Abya Yala was the land of dogs for a long time.* This is where they evolved. On a solitary, large landmass drifting through a vast ocean. A landmass that Europeans would later call North America. These very familiar animals evolved around 20 million years ago, where they gave rise to a huge number, and huge variety, of different species.
The family of dogs is much bigger than just our friendly pets (although the variety within our beloved pets is enormous!). They were once a very diverse, very successful, group of carnivores, and are still diverse and successful today. Of the three different families of canids that have lived (the Hesperocyoninae, Borophanginae, and Caninae), only the Caninae survive.
Today, there are 27 different species of canids across the world, including wolves, numerous species of foxes, bush dogs, and of course our pets. They are familiar animals to us (the scientific name for our household dogs is Canis familiaris) and as a family, they have been around for quite some time, evolving around 34 million years ago. They lived solely in Abya Yala, until around 8 million years ago when they moved across the Berinigia land bridge, and into Asia, Europe and Africa.
It wasn’t until around the start of the Pleistocene, around 2.6 million years ago, that canids made their way to South America. This equally large landmass was separated from North America, until around 3 million years ago when under water volcanoes, and huge deposits of marine sediments built up and formed the Isthmus of Panama. A connection linked these two lonely landmasses together for the first time in over 200 million years. They didn’t so much as find each other, rather, the natural movements of our planet brought them together: two lost souls connected at last.
When animals can move easily across land, they will. And they did. They moved across the Isthmus of Panama in their thousands. Animals from South America, like the giant glyptodonts, terror birds, and giant sloths, moved into North America, and animals from the north, like the sabre tooth cats, tapirs, camels and horses moved south. In this mass exchange of wildlife, species of canid also moved down into this new land. And here they flourished. New environments provide new opportunities.
Although canids have been in South America for a relatively short period of time, this is where they are most diverse. There are ten different species living there today. Several are commonly called foxes, only they are not the same species as the familiar red fox we know, only superficially looking like them. There’s also the rather leggy manned wolf (not a wolf, but a completely different genus, but it does have very long legs). And the bush dog, which looks like a cross between a weasel and a miniature bear.
Once canids arrived in South America, they quickly spread and new species evolved. Dozens of species roamed the land during the Pleistocene. One of them was a top carnivore in this new, unexplored land. Discovered in 1891, Theriodictis platensis was one of the largest canids in South America, about the size of a German Shepherd, and it was well adapted to hunting large prey. There were several other large predators in South America along with T. platensis, including several other canid species, the sabre tooth cat (Smilodon populator), jaguars (Panthera onca), pumas (Puma concolor) and the giant short faced bear (Arctotherium angustidens). The Isthmus of Panama brought a whole melange of new predators with it.
Fossils of T. platensis have bene recovered from rocks in the Buenos Aires province of Argentina, Bolivia, and southern Brazil. It was relatively widespread, but restricted to the central areas of South America. Associated fossils indicate that this large canid was living on grasslands, hunting camels, horses, deer, and other large herbivores. Their jaws and skulls show that large muscles would have attached, giving this canid a very strong and powerful bite.
This bite may have been powerful enough to crunch through the armour of the mighty glyptodon. Some researchers suggest that these armadillo tanks evolved even more protection after the arrival of these new predators. The range of new carnivores that moved into South American likely pushed this defensive evolution. Isolated bony plates (osteoderms) have been found, which indicate that they were on glyptodonts, but not attached to the main shell. This hints that these isolated osteoderms were to protect the more exposed areas on the body, particularly around the neck. That these new predators caused fairly rapid changes in already well armoured giants, shows that they were quite formidable beasts. This is not all bavardage. At least one glyptodon fossil shows evidence of being attacked by a large predator, which was most likely Theriodictis platensis.
The majority of fossils come from rocks that date to the Middle-Late Pleistocene, around 780,000 – 500,000 years ago. A small number of specimens have been found in older rocks which date to around 1 million years ago. When it comes to extinct species, we can only gauge their span on the planet by the fossil we have found. Fossils of T. platensis show it was around for around just 500,000 years. More fossils in older and younger rocks may show that it was around for longer, but for the minute we know it was on our planet, hunting large herbivores for around half a million years. And then it vanished. We don’t know why. Competition from other predators? Changing environments? Changing climate? One of the great things about palaeontology is that there are still so many questions that will be answered. Sometimes it through new discoveries and fossils. And sometimes the answers are found in collections in museums. It just takes a fresh look at some old bones.
*Postscript: Abya Yala is the name given to the land lived on by indigenous native people. This land was named ‘America’ after Europeans colonised the land. In the late 1490s, it was coined by the German cartographer, Martin Waldseemüller, after the Italian explorer Amerigo Vespucci. Although Abya Yala is used by the Guna people of Panama and Colombia, it is also used by several indigenous groups to describe the continent. In the Guna language it means “land in its full maturity” or “land of vital blood”.
Written by: Jan Freedman (@JanFreedman)
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Hi! Nice text, I enjoyed a lot (:
I recommend to you to read Zrzavy et al., 2018, (Phylogeny of the Caninae (Carnivora): Combining morphology, behaviour, genes and fossils). This paper brought a new light to phylogeny questions, like the actual number of extant canids species.
I hope you’ll like!