About 43 million years ago, when South America was surrounded by water on all sides, there lived a whale with four legs, elongated toes, sharp teeth and perhaps even fur.
This ancient creature looked more like the love child of an otter and a crocodile than any modern-day whale. And, unlike today’s whales, which dwell exclusively in the sea, this animal lived some of its life on land.
“I think they were not very good at walking, and certainly not at running,” said Olivier Lambert, a vertebrate paleontologist at the Royal Belgian Institute of Natural Sciences in Brussels.
Lambert has spent a lot of time with this whale, which was discovered in 2011 less than a mile from the beach along the southern coast of Peru.
It didn’t take long for the researchers excavating the site to recognize some of the specimen’s remarkable features. Among them:
• It had four limbs, like the whales that first evolved in present-day Pakistan and India more than 50 million years ago.
• It was one of the earliest whales known to have lived in the New World.
• It belonged to an entirely new genus and species of whales.
“We found a really incredible specimen,” said paleontologist Rodolfo Salas-Gismondi of Cayetano Heredia University in Lima, who was part of the team that reported the find Thursday in the journal Current Biology.
The study authors dubbed it Peregocetus pacificus, or “the traveling whale that reached the Pacific.” The name honors its role in helping scientists understand how early whales migrated from the Mediterranean to the Atlantic and eventually to the New World, said Lambert, the study’s lead author.
The specimen’s fossilized remains are not only very old and very much intact.
“It was almost a complete specimen,” Salas-Gismondi said. “It was something we never expected to collect.”
The connections between the bones indicated that this whale had reached adulthood. It probably measured about 13 feet from tip to tail, and it weighed at least several hundred pounds.
Peregocetus had a long snout and a mouth with teeth sharp enough for it to hunt large animals and cut its prey into smaller pieces. (The pointed regions on its pre-molars and molars helped the study team classify the specimen as a four-legged whale.)
Its legs were strong enough for the creature to stand on land, and it had hooves at the ends of its fingers and toes.
But Peregocetus also likely had webbed feet to help it swim, Lambert said. Just like an otter, it might start by pushing back on its hind limbs. Then it might shift to undulating its body up and down from the tail to the hip.
