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# A Jurassic Otter Wasn't Quite a Mammal. Its Throat Didn't Get the Memo.
- URL: https://www.gottabekidding.me/a-jurassic-otter-wasnt-quite-a-mammal-its-throat-didnt-get-the-memo/
- Published: 2026-10-23T10:02:00.000Z
- Updated: 2026-10-23T10:01:59.000Z
- Description: The neck bones that let babies nurse turned up early, in a hunter that swam among dinosaurs. What was a not-quite-mammal doing with them?
- Author: Vitals
- Tags: Nature

Some 165 million years ago, an animal with platypus-style back feet and a wide, flat tail appears to have paddled after prey in what is now Inner Mongolia. It also swallowed much the way you do. One tidy mouthful at a time.

Its name is Megacauda sungei, which translates to big tail. It belongs to the docodonts, an extinct branch of close mammal relatives that lived alongside dinosaurs. Measuring between 40 and 50 centimeters (about 16 to 20 inches) and weighing 1 to 2 kilograms (2.2 to 4.4 pounds), it was built for water, with long outer toes on its hind feet and broad tail bones for pushing itself along.

The surprise is in its neck. Megacauda holds the oldest known sign of mammal-style hyoid bones, a bony U-shaped saddle slung from the skull on a chain of tiny segments. Every modern mammal, including you, has this setup. It lets throat muscles send chewed food down in manageable portions, where an alligator gulps prey whole. The same hardware lets newborns nurse.

University of Chicago biologist Zhe-Xi Luo, the study's senior author, called the apparatus a major evolutionary innovation. Once early mammals could swallow efficiently, he said, each group was free to evolve specialized teeth and branch into meat, plants, insects or anything in between.

Megacauda suggests that throat was assembling itself well before the split that produced modern mammals. Its teeth are odd too. It had sturdy canines plus slicing cheek teeth that cut meat differently from living meat-eating mammals. Flecks of vertebrate bone in its gut suggest it ate small animals, possibly the salamanders common in the same rock.

It hunted, swam and swallowed like a mammal, with dinosaurs for neighbors. Tough neighborhood for a swimmer that topped out around 2 kilograms (4.4 pounds).

**Read the full story at** [University of Chicago, October 7, 2026](https://news.uchicago.edu/story/uchicago-scientists-reveal-jurassic-otter-could-chew-and-swallow-modern-mammals?ref=gottabekidding.me)

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**Hot Take:** Mammal throats have been in development for 165 million years. Water still sometimes goes down the wrong pipe.