Carnivore canines evolved to kill and eat prey, study finds

Researchers have shown how evolution shaped the teeth of carnivores into unique forms specialised to match their diet and the behaviours they use to kill.

Contrary to popular belief not all canines are created equally.

A new study by researchers at the Monash University School of Biological Sciences and published today in the Zoological Journal of the Linnean Society shows for the first time that canines display important variations that helps each species eat their favourite prey.

Carnivores - animals that hunt and kill their prey - are some of nature's most iconic and unusual animals, ranging in size from lions to quolls.

But one thing they all have in common is a set of sharp fang-like teeth at the front of their jaws.

“These teeth, the ‘canines’, are the main tools used to stab, kill, and dismember their prey,” said lead study author PhD candidate Tahlia Pollock.

“They are the first point of contact between predator and prey and play a vital role in carnivore feeding.”

The research team applied state-of-the-art 3D methods to measure the shape of canine teeth from more than 60 predators, including lions, hyaenas, dingoes, polar bears, and even Tasmanian devils and quolls.

They were able to show how evolution shaped the teeth of these hunters into unique forms specialised to match their diet and the behaviours they use to kill.

“We can see their ecology born out in their teeth,” said Tahlia.

“For example, big cats have long sharp dagger-like teeth, and this helps them to bite deeply into their prey, while animals that scavenge, like hyaenas, have robust teeth that are less likely to break when crunching bone,” she said.

“It’s not just the large iconic predators that show this pattern, we can see it across the breadth of mammalian carnivores.”

The crab-eating mongoose was found to have strong blunt canines that helped to break the exoskeletons and hard shells of its prey, while the red fox used its curved canines to snap up and shake small prey.

When you are in the kitchen, you use different knives depending on what you want to cut, like fish or bread or meat.

“It’s the same with canine teeth, depending on the types of food a predator regularly bites into the best shaped tooth for the job will vary,” said Associate Professor Alistair Evans, a co-author of the study, also from the School of Biological Sciences.

This method can also be used to look at the diet and killing behaviour of extinct carnivores like the Thylacine, which has curved canines which are associated with living predators that to snap up and shake smaller prey. This supports recent research on Thylacine skull shape.

“This is a really cool result because it means that Thylacine skulls and canine teeth are telling us the same story,” Tahlia said.

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