Ancient ‘otter bear’ may have popped clams off rocks like a bottle opener

Roman Uchytel

Ancient ‘otter bear’ may have popped clams off rocks like a bottle opener

A creature that roamed the coasts of the Pacific Northwest about 20 million years ago may have had a feeding style like no other mammal, a new study suggests. Kolponomos is known only from two bearlike skulls, jawbones, and some toe bones found a few decades ago, so scientists aren’t sure where it fits on the carnivore family tree or even what it really looked like (one artist’s idea is seen above). Rather than having cheek teeth that could shear meat, as many carnivores do, Kolponomos’s molars were similar to the flattened, low-crowned teeth that otters use to crush their shelled prey—yet the creature lived long before anything similar to modern-day otters evolved. Now, a new analysis using the same sort of computer software that engineers employ to analyze bridges and aircraft parts suggests that Kolponomos may have collected its shelly prey in a unique way: They might have used their teeth and formidable neck muscles to clamp down on clams, mussels, and other mollusks and then wrench them directly off the rocks to which they were attached, the researchers report online today in the Proceedings of the Royal Society B. (Modern marine mammals that consume such prey either slurp them right out of the shell, as walruses do, or pry them from the rocks using their forelimbs and then eat them, as otters do.) Besides having a larger-than-normal chin, a deep jawbone, and massive neck muscles even larger than those of today’s bears, Kolponomos had odd grooves worn into the outer surfaces of the large canine teeth at the front of the lower jaw. With its lower canine teeth wedged firmly into place beneath a shell, Kolponomos could have braced its chin on the underlying rock, clamped down on its prey, and then popped it off the rock like a bottle opener. And although otters experience large stresses in their jawbones when crushing shelled prey, Kolponomos, whose jawbone was relatively longer and wider, likely didn’t have as much trouble.

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