National Fossil Day: The Big Cats of Pleistocene Park

 Today, October 12, 2016, is National Fossil Day™, an effort by the National Park Service to promote public awareness of fossils and to highlight fossils’ scientific value. This year’s theme is “Pleistocene life and landscapes.” Imagine, if you will, a place called Pleistocene Park covering all of North America. We think this would be way better than that old Jurassic thingamabob, because there would be so many different kinds of big cats. By the way, in case you are as clueless as we were about what “Pleistocene” means, it’s basically the period from about 1.6 million years ago to 10,000 years ago. The following list of big cats of the North American Pleistocene is organized by genus and species.

Genus Dinofelis

These cats, known as “false saber-tooths” because the form of their teeth was something between a saber-tooth and that of modern species, were between a leopard and lion in size. Their fossils have been unearthed in Pleistocene deposits in Eurasia, Africa, and North America.

Genus Homotherium

Human, meet Homotherium. Obviously, this was not
a cat you'd want to keep in your cave. They'd be
perfect for Pleistocene Park, though.
By Dantheman9758 at English Wikipedia [CCBY 3.0], via WikimediaCommons.

These were lion-sized saber-toothed cats known from 3 million to 10,000 years ago in North American. In Friesenhahn Cave in Texas, an articulated skeleton (H. serum) was discovered, along with the remains of over 30 individuals, including cubs. The teeth of several young mammoths were also found there, which could be evidence that the cats specialized in preying on mammoths.

Genus Panthera

Panthera onca

This is your basic jaguar, and yes, they are known from the Pleistocene, when they ranged well into North America (up to Washington State). I say “your basic jaguar,” though the Pleistocene cats seem to have been larger than the modern variety. They have been found mostly where lions were not common, in today’s Florida, Texas, and Tennessee.

Cast of Panthera atrox skull. A skull like this could
have belonged to a lion in our Pleistocene Park.
By Claire H. from New York City, USA [CC BY-SA 2.0 ],
via WikimediaCommons. 

Panthera leo

Yes, there would be honest-to-goodness lions in our North American Pleistocene Park. Some scientists consider the American lion (P. atrox) its own species.

Panthera tigris

Tigers were also around in the Pleistocene, and they might have crossed the land bridge from Asia into North America, thus entering our park.

Genus Felis

Felis concolor

Some of you may recognize this as the scientific name of the mountain lion, otherwise known as the puma or cougar. These cats are known only in the Americas, and they appear in the fossil record from about 500,000 years ago.

Genus Miracinonyx

These cats were similar to modern cheetahs and may have been a primitive form of cheetah. The genus is known in North America from fossil remains of two species, M. inexpectatus and M. trumani. The older M. inexpectatus, from about 3.2 million years ago, is out of the time range of our park, but M. trumani was from 10,000–20,000 years ago, so they’d fit in nicely. Their bones were similar to those of modern cheetahs, but their claws were more fully retractable (modern cheetahs have semi-retractable claws).

In case you're wondering, here you can see the
relative sizes of the three Smilodon species.
That blue man should stop waving and start running!
By Matthew Martyniuk, adapted from 2001 original
by Walking with Beasts (Own work) [GFDL], via Wikimedia Commons. 

Genus Smilodon

And so we come to perhaps the most famous of the Pleistocene cats, the saber-toothed cats of genus Smilodon. These cats are known from North and South America, and the last of them became extinct about 10,000 years ago. In the famous La Brea Tar Pits of California, at least 12,000 individuals have been found.

Three species are recognized:

1. S. gracilis was the smallest and earliest (2.5 million to 500,000 years ago) of the three. They lived in what is today the eastern United States.
2. S. populator was the largest (the size of a modern lion). They are known from eastern South America, and they had huge upper canines.
3. S. fatalis, the species that would be appropriate for our park, fell between the other two in size. They are known mostly from Pleistocene deposits in North America, though they have also been found in South America. When you think “La Brea Tar Pits” (or "Pleistocene Park"), think “Smilodon fatalis”!

And what would a story about Pleistocene cats be
without a saber-toothed cat skull? This one is
Smilodon fatalis.

By James St. John [CC BY 2.0], via Wikimedia Commons.

We hope you've enjoyed this brief journey to meet the cats of Pleistocene Park. We really did not know there were so many species of big cats way back then, and they weren't all saber-toothed. Thanks to National Fossil Day, now we know!

Want more prehistoric cats? See Meet the Cat of All Cats: He's 25 Million Years Old and How Long Did It Take for a Saber-Toothed Cat to Grow Its Saber Teeth?

Source

Alan Turner, with illustrations by Mauricio Antón, The Big Cats and Their Fossil Relatives (New York: Columbia University Press, 1997).

If you are in to big prehistoric cats at all, I think you’ll find this book an excellent reference. The paperback is reasonably priced, it’s readable, and it’s heavily illustrated, including 16 color plates. Highly recommended!

The link below is an Amazon Associates link. If you purchase the book through this link, old SoLT and I could get some coin for our kibble account.