Environment

All in the Whale Family

By Josie GlausiuszDec 1, 2001 6:00 AM
rd_whale1.jpg
Ancient proto-whale skull: 60 cm/23.4 in. Photograph courtesy of University of Michigan/Michigan Museum of Paleontology | NULL

Newsletter

Sign up for our email newsletter for the latest science news
 

Heavy of head and clumsy of tread, the hippopotamus seems an unlikely evolutionary sister to whales and dolphins. Yet two ancient anklebones from Pakistan indicate that whales are descended from artiodactyls, a group of even-toed hoofed mammals that includes modern sheep, cows, pigs, and camels—along with hippos, which appear to be whales' closest living relatives.

Working with colleagues at the Geological Survey of Pakistan in Quetta, paleontologist Philip Gingerich of the University of Michigan unearthed the skeletons of 47-million-year-old proto-whales at a dig in Pakistan's Baluchistan province. The strange-looking beasts, which were about the size of modern-day sea lions, appeared to have the head of an ancient whale and the anklebones of an artiodactyl. With a long snout and webbed, flipperlike hind feet, the extinct species was probably well adapted to swimming in shallow seas but also able to crawl onto land with its hoofed forelimbs. It is the anklebones, however, that most excited Gingerich. Grooves in the bones indicate that the animals could flex their feet in two places, just as modern artiodactyls do.

Proto-whale anklebone: 15 cm/5.85 in. Photograph courtesy of University of Michigan/Michigan Museum of Paleontology | NULL

DNA studies had hinted at the hippo-whale connection, but previous fossil finds appeared to contradict it. The newfound remains confirm the connection: The animals' feet and hands closely resemble those of anthracotheres, ancient land-dwelling artiodactyls that were ancestral to hippopotamuses. "This is a Rosetta stone linking whales to the artiodactyls on land," says Gingerich. "To decipher the Rosetta stone, it was necessary to get both languages on the same stone, to prove that they represent the same text. And that's what these discoveries are."

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!

Subscribe

Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Join
Our List

Sign up for our weekly science updates.

 
Subscribe
To The Magazine

Save up to 70% off the cover price when you subscribe to Discover magazine.

Copyright © 2022 Kalmbach Media Co.