Sharp As a Sabre

Vet Times The website for the veterinary profession https://www.vettimes.co.uk

Sharp as a sabre

Author : Vicki Brown, Harry Brown

Categories : General, Vets

Date : October 31, 2016

”Sabre-toothed” may put images of tigers in your head. However, sabre teeth have evolved at least four times in mammals, but never in a tiger.

Smilodon populator.

Sabre-toothed marsupials and other sabre-toothed cat-like animals – the extinct nimravids and creodonts – have existed, but the most well known are the sabre-toothed cats, often confused with tigers. Properly known as the Smilodon genus, they were distantly related to today’s big cats and lived in the Americas during the Pleistocene era 2.5 million to 10,000 years ago.

The most obscure member of the Smilodon genus was the small Smilodon gracilis. The North American Smilodon fatalis was slightly bigger and regularly crossed paths with the dire wolf. The South American Smilodon populator was the most imposing sabretooth of them all, with the males weighing as much as half a ton. The S populator’s huge, curving canines measured close to 12in.

As most modern big cats are pack animals, palaeontologists have thought sabretooth cats lived (if not hunted) in packs as well. One piece of evidence supporting this premise is many Smilodon fossil specimens bare evidence of old age and chronic disease – it’s unlikely these debilitated

1 / 3 individuals would have been able to survive without help from other pack members.

The long, brittle canines of the sabretooth cat, combined with its weak jaws, point to a highly specialised hunting style. As far as palaeontologists can tell, Smilodon pounced on prey from low tree branches, plunged ”sabres” deep into the neck of unfortunate victims and withdrew to a safe distance (or perhaps back into a tree) as the wounded animal eventually bled to death.

Some house or small, wild cats kill prey with a bite to the back of a victim’s neck, which is broken by the predator’s canine teeth. This would seem an interesting explanation for the sabre teeth – large cats, killing large prey, have large canines to break their victims’ necks with. But there’s a problem. The sabres are delicate – any contact with bone and they would shatter, never to grow back again.

Accurate bite

Large cats, such as lions, strangle their prey by biting the throat and holding the trachea closed. This would be a better way to use sabre teeth. With an accurate bite, the sabres would accelerate the death of the prey. As the cat closed its mouth on the neck of its victim, the sabre teeth could have punctured the major blood vessels to the brain, as well as closing off the windpipe, quickly killing the animal. However, for this to work, the cat had to be able to first subdue the struggling prey so it did not put its delicate teeth at risk.

Smilodon had several adaptations that may have helped them kill in this way. First, they had very powerful forelegs with sharp retractable claws, which would have helped them bring their prey to the ground and hold it still so as to get an accurate bite. Then their skull shows a very large nerve supply to their whiskers, which would have helped them find exactly the right place to bite, just as modern cats’ whiskers do.

Finally, their front teeth stuck out slightly, allowing them to strip meat from carcases without their sabre teeth getting in the way. The wear patterns on Smilodons’ teeth show they avoided bone almost entirely – probably to protect their huge sabres – with the result it would leave plenty of meat for scavengers on the plains.

Most dinosaurs and prehistoric animals are discovered in remote areas of the US, but not the Smilodon, specimens of which have been recovered by the thousands from the La Brea Tar Pits of downtown Los Angeles. Most likely, the S fatalis individuals were attracted to animals already stuck in the tar and became mired hopelessly themselves in their attempt to score a free (and seemingly easy) meal.

Aside from massive canines, there’s an easy way to distinguish the Smilodon from a modern big cat. The Smilodon build was comparatively robust, including a thick neck, broad chest and short, well-muscled legs.

2 / 3 This has a lot to do with this Pleistocene predator’s lifestyle; since Smilodon didn’t have to pursue their prey across endless grasslands, they evolved in a more compact and less sleek direction.

Why did the sabretooth cat vanish off the face of the earth at the end of the last ice age? It’s unlikely early humans had the brains or the technology to hunt Smilodon to extinction; rather, it was likely a combination of climate change and the disappearance of this cat’s large-sized, slow-witted prey.

References

Haines T (2001). Walking with Beasts, BBC Books, London. Strauss B (2016). 10 facts about the saber-tooth tiger, About Education, http://dinosaurs.about.com/od/otherprehistoriclife/ss/10-Facts-About-the-Saber-Tooth- Tiger.htm University of California Museum of Paleontology (1994). What is a sabertooth? www.ucmp.berkeley.edu/mammal/carnivora/sabretooth.html

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