The sabre tooth is an adaption so advantageous it independently evolved at least five separate times in ancient mammals. Now, new research has discovered predators developed these giant canines because they perfectly targeted large prey found at the time.
These teeth were very specific in shape — extremely long, round, and often curved with sharp edges. They balanced sharpness to puncture flesh with being robust enough so they didn’t break.
But conditions have changed over millions of years and that means they no longer provide the hunting advantage they once did. Research published in the journal Current Biology found each species that grew these distinctive thick, long teeth became a highly effective hunter in its heyday. But it’s believed the adaption would eventually become its downfall because once ecosystems changed and large prey became scarce, this niche specialisation left them struggling to adapt.
Lead author and Bristol University senior research associate Dr Tahlia Pollock explained to Yahoo News modern terrestrial mammals use their teeth in a very different way to ancient predators.
“Something like a lion or a tiger, their canine teeth are quite stout and sharp. The way that modern cats kill is to bite the neck or the face and then hold on with a really strong bite until its prey suffocates,” she said during a recent trip to Melbourne.
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The tooth structure perfectly targeted large prey found at the time. Source: Dr Tahlia Pollock
Pollock believes we are unlikely to see a similar adaption in the near future because megafauna is less abundant, and modern-day cats are successful in their hunting techniques.
“You’d have to have quite a few environmental changes for sabre tooth to pop up again. It’s possible but it would take millions of years,” she said.
What are the most extreme examples of sabre teeth?
Pollock’s research was a collaboration between Monash University and the University of Bristol where she is a research associate at the School of Earth Sciences. The team created large 3D models and used computer modelling to analyse the performance of 95 carnivorous mammal teeth from 25 species.
Monash University’s Professor Alistair Evans said the research would increase our understanding of evolutionary biology and biomechanics. “Insights from this research could even help inform bio-inspired designs in engineering,” he said.
Smilodon is perhaps the most well-known sabre-toothed mammal. Source: Getty
The first animals known to evolve sabre-teeth were gorgonopsids, mammal-like reptiles that lived 250 million years ago in modern-day Africa and Russia. One of the most extreme adaptions was discovered in Barbourofelis fricki, a lion-sized mammal that lived in North America and Eurasia 15 to 7 million years ago.
Sabre-teeth popped up again 10 million years ago in marsupial-like Thylacosmilus and then in Smilodon which lived as recently as 10,000 years ago, when humans also roamed the Earth.
What extreme tooth adaption do we see today?
While sabre-toothed predators are all extinct, there are other extreme tooth adaptions still around today.
“There are some pretty extreme teeth still around. One example is the tusks of elephants, and they’re actually incisor teeth,” Pollock said.
“In elephants, these oversized tusks help them in defence, like male-to-male combat, but are also used in display. Females have them too, but they’re not as big, and we know they’re used to forage in their environment. They’ll use them for digging, trying to expose roots, or stripping bark off trees.”
Another extreme example is the narwhal, a species of toothed whale native to the Arctic that grows a 1.5 to 3-metre spiral-shaped tusk on its head.
“It almost has a unicorn-horn quality to it. We know much less about what they do with their tusks. Hypotheses are related to social and reproductive signalling. There are also some hypotheses that they could help them to sense different aspects of their environment. Then there are traditional ideas that the tusk helps them to hunt or immobilise prey.”
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