Smilodons: Awesome Extinct Animals, Pt 5

Welcome to the fifth and final edition of Awesome Extinct Animals.

Today we will be exploring the life and times of an incredible beast that no longer graces the plains and outcrops of  Earth.  They were the Princes of the Pleistocene, Masters of Mayhem, and Lords of Laceration.  They are probably one of the first creatures that come to mind when talking about amazing mammalian predators.

Today’s animals are members of the genus Smilodon: the Sabre-tooth cats.

While popular culture often refers to these creatures as sabre-tooth tigers, the biologist in me insists you call them cats because they are about as tiger-y as lions, leopards, cheetahs, or your house cat.  If you call Smilodon a sabre-tooth tiger, you might as well call Garfield a lasagna tiger.  And that is a disgrace to tigers everywhere, so don’t do it.

There were two species of Smilodon that lived in the Americas during the Pleistocene: Smilodon fatalis and Smilodon populator.  They were quite similar except that where fatalis weighed up to 280kg (620lb), populator was a significantly larger with a max weight of 400kg (880lb).  They had mostly the same physical characteristics and proposed behaviours and so I will treat them as synonymous and refer to both as simply Smilodon.

Smilodon‘s most striking feature was its set of ginormous canine teeth.  Extending well past the lower jaw, the serrated blades could grow up to 28cm (11″, about the length of a typical human forearm). To accomodate these extreme canines, the jaws of Smilodon could open almost 120 degrees.  From a completely scientific protractor-in-mouth experiment I have just conducted on myself, I discovered humans have about 30 degrees and a real study from the University of Nebraska claims modern lions can open their jaws as wide as 65 degrees.

The length of the teeth, combined with their relatively small diameter meant they were somewhat fragile.  Smilidon could not have grabbed and shaken its prey, its teeth would have snapped.  Instead, Smilodon would subdue its prey with its claws and bulk, delivering the coup de grâce with its sabres.  It would sink the blades into the doomed soon-to-be-dinner and since the inside edges of the teeth were serrated, it could easily rip out huge chunks of flesh.

We happen to know a whole lot about Smilodon because of a handy-dandy death trap known as the La Brea Tar Pits, in Los Angeles.  Because of the city’s location on a fault, oil and tar have been bubbling up into a pit for hundreds of thousands of years.  The incredibly sticky and toxic substance has been collecting and preserving animal bones ever since.  Unfortunately the animals in question have little choice in the matter.  Hundreds of unlucky Smilodon wandered into the pit between 2.5 million and 10 thousands years ago.  Now, hundreds of lucky Homo Sapiens get to learn a lot about Smilodon ecology, anatomy, and behaviour.

Smilodon was thought to be an ambush predator, using its bulk, strong forelimbs, and incredible canines to subdue and kill prey before it could escape.  Smilodon would not have been able to chase its prey for any long distance and so needed cover from which to pounce.  It is thought that this commitment to strength over stamina may have led to Smilodon‘s downfall as the climate changed 10 000 years ago.  Much of the cover disappeared and many of the large, slow herbivores died out, leaving only nimble long-distance runners like deer as prey items.  Smilodon could not keep up and competitors like wolves and pumas took the last of the available food.  Smilodon petered out and the latest fossils found are from 10 000 years ago, marking the end of the age of large ice age predators and the beginning of the rise of Homo sapiens civilization.

Sources:

http://en.wikipedia.org/wiki/Smilodon

https://en.wikipedia.org/wiki/La_Brea_Tar_Pits

Andersson, K., Norman, D., & Werdelin, L. (2011). Sabretoothed carnivores and the killing of large prey. PloS one, 6(10), e24971. doi:10.1371/journal.pone.0024971

Martin, L. D. (1980). Functional Morphology and the Evolution of Cats. Transactions of the Nebraska Academy of Sciences and Affiliated Societies, 3, 141–154.

A great BBC Documentary series that just started:

Ice Age Giants, Episode 1: Land of the Sabre-tooth  http://www.youtube.com/watch?v=5veLxFRLrsE