How have saber-toothed animals evolved multiple times?

Predators have evolved saber teeth many times throughout the history of life. And now we have a better understanding of why these teeth develop the way they do.

Saber teeth have very special characteristics. Very long, sharp canine teeth that tend to be slightly flat and curved rather than round. Such teeth have evolved independently at least five times in different groups of mammals, and fossils of saber-toothed tiger predators have been found in North America, South America, Europe, and Asia.

These teeth were first known to appear in mammal-like reptiles called gorgonopsians about 270 million years ago. Another example is Thylacosmiluswhich became extinct about 2.5 million years ago and was most closely related to marsupials. Saber teeth were last seen Smilodonoften referred to as the saber-toothed tiger, existed until about 10,000 years ago.

To find out why these teeth continued to re-evolve, Talia Pollock and colleagues from the University of Bristol, UK, examined the canine teeth of 95 species of carnivorous mammals, including 25 species of saberodonts.

First, the researchers measured, classified, and modeled the shape of the teeth. They then 3D printed a smaller version of each tooth in metal and tested its performance in a puncture test in which the teeth were mechanically pushed into a gelatin block designed to mimic the density of animal tissue.

This showed that the saber teeth could drill into the block with up to 50% less force than the other teeth, Pollock said.

The researchers then evaluated the tooth shape and puncture performance data using a measure called the Pareto rank ratio. This determines how optimal the tooth is in terms of strength or puncture.

“Carnivores’ teeth need to be sharp and thin enough to pierce the flesh of their prey, but they also need to be blunt and strong so they don’t break when the animal bites,” Pollock says.

i like animals Smilodon It had very long saber teeth. “These teeth probably appeared over and over again because they’re the perfect design for puncture,” Pollock says. “They’re very good at drilling holes, but that also means they’re a little more fragile.” For example, California’s La Brea tar pits have Smilodonsome broken tooth.

Other saberodonts also had teeth shaped ideally for slightly different tasks. cat Dino Feliz According to Pollock, they had squatter saber teeth for a more even balance of sting and strength.

The teeth of other saber-toothed species fall between these optimal shapes, which may be why some saber-toothed teeth did not last very long. “These are trade-offs,” Pollock said. “Aspects of the shape of your teeth make you good at some things and bad at others.”

One of the leading theories as to why the saber-toothed tiger species went extinct is that the ecosystem changed and the large prey that the saber-toothed species, such as mammoths, were thought to have gone after disappeared.

The team’s blowout findings support this. Giant teeth would not have been as effective in catching prey as large as rabbits, and the risk of tooth breakage here may have increased, making saber-tooths more effective prey. would have been defeated by someone. Pollock says it’s difficult to hunt prey like cats with small teeth.

“As ecological and environmental conditions changed, highly specialized saber-toothed tiger predators quickly became unable to adapt and went extinct.” Stefan Lautenschlager At the University of Birmingham, UK.

“I think that’s part of the reason why this saber-toothed form hasn’t evolved again now. We don’t have megafauna,” he says. Julie Michen At Des Moines University, Iowa. “The prey isn’t there.”