New Rat Species Is Nearly Toothless

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A new species of rat that has practically no teeth has been discovered. But no worries, the rat hardly needs them since it feeds on a diet of soft earthworms.

The rat, dubbed Paucidentomys vermidax, is a type of shrew rat that lives on Sulawesi Island in Indonesia. It’s the first known rodent to lack cheek teeth.

The rat is missing all of its molar teeth, and instead only has incisors. While the rat’s “smile” is hard to see (and maybe there’s not much to smile about in the tough rodent world), it looks buck-toothed, due to the presence of just these larger front teeth.

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Jacob Esselstyn of McMaster University and colleagues point out that all other known rodents — and there are some 2300 species — retain a lot of teeth. The choppers are needed to munch on all of the diverse things that rodents eat, such as seeds, grasses and even other smaller animals.

Food explains why this new rat is nearly toothless.

“Because of the unique shape of its incisors it cannot gnaw, and it appears to feed exclusively on earthworms,” Esselstyn and his team wrote.

“This species illustrates how the process of evolution can lead to the reversal of previously successful traits when faced with new opportunities,” they added.

Their study is published in the latest issue of Biology Letters.

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If humans only existed on power drinks in future, we might then also evolve mouths without teeth. It’s also interesting, and a little creepy, to think how today’s often very sedentary lifestyle could affect human evolution in future.

Some studies even suggest that related behaviors can affect long-term physical appearance within our lifetimes. For example, a lot of sitting supposedly can make your butt look bigger.

(Image of Paucidentomys vermidax: David Paul, Kevin Rowe)