Teeth of some apes are formed primarily to survive toughest times

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Washington, December 18 (ANI): A new research has determined that the teeth of some apes are formed primarily to handle the most stressful times when food is scarce.

The research, performed by scientists at the National Institute of Standards and Technology (NIST), imply that if humanity is serious about protecting its close evolutionary cousins, the food apes eat during these tough periods-and where they find it-must be included in conservation efforts.

The interdisciplinary team, which brought together anthropologists from George Washington University (GWU) and fracture mechanics experts from NIST, has provided the first evidence that natural selection in three ape species has favored individuals whose teeth can most easily handle the "fallback foods" they choose when their preferred fare is less available.

All of these apes-gorillas, orangutans and chimpanzees-favor a diet of fruit whenever possible.

But, when fruit disappears from their usual foraging grounds, each species responds in a different way-and has developed teeth formed to reflect the differences.

According to GWU's Paul Constantino, "When resources are scarce, that's when natural selection is highly active in weeding out the less fit, so animals without the necessary equipment to get through those tough times won't pass on their genes to the next generation."

In this case, the necessary equipment is the right set of molars.

The team examined ape tooth enamel and found that several aspects of molar shape and structure can be explained in terms of adapting to eat fallback foods.

For instance, gorillas' second choice is leaves and tree bark, which are much tougher than fruit, while orangutans fall back to nuts and seeds, which are comparatively hard.

For these reasons, the researchers theorized that gorillas would have evolved broader back teeth than a fruit diet would require in order to chew leaves, but orangutans would have thicker enamel to handle the increased stress of crunching seeds.

NIST scientists developed models of how teeth fracture while chewing different foods.

By fracturing teeth in the laboratory, they verified fundamental fracture mechanics models incorporating tooth shape and structure.

These efforts revealed the effects of food stiffness and how various foods likely would damage ape teeth.

"The research at NIST supports our theories and several related ones. It's likely that fallback foods have influenced jaw and skull shape as well," said Constantino. (ANI)

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