Stuenes, S. (1989). ‘Taxonomy, Habits and relationships of the subfossil Madagascan Hippopotami Hippopotamus lemerlei and H. madagascariensis.’ Journal of vertebrate Paleontology. 9(3). op.241-268. [Abstract only]

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The most (and least) read posts of 2017!

It’s that time of year again when websites shout about their most read blog posts. Of course it’s a little bit of self promotion, but it is also quite interesting to see what has been popular over the last year.

In our little annual tradition we will share with you the top five posts along with the least read five posts of the year. We think it’s quite nice to share the ‘bottom’ five posts to spread a little love to these undiscovered gems. (We should obviously say that these are not the least read because they are not interesting – all our posts are interesting! It might be that they are not as sexy as the big beasts, or that they have not been shared enough. Whatever the reason, these five least read posts are a fantastic little read.)

We really are so very grateful for your continued support by reading this blog and we have loved engaging with so many of you on the blog and on Twitter this last year. We hit 250,000 views on our blog just a few months ago – which is incredible! Thank you readers for your encouragement and support for this blog site.

Least read blog posts of 2017:

  1. When life gives you lemmings… Discover how a classic 1980s video game links to small arctic mammals in Britain. Give these little fury critters a boost!

The Norwegian Lemming (Lemmus lemmus) is just one species of lemming. (Image by Oma Kuva. Public Domain)

2. Big find in little China. An amazing fossil discover in 2017 could put humans in China around 120,000 years ago.

3. Mini-beasts, giants and mega-floods. From beetles to mammoths, fossil evidence can help us to understand when the English Channel formed.

4. Time capsules from the Ice Age: Find out how nature’s collectors have helped to preserve evidence from past environments.

5. Forever young: Like Peter Pan, the Key Deer in Florida almost never grow up. Find out how this beautiful little deer stays youthful throughout their lives.

Most read blog posts of 2017:

  1. A very brief introduction to mammoths: This is a mammoth post. Literally. There were ten species of mammoths from giants to dwarves.

The smallest mammoth that has ever lived, the mighty-mini Cretan Dwarf Mammoth

2. The stuff of night-mares: A clever title. A great post. About a freakin’ enormous horse!

3. Mammoths! Mammoths make it twice in the top five. This post is about our familiar giant, the Woolly Mammoth.

4. The lonely walk to extinction: We are pleased this post has been read quite a lot. It brings home just how vulnerable species are, and how those last few individuals have a very hard, lonely life.

5. Lost as the Moa is lost! This is the second year running this fantastic post has made it into the tope 5. Read it and you will see why!

We wish all our readers are very happy and healthy 2018. And we are looking forward to some exciting things in 2018, and of course, lots of new Beasts to share with you! Ross (@DeepFriedDNA), Rena (@JustRena) and Jan (@JanFreedman)

Follow us on Twitter – @Twilightbeasts 

Posted in Arctic Ground Squirrel, Homo sapiens, Horse, Key Deer, Lemming, moa, Woolly Mammoth, Woolly Rhinoceros | Tagged , , , , , , , , , , , , , , , , , , | 3 Comments

“Nice Beaver!” (redux)

Beavers! Majestic dam makers of Canada. Living on a diet of maple syrup and poutine. Probably. I don’t know.

Much bigger in the past, North America had Castoroides ohioensis, the giant beaver. As big as a bear. With its razor sharp incisors it could have felled trees and predators alike.

Here in Blighty we have a few beavers (Castor fiber) here and there. These prodigal sons have popped up in the Highlands, Argyll, Devon, Tayside. Some are legal beavers, and some are illegal beavers. The beaver population in Argyll, at Knapdale forest, are the product of the first licensed reintroduction of a mammal to Britain. Closely monitored by Scottish Natural Heritage, the Knapdale beavers are recolonisers who have been helped by the Scottish government to return to lands they were only recently removed from. Some of the other beaver populations are of unknown origins, occupying a legal grey area and not offered the same protection. Some of these new beavers have been shot by landowners, who if not actively disgruntled are pretty far from gruntled.

Castor fiber, survived very late in Britain. It only really disappeared in the 16th century, when incessant demand for furs and anal secretions* led to its extirpation.

Anyway, if we go back to the Middle Pleistocene (and why not), there was a big British beaver to be found. Sympatric with Castor fiber, Trogontherium cuvieri had a pretty large distribution from England to China in a fairly narrowly confined band. Its fossils are known from France, the Netherlands, Germany, Russia, although it probably only evolved in the Late Pliocene. It must have had fairly specific climatic tolerances because there are no known fossils from south of the Alps or the Pyrenees. We know it was also a river-dweller as that is where the vast majority of the fossils of this species have been found. While not quite as big as ol’ Castoroides, this was still a sizeable animal. Analysis of skulls show that metrically Trogontherium was nearly 50% bigger than Castor. To put that into some context, the incisors in Trog could be up to seven inches long: that’s as big as the canines of Smilodon fatalis!

Skull of Trogontherium cuvieri by E. T. Newton. Public Domain Image

There has been a lot of discussion about what Trogontherium was doing with its enormous incisors. General consensus today is that it didn’t use them for cutting down trees, like its modern day cousin. The incisors have a different profile; they are more convex and would have acted more like a gauge than a chisel. We actually have fossil trees from East Anglia, from the Middle Pleistocene when both beaver species were around, and they show tooth marks that match Castor rather than Trogontherium. Fossil trees can in fact be a marvellous repository of information about animals of the past: I remember seeing an early Holocene log on display in the National Museum of Scotland, that clearly shows the gnaw marks of a beaver from long ago. It seems likely that Trog used their oversized teeth for digging at roots or in burrowing into the ground.

from Fostowicz-Frelik (2008)

One other weird point of discussion has been what the lips of Trogontherium looked like. Based on bony tubercles preserved on the maxilla above the upper incisors, some scientists reconstructed it with hyper-mobile Jagger lips that could act like tiny fingers to slurp up food. It has often been compared to the coypu (Myocastor coypus) which also has prehensile lips. Coypu are also known colloquially as nutria, and they are native to South America. Thanks to humans they have been spread worldwide, to North America, Africa, and Europe. Bred for their fur, escapes and releases have let them into places where they had no right to be. They used to be a common sight in East Anglia, where many Trogontherium fossils have been found. They terrorised Norfolk from about 1929 until an eradication campaign in the 1960s and 1970s. This along with a series of severe winters helped to wipe them out by the late 1980s. I like to think that this bit of accidental rewilding may have given East Anglia something it hadn’t had since the Middle Pleistocene- a Trogontherium analogue!

 

*yeah. Beaver anal secretions, called castoreum, have long been used as a medicine and perfume. Even back in Roman times. It is still used in the modern era to give perfumes a “leather” note, so you’ve probably smelt it and not realised. But that’s nothing. You’ve also probably eaten it. Castoreum is still used sometimes today as an additive to give food a vanilla flavour. Enjoy your next ice cream!

Written by Ross Barnett (@DeepFriedDNA)

A link to one of the best sight gags ever, from the Naked Gun (source of this article’s title)

Further Reading:

Fostowicz-Frelik, L. “First Record of Trogontherium Cuvieri (Mammalia, Rodentia) from the Middle Pleistocene of Poland and Review of the Species.” [In English]. Geodiversitas 30, no. 4 (2008): 765-78. [Full Text]

Kurtén, B. Pleistocene Mammals of Europe. London: Weidenfeld and Nicolson, 1968. [Book]

Mayhew, D. F. “Reinterpretation of Extinct Beaver Trogontherium (Mammalia, Rodentia).” [In English]. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 281, no. 983 (1978): 407-38. [Full Text]

Newton, E. T. “Trogontherium from the Pleistocene of Copford, Essex.” [In English]. Geological Magazine London Dec 6 3 (1916): (322-23). [Full Text]

Owen, R. A History of British Fossil Mammals and Birds. London: John Van Voorst, 1846. [Book]

 

 

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Tamed: ten species that changed our world

The strong autumn sun shines powerfully on the hills in front of me. Yellows, oranges, reds, and browns light up in a dazzling array of hues, as if the trees themselves are on fire. Three horses munch grass in a field below, oblivious to the beautiful display around them. Silence surrounds everything.

Suddenly, my neighbour’s dog barks, snapping me back to life. I turn around and see my very cheeky looking children, with big smiles on their faces, covered in flour. Hands. Jumpers. Face. There seems to be more flour out of the mixing bowl than in it. Fortunately they have done a good job at mixing together the flour and butter to make the pastry. And there is still enough. Soon the sweet, mouth-watering smell of apple pie will float through the rooms in our house.

Horses. Flour. Dogs. Apples. It’s truly astonishing how many species we use in our every day lives. We take it for granted, but these everyday species were, and still are, key to our very survival. When did we domesticate these key species? How did we? What made us chose them, or did they choose us?

These questions and much more are discussed in Professor Alice Roberts latest book, Tamed: Ten species that changed our world.

A rather excited blogger with his copy of Tamed to review. (Photo by author using a camera balanced on a shelf. 10 second timer. Best photo out of 8 taken.)

This book is an utter delight. Focusing on ten different animals and plants, including ourselves, Roberts traces back the origins for the first evidence we have for domesticating these species. From rice to wheat and horses to cows, we find out how important they were to our survival at key events in human history. It’s not an easy story to tell, but the text is clearly written, and there is a charming poetry to her writing throughout.

The domestication of species, or taming of nature, is simple for us to think about today. We see farms full of sheep, chickens and cows. They are tamed. Millennia ago, it was a different story. The first tamed species was likely a horrendous process of trial and error: hope and disappointment. Roberts tracks the very first evidence for taming these animals in the archaeological record: tiny smears of horse milk on thousand year old broken pottery, signs of a single seed. The archaeology is fascinating and sometimes frustrating because there are natural gaps in what has been preserved, or even sites we have visited.

Horses, for example, should be extinct. They are one of the few remaining mega-fauna still with us today. They were food for humans and most archaeological sites have butchered horse bones. Unlike the woolly mammoths in Europe, or the giant sloths in the Americas, they survived. And there are millions of horses on Earth today. Sometime around 5000 years ago is evidence of horses being tamed close to the Caspian Sea. Bones and residual enzymes from horse milk hint at taming the beast. Milk, food, helping with farming, or just the simple reason that someone jumped onto the back of a horse and rode them, changed the fate of this big beast.

Ice age horses played a key part in the survival of humans in Europe. (Art © Tabitha Patterson)

Clues in the ground give tantalising hints about the first sites of taming the wild. Roberts goes even further, and explores the very building stones of species. Each chapter examines the latest genetic evidence to help answer the riddle of the first tamed animal or plant. I like how it sometimes agrees with the archaeological evidence, and sometimes throws up surprises. Actually the genes that make up our tamed species today show that the road to being tamed was not simple, and in some cases may have been accidental. There are over 7,500 different varieties of apples today. Getting to the core of taming the forbidden fruit needed genetics. And it turns out that although apples have been growing in China for over 2 million years, the ‘tamed’ apples have a huge genetic diversity and show that they are a mix of those Chinese fruits and crab apples. As they spread west they pollinated with wild crab apples. Hybrids like this are seen with wheat, rice and potatoes making the ‘original’ source more complicated than simple.

There are other fantastic quirks to the book too. We find out how the tamed species spread across the globe. The first potatoes from the Americas, to the first apples to the Americas, there are wonderful stories about how these different species are so important in more recent history and the effect they had. Although the famous forbidden fruit in the story of the Garden of Eden is said to be an apple, Roberts shows why actually this isn’t the case. These little links to more recent history, ones were are familiar with, gives each chapter a delightful knowledge burst.

What is a wonderful treat is how each chapter delves into the evidence from the archaeology and the genetics, yet it is cautious to say exactly when and how that very first animal or plant was tamed. It’s a treat because we are normally told that this this or that happened. The taming of nature is not so clear. We can imagine someone 10,000 years ago planting a seed, but as much as the genetics and the evidence in the ground can tell us, we can never know why that person did. We know they did because we see it all around us every day. That legacy of a single person or small group of people lives on today, and was, and still is, vital to the survival of our species.

I have only one qualm with the book – it isn’t really a qualm, more of me being a little spoilt and wanting a little more. As well as a wonderful science writer and scientist, Roberts is also a gorgeous artist. Each chapter begins with the usual title, as would any book. Tamed is different. Above the chapter title are beautiful illustrations of the species about to be discussed. Three blades of wheat. An aurochs skull. Hand drawn in ink, they speak so many words. It would have been wonderful to have seen some more illustrations supporting the text. I can imagine Roberts’ drawings of where the Fertile Crescent is, or some different dog breeds, and they are gorgeous. For some parts of the book illustrations would help the reader visualise the places, or even the genetics, nicely.

I loved this book. I loved the stories, the information. But what I loved most was the message of the book: how to preserve what we have before we lose it forever. Humans have a massive impact on the plant, both locally and globally. With an enormous population of over 8 billion people, we need food to survive. That food is the tamed species we reply on. And they need space to live so we can use them. But at what cost? Clearing rainforests so our tamed species can be farmed is killing life, whole ecosystems. We need to find a balance before too much is lost. Roberts says it much better than I can:

“We’re clever – that’s always been a characteristic of humans. But we need to be cleverer than ever if we’re going to find a way of balancing the voracious appetite of a growing human population, and the hordes of tamed species we need to survive, with biodiversity and wilderness.”

Written by Jan Freedman (@JanFreedman)

Further reading:

Roberts, A. (2017) Tamed: Ten species that changed our world. Penguin Random House

Posted in Aurochs, Dog, Horse | Tagged , , , , , , , , | 5 Comments

Walking on thin ice

No other animal symbolises climate change like the polar bear does. Just like the dodo has become the standard animal representing extinction, the polar bear has become recognised as the animal signifying our impact on the planet’s rapidly warming climate.

TV programmes, newspapers and magazines all use an image of a polar bear when talking about climate change. There is the classic image of a lone polar bear standing on all fours on a small piece of ice, in the vastness of empty water. The fur is wet, and clearly this large creature is being portrayed as being very cold. Its thick padded, webbed feet, grip onto the freezing ice. The great white bear is looking out longingly to sea, searching for that next piece of ice it can swim to, hoping that there is a tasty seal just lying there waiting.

It is an extremely powerful image. A great creature, losing its home because of our selfishness. It is a stark reminder of the enormous effect we can have on our home; the home of millions of different species, each unique, and each just as beautiful as the next.

A starving polar bear on extremely thin ice, at Svalbard. (Photo by Andreas Weith. Public Domain)

Polar bears belong to a rather remarkable genus in the bear family, Ursus. Species from this group have conquered the northern hemisphere: the brown bear (Ursus arctos) living in North America and Eurasia; the widely distributed American black bear (Ursus americanus); the tree loving Asian black bear (Ursus thibetanus); and the one that made its home with the sea and ice, the polar bear (Ursus maritimus). For just one genus, this is hugely successful: species are found all over North America, and Asia, and even the northern cold ice sheets. In the past there have been over a dozen different types of bear placed in this genus, including the giant Cave Bear.

Out of the four living species, the polar bear is the largest. And perhaps the most bizarre.

The beautiful polar bear (Ursus maritimus) in Alaska. (Photo by Alan Wilson. Public Domain)

Polar bears are bears. Bears that hibernate, like other bears. But polar bears dig a den deep underneath the snow, and hibernate inside a snow-den! Their thick hair and layers of fat allow this giant to survive the freezing temperatures. Unlike other bears, the polar bear can swim for a very long time: up to a week non-stop. Their huge padded feet help spread the weight when walking on the ice, and it also helps in swimming. This bear also hunts seals: yes, the polar bear decides to spent a lot of time hunting an animal that is superbly adapted to life in the water. (Polar bears do not solely rely on seals for food. They will eat other animals, including washed up whale carcasses, as recently seen on Wrangel Island.)

Surprisingly, these are a very recent species to appear. Evolving from a population of brown bears, the oldest polar bear fossil so far found is only around 110,000 years old on the Norwegian archipelago, Svalbard. With much of the Arctic Ocean frozen over during the Late Pleistocene, some brown bears slowly took advantage of this dramatic change in environment. The heritage with brown bears is important, because the two species still can produce hybrids. Locked within the genomes of polar bears is a genetic marker that shows all living polar bears alive today are descended from a brown bear –  likely due to polar bear and brown bear mating in the recent past. Researchers had assumed this had been fairly recently, somewhere in Alaska where the two species can overlap. Recent work by geneticist Beth Shapiro and colleagues looked at DNA from brown bears in Ireland. They showed that all polar bears alive today are descended from one Irish female brown bear (and a male polar bear).

The oldest polar bear fossil so far found, dated between 130,000 and 110,000 years old. (Image from Ingolfsson and Wiig, 2008)

Polar bears in Britain and Ireland? It sounds crazy today, but during the Late Pleistocene the world was a drastically different place. The last major glaciation was between 110,000 to 11,700 years ago. (Remember, the ‘ice age’ was not just one long cold stage, but a plethora of cold times, known as glacials, and warm times known as intergalcials.) During this cold time, ice covered much of the Northern Hemisphere, which provided the conditions for brown bears to take advantage of, and we see the first polar bears around this time. With so much ice around, the sea levels were much lower, so animals could move much more freely. Britain itself was at some points covered by glaciers up to two miles thick, as far south as the Thames. This would have been the perfect environment for polar bears. And it seems that around 50,000 years ago one male polar bear met a female polar bear, and their descendants are what we see today.

Monster mysteries are popular all around the world. The legends of Bigfoot, sasquatch, and the Yeti, may all be answered by bear DNA. Samples of hair which have been claimed to belong to these cryptozoological beasts, were taken from across Northern America and the Himalayas and their DNA was analysed. The results showed the hair was actually from a huge variety of real animals, including horses, dogs, cows, and an odd result which we shouldn’t try to think about too much, a human. Some of the results showed that the ‘Bigfoot’ or ‘Yeti’ actually came from Himalayan brown bears. Sadly, the myths of a giant, hairy, bipedal creature is just that: a myth.

This symbolic species owes it’s existence to the incredibly dramatic climate of the last major glaciations. The last 100,000 years or so has not been easy sailing for these animals. The temperature has fluctuated, with the ice sheets waxing and waning which has had an effect on polar bear populations. Today is a different story. Different because of a factor no animals can prepare for: humans. We are having an effect on the whole planet in a way no other species has since maybe stromatolites changed the atmosphere to be more oxygen rich some 2 billion years ago.

There is a reason why polar bears are the symbol for climate change. They have had to cope with temperature changes in the past as their environment shrunk. The difference today is that it is happening fast, faster than natural. Because of our actions, species are unable to respond fast enough to the changes at not just a local level, but at a global level. The polar bear is the poster species for climate change, but there are millions others that are in danger of being lost forever. Climate change is real. It is happening. We al have a responsibility to do what we can.

Written by Jan Freedman (@JanFreedman)

Further reading:

Derocher, A. E., Lunn, N. J., & Stirling, I. (2004). ‘Polar bears in a warming climate.’ Integrative and Comparative Biology. 44(2). pp.163-176. [Full article]

Edwards, C. J. et al. (2011) ‘Ancient hydridization and an Irish Origin for the Modern Polar Bear Matriline.’ Current Biology. 21. (15). pp.1251-8. [Abstract only]

Hailer, F., et al. (2012). ‘Nuclear Genomic sequences reveal that polar bears are an old and distinct bear lineage.’ Science. 336(6079). p.344-7. [Abstract only]

Ingolfsson, Ó., & Wiig, Ø. (2008). ‘Late Pleistocene fossil find in Svalbard: the oldest remains of a polar bear (Ursus maritimus Phipps, 1744) ever discovered.’ Polar Research. 28: pp.455-462. [Full article]

Kurten, B. (1964). ‘The evolution of the polar bear, Ursus maritimus Phipps.’ Acta Zoologica Fennica. 108. pp1-30.

Lindqvist, C., et al. (2010). ‘Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear.’ Proceedings of the National Academy of Sciences, USA. 107 (11): pp.5053-5057. [Abstract only]

Liu, S., et al. (2014) ‘Populations genomics reveal recent speciation and rapid evolutionary adaptation in polar bears.’ Cell. 157(4). pp.785-794. [Abstract only]

Posted in Brown Bear, Polar Bear | Tagged , , , , , , , , , , , , | 17 Comments

The lonely walk to extinction

Our very species is an oxymoron. When Linnaeus added us to the taxonomic ranks of life, he dubbed humans Homo sapiens: literally meaning ‘wise man’. Sometimes I wonder how ‘wise’ we are. We can send people to live in space, talk to another person instantly across the world; yet we can chop down a rain forest, hunt rare animals for fun, and have seemingly little awareness of our disastrous impact on the planet. So many species have disappeared in the last 10,000 years that our planet is only a fraction of the beautiful diversity that once was. And despite cloning and sexy ‘resurrection’ stories, once a species has become extinct, that’s it, it’s gone.

What is perhaps most frustrating is that through social media we can instantly see another dozen acres of rainforest lost to logging, or we count down the last surviving individuals of a species. Frustrating because we know it is happening yet there is little we can do. And sad because we are witnessing animals disappear right before our eyes with literally the last few numbers counting down to zero.

Even before a species number reaches zero, there is a point where that animal is functionally extinct. Less than a dozen animals left and it is unlikely for that group to grow in numbers and recover. Despite a few individuals still alive in zoos today, the Western black rhino (Diceros biceros lonipes) was declared extinct in 2013. The Javan rhinoceros (Rhinoceros sondaicus) has less than 70 individuals left in the wild: this species is already on its way to extinction.

The Javan rhinoceros has been hunted for centuries. This painting by W.F.A. Zimmermann, Library of Congress is from 1861. (Image Public Domain)

Animals need space to roam and numbers to survive. Genetic diversity makes a species strong: larger populations means healthier individuals because there is more genetic diversity. For example if there is an odd mutation in the genes passed on to offspring and that offspring doesn’t survive, in large populations, this gene may only be given to a few individuals; whereas in a small population, this gene could kill the species.

The last surviving woolly mammoths showed signs of a ‘genetic meltdown’. On the small desolate Wrangel Island in Siberia, the woolly mammoths survived until just 3,700 years ago (that’s a whopping 5000 years longer than woolly mammoths anywhere else on Earth). Here a small population of these shaggy giants survived, but research examining the DNA has shown that they were full of mutations. Without other mammoths to breed with bringing in fresh DNA, this population was riddled with mutated genes. There isn’t any evidence that these mutations were especially harmful: these Wrangel Island mammoths were a little smaller than their mainland relatives (an example of island dwarfism, which we have seen before with mammoths). It appears that the last of these iconic beasts disappeared shortly after humans arrived on Wrangel Island.

The iconic, shaggy, woolly mammoth. The last surviving species of the great Mammuthus genus vanishing just 3,700 years ago.

DNA is a pretty fragile bunch of chemicals. It breaks apart pretty soon after an organism dies.  For some extinct animals it is difficult to see if mutations dominated a genome, or even had an effect on the last members of a species. Sometimes odd features in an animal might be preserved as a fossil, which provide evidence of a species struggle for survival. A recent study investigating woolly rhinoceros bones looked at just that.

Researchers examined 32 woolly rhino cervical vertebra for abnormalities, specifically looking for signs of rib growth. This may seem for a strange thing to look for, but it can tell us quite a lot. Apart from the wonderfully placid manatees, and the equally docile sloths, all mammals, from giraffes to mice, have seven cervical vertebrae (the neck vertebrae). A genetic mutation can alter the growth in an embryo changing one neck vertebra to grow into a thoracic vertebra (the vertebrae that hold ribs). The research found a particularly high number of ribs which showed this change: 5 out of the 32 specimens. This is an odd result, because it is particularly high for such a small sample. It does and can happen in animals, including humans, and can shorten the life span of the individual with the abnormality. It does happen, but it is rare. So something must have been going on to cause the high incidence of this genetic mutation.

These two woolly rhinoceros cervical vertebrae are almost completely fused, indicating a genetic abnormality in this individual. (Image van der Geer & Galis)

This study looked at specimens from the North Sea and the Netherlands. (The North Sea was once dry and was a rich ecosystem for Pleistocene fauna. Lots of bones of many Twilight Beasts have been dredged up by fishermen over the years, including mammoths, giant deer, and even a Neanderthal skull fragment.) The time span for the 32 specimens is pretty large: they haven’t been radiocarbon dated, but are from deposits dating between 115,000 to 36,000 years old. The results indicate to the authors that the last populations of woolly rhinoceros were under tough conditions, leading to high prevalence of genetic mutations.

Towards the end of the Pleistocene a lot was changing. Temperatures were fluctuating, eventually warming rapidly. The Steppe environment that sustained so many of the familiar giant European mammals was shrinking: removing low lying grasses and shrubs the thick lips of the woolly rhinoceros were adapted to feasting on. Trees and woodlands grew instead. A quick change in environment like this can put stresses on animals (such as lack of food) causing foetuses to be aborted or grow abnormally. A rapidly changing environment would lead to lower numbers of woolly rhinos,  which likely subsequently increases inbreeding (again causing more mutations). Humans did hunt and eat woolly rhino, and may have had an impact on an already shrinking species.

The glorious Woolly Rhinoceros. One of the most underappreciated Twilight Beasts.

What this new research shows is that species are under more pressures to survive than we might think. We know about the effects of climatic fluctuations and habitat loss, but the damage this does internally is devastating to a species genome: Additional stresses on an animal can cause mutations in genes to become fixed and if a population is too small, then it may be the end of that species. We are an oxymoron. Our species is wise and we have a very good understanding of why species have gone extinct in the past, and even see what happens to the genes of animals when the species is put under pressure. Yet…

The last woolly rhinos may have had the loneliest end out of all the Pleistocene mega-fauna. Like rhinos today, they were solitary animals. To find a mate they may have slowly trekked for miles across frozen desolate land, howling wind, and an endless expanse of nothingness. Those last few may have trekked for years, warm breath puffing out of their nostrils as they slowly trundled along, never finding their mate.

Written by Jan Freedman (@JanFreedman)

*******Postscript: In this post I have said ‘we’ throughout when referring to humans. I know that many of us are very proactive and donate and sign petitions to help save a plethora of animals. I have purposefully used ‘we’ for this post, simply because you will relate to it more. You are not someone who is hunting animals or destroying ecosystems. But together we can all do something about it. **************

Further Reading:

Gunthrie, R. D. (2004), ‘Radiocarbon evidence of mid-Holocene mammoths stranded on an Alaskan Bering Sea island’, Nature. 429. (6993). 746-9. [Abstract only]

Jacobi, R. M. et al. (2009), ‘Revised radiocarbon ages on woolly rhinoceros (Coelodonta antiquitatis) from western central Scotland: significance for timing the extinction of woolly rhinoceros in Britain and the onset on the LGM in Central Scotland’, Quaternary Science Reviews. 28. 2551-56. [Abstract only]

Kurten, B. (1968), ‘Pleistocene mammals of Europe’, The World Naturalist. [Book]

Lister, A, & Bahn, P. (2007), ‘Mammoths – Giants of the Ice Age’, (3rd Edition). London: Frances Lincoln. [Book]

Markova, A. K. et al. (2013), ‘New data on changes in the European distribution of the mammoth and woolly rhinoceros during the half of the Late Pleistocene and the Early Holocene’, Quaternary International. 292. 4-14. [Full article]

Stuart, A. J, & Lister, A, M. (2012), ‘Extinction chronology of the woolly rhinoceros Coelodonta antiquitatis in the context of late Quaternary megafaunal extinctions in northern Eurasia’, Quaternary Science Reviews. 51. 1-17. [Full article]

Stuart, A. J. (1982), ‘Pleistocene vertebrates in the British Isles’, Longman Group Limited. [Book]

Sutcliffe, A. J. (1985), ‘On the track of Ice Age mammals’, British Museum (Natural History) [Book]

Van der Geer & Galis, F. (2017). ‘High incidence of cervical ribs indicates vulnerable condition in Late Pleistocene woolly rhinoceroses.’ PeerJ. [Full Article]

Posted in Woolly Mammoth, Woolly Rhinoceros | Tagged , , , , , , , , , , , | 1 Comment

Discovering the mammoth: A tale of giants, unicorns, ivory, and the birth of a new science

Mammoth. With one word, we can all conjure up a mental picture of a woolly elephant, tusks curving out and in, possibly in a herd, in a habitat cold and snowy with biting wind and unforgiving snow. Isn’t it weird? No one living has seen this beast alive. Every detail is the result of centuries of painstaking work, often undertaken with the threat of severe danger either from the frigid lands where the remains are found or from meddling with issues at odds with the ecclesiastical authorities. All it takes is one word, yet behind those two syllables lie a story that starts with the Yakuts and native Siberians and goes on to encompass nearly everyone of note in the western history of science for the past half millennium. Finally, John J McKay has brought this fascinating story to the public in his new book “Discovering the mammoth”. This work tells the tale of Teutobochus the giant, unicorns, monsters, Polyphemus the Cyclops, Tsars, empire building, Kings and Queens, Emperors and Regents, peasants, soldiers, conmen and tricksters all linked together by the mammoth.

I really liked this book*. It is by no means an easy read, with a host of characters, locations, and ideas that flit back and forth, forward and backward, but the enthusiasm present in the writing and the constant appearance of famous names intersecting with the main thrust of the narrative make it all worthwhile. Even for someone with a long history of interest in the history of our understanding of the Pleistocene there is much new here to me, and almost certainly to other readers as well. Who knew that Alfred the Great was presented with mammoth ivory by a swashbuckling and widely-travelled Viking named Ohthere in the 9th century? Or that Ambroise Paré, surgeon to the court of France in the 16th century tested the efficacy of unicorn horn (i.e. mammoth ivory) as a panacea by poisoning condemned prisoners and seeing if they got better**? The book is full of fascinating vignettes like this as we see protagonists struggling to throw off the shackles of superstition, magic, and theology to get to the heart of the mysterious mammoth. There are several appearances by Leibniz, famously co-author of calculus with Newton, who had a very strong interest in mammoth studies. Peter the Great also turns up. Curious about mammoths, he issued a royal edict demanding that anyone finding ivory in Russia should search for the rest of the skeleton for inclusion in his Kunstkamera. Vitus Bering, Hans Sloane, Peter Simon Pallas, Voltaire, Darwin, Cuvier, Buffon, and other luminaries all have cameos. It’s really a testament to the depth of scholarship and the strange pull that mammoth fossils have held over people that all these threads can be pulled together within one book.

The Adams mammoth today at the Vienna Natural History Museum. You can clearly see the mummified skin still attached to the head. Image by Monika Ďuríčková via Wikimedia Commons

There are fascinating discussions of the history of explanations for mammoths. From the 2nd century BC works of the Han Dynasty describing a giant rodent that lives underground and dies on exposure to the air, to medieval European explanations of bones found in caves and under fields as Pagan giants, Hannibal’s war elephants, or elephant bodies washed northwards by Noah’s floods. Anyone at all conversant with modern creationist literature will find it somewhat amusing to see many of their arguments pre-empted (and then discarded) by scholars from the renaissance. McKay’s writing is fluid, and he has a good eye for reading between the lines of his source material. In a chapter that discusses the famous Adams mammoth, the first really complete mammoth known to western science, we see this acutely. Named after Mikhail Adams, a Russian naturalist who found himself in northern Siberia at the right time to take advantage of a recently uncovered mummy (and not after President John Quincy Adams, as I had previously blithely assumed). Here McKay deftly discusses how Adams treated the native discoverer Ossip Schumachov, and other members of the Batouline or Evenki people. Claiming credit (and money) for transporting the mammoth back to St Petersburg, this outraged Schumachov enough for him to make the perilous journey from his homeland to St Petersburg to protest that as the real discoverer, his mammoth was a gift and not an object of trade. He was ignored. There is also the ugly, and previously untold fact that in Mikhail Adams conscription of local labour from the Evenki to excavate the mammoth, a considerable percentage of able-bodied men were diverted from Autumn preparations of hunting and storing food that would see them through the unbelievably harsh winter. These stories are untold, but explain why even a century after Adams visit, local peoples hushed up mammoth discoveries for fear of being pressganged into unpaid labour. It is thanks to details and expositions like these that I unhesitatingly say that this book is definitely worth inclusion on the bookshelf of any student of the ice age.

An Evenki family photo taken in 1900. Public Domain image via Wikimedia Commons

My only major complaint is that this work would massively benefit from a much closer proofreading than it has received. The prevalence of spelling mistakes, and omissions and duplications of words, seriously takes you out of the flow of the text. In the worst example, pages 132, 133, and 134 all have errors that forced me to re-read the text multiple times instead of enjoying the prose. For reference these are Rynochotherium instead of Rynchotherium, gomophthere instead of gomphothere, and vis plasica instead of vis plastica. Factually, I found nothing to fault except a confused discussion of buffalo and bison on page 158. Buffalo, either genera Syncerus or Bubalus, have never been found in the northern latitudes in the mammoth fauna, whereas bison (American buffalo) are plentiful. I think this confusion stems from the selective quotation of works by Gmelin and Pallas and is not McKay’s error but it still left me scratching my head.

*Full disclosure: I received a free copy of this book for purposes of reviewing.

**they didn’t.

Written by Ross Barnett (@DeepFriedDNA)

 

Posted in Cave art, Columbian Mammoth, Deinotherium, Extinction, Mastodon, Palaeoloxodon, Scientific Art, Stegodon, Woolly Mammoth | Tagged , , , , , , , , , | 1 Comment