Smilodon Claw Anatomy – Sabre-Tooths Great at Climbing but Rubbish at Descending

The Sabre-Tooth cats more appropriately termed Smilodons are one of the most enigmatic of prehistoric mammals from the Quaternary.  Thanks to the remarkable fossil sites such as tar pits of Rancho La Brea, Los Angeles, California, a large volume of Sabre-Tooth fossil remains have been excavated.  Most of the Sabre-Tooth cat fossils have been identified as belonging to S. fatalis californicus, but it is not just the volume of fossils that is important, many specimens have been preserved in pristine condition.

The tar pits have formed as crude oil has seeps through fissures in the rock strata to the surface.  Water gathers on these pools of sticky, viscous oil and animals mistaken these pits for water holes get stuck.  These attract predators such as Dire Wolves and Sabre-Tooths and these animals share the same fate as the herbivores.

Some of the Everything Dinosaur team members were in Los Angeles and got the chance to examine some of the latest fossil finds.  The pits are trapping animals all the time, sometime earlier that morning a small bird had become stuck and died, the latest victim of La Brea.

More Sabre-Tooth remains have been found at Rancho La Brea than the rest of the world put together which is quite remarkable considering the extensive range of the Smilodon genera across the Old and New Worlds.  Once an animal had become trapped in the tar, it would have quickly sunk, so quickly that skeletons can be preserved with their bones in close association or even articulation.  Rapid burial without scavenging is one of the most effective methods of ensuring preservation.  Even pieces of skin and tufts of fur have been preserved in the tar.  The tar is a natural preservative preventing normal decay.  So well-preserved are the Smilodon remains that even the most delicate and fragile bones such as those within the inner ear are preserved, often intact.

To date something like sixty different species of mammals and thirty-five species of birds have been identified, even human remains have been found.  The fossils date from between 40,000 years to about 10,000 years ago.

Thanks to these fantastic fossils and the dedicated staff who uncover them a great deal is known about Smilodon anatomy.  The Sabre-Tooths that roamed California 10,000 years ago did not resemble modern members of the cat family (Felidae).   These animals were about the size of an African Lion (Panthero leo) but with a much stockier build.  They may have weighed up to twice as much as a modern Lion.  They had shorter limbs, a deep, barrel like chest and a bob-tail.  The forelimbs were massive and heavily muscled, much stronger than the hind-limbs.  This indicates that Sabre-Tooths were ambush predators, they were not built for pursuit of prey animals but used their extremely powerful front quarters to bring down quarry.

The fossil specimens demonstrate that these big cats had retractable claws, in common with most members of the cat family including the domestic cat (Felis silvestris catus).  The Sabre-Tooth claws were long and re-curved in shape making them the animals most formidable weapons, ideal for spearing the body of prey and holding on enabling the victim to be pulled down to the ground, for despatching with those massive canines, which would have severed arteries in the neck.  Smilodon like a domestic cat could also dig its claws into the skin further by closing the extended claws, much in the same way as we might close our fingers around an object when we pick it up.  This would dig the points of the claws further into the animal’s hide and make escape much more difficult.

Sabre-Tooth cats were fierce predators and likely to have hunted our ancestors, however, children remain fascinated with them and the Sabre-Tooth cat appears regularly in our top ten prehistoric animal surveys.

To see the latest survey results: Best Selling Prehistoric Animals 2007/8

Despite its fearsome reputation, young children seem to be fascinated with this big cat.  It has had a recent episode of Primeval dedicated to it and it has appeared in a number of cartoons and other features, Fred and Wilma Flintstone even had one as pet.  When the wooden prehistoric animal jigsaw range was being designed as well as the Woolly Mammoth and Woolly Rhino, a Sabre-Tooth cat jigsaw had to be included as well.

The Wooden Sabre-Tooth Cat jigsaw: Dino Board Games and Puzzles

Although as a genus, the Sabre-Tooths are not entirely associated with the Ice Ages, these animals also thrived in temperate grassland areas.  For example, Smilodon populator is known from several sites in Brazil, Argentina and Bolivia and some fossil remains have been dated to over 1.5 million years ago.  This particular species, even larger than its North American cousin hunted the grasslands of South America preying on herbivores such as Macrauchenia.  Macrauchenia was a distant relative of modern ungulates (hoofed animals), with a distinctive trunk on the end of its nose to help it browse on grasses and low growing bushes.

To see a model of Macrauchenia and other prehistoric animals: Dinosaur Toys for Boys and Girls – Dinosaur Models

This ability to close the claws and dig the points further in may also have helped smaller Sabre-Tooths climb.  It is unlikely that a fully grown, heavy adult would do much climbing but there is no evidence in the fossil record to confirm or deny that Sabre-Tooths climbed.

Certainly, the anatomy of the claws and manus (the hand) permit Sabre-Tooths to climb objects like trees should they have wished to do so.  Domestic cats are very effective climbers and can scurry up trees with no problem at all.  However, this arrangement of the claws being able to “grasp” is excellent during the ascent and provides plenty of purchase, leverage and grip.  The trouble comes when the cat wishes to descend.  Claws when deployed in the descent of a tree provide very little grip.  This explains why your local moggy can run up a tree one minute and then get stuck having to be rescued as they cannot get down without risk of falling.

The anatomy of the claws of Sabre-Tooths also shows that they suffered from this design drawback.  Should one have climbed a tree, perhaps looking for prey or to avoid being attacked by another predator, then they would have struggled to get down again.  Perhaps they would jump, landing on their powerful front quarters using them to cushion the shock on landing.  For a small Sabre-Tooth climbing up a tree getting down again could be hazardous, after all, in the Pleistocene they could not wait for the fire brigade to rescue them.

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