We know that aquatic mammals (whales, dolphins, manatees, etc) evolved from land animals who returned to the ocean. Here's a new example of what the in-between version may have looked like. The fossil remains of a 42-million-year-old quadruped whale have been found in Peru. The find is significant because scientists say early whales swam from Africa to South America, and this one shows they made it to the Pacific, too. The new species, Peregocetus pacificus, appears to have been equally adept at walking and swimming.
Analysis of the Peregocetus fossil shows it was well adapted to both land and sea, bearing characteristics similar to modern otters and beavers. This animal was relatively large, measuring around 4 meters (13 feet) in length, which is more than twice the size of otters living today. Peregocetus’s terrestrial abilities were evidenced by small hooves at the tips of its fingers and the orientation of its hip bones, suggesting a quadrupedal gait on land. At the same time, it had tail bones similar to those of beavers and otters, which means its tail played an important role in its aquatic abilities. Finally, the size of its fingers and feet suggests webbed appendages, according to the researchers.
Read more about Peregocetus pacificus and what it tells us at Gizmodo.
(Image credit: Alberto Gennari)