SCIENCE* LAB SCHOOLS : PREHISTORIC BLUBBER

Some two million years ago, a large mammal swimming through the North Atlantic Ocean hauled its bulk up onto a beach, its belly full of clams. It had blubber, tusks and more than likely, whiskers.

Sounds like a walrus, right? In fact, the extinct animal was a member of a different marine mammal genus, as different from a modern walrus as a fox is from your dog.

But for all the evolutionary differences between the animals, researchers say in a study published in the journal PeerJ Life & Environment, this relative of the walrus may have used a very similar foraging strategy : suction feeding.

Mathieu Boisville, a paleontologist at the University of Tsukuba in Japan and an author of the study, said that '' it's really something quite rare in the field of fossil marine mammals '' for two large animals to develop such similar adaptations.

The phenomenon is known as convergent evolution.

The false walrus, which Dr. Boisville and his colleagues named Ontocetus posti, belongs to a group of marine mammals that first appeared around five million years ago on the Pacific Coast of North America, then spread into the Atlantic Ocean via a not-yet closed seaway between North and South America.

Most remains from the animal in the group are found around the southeastern shores of the United States.

But over several decades, amateurs and paleontologists have found scraps of skull and lower jaw along the coasts and seabed of the North Sea. Dr. Bolsville said, not far from Antwerp in Belgium and Norwich in England. [ Asher Elbein ]