I’ve always figured whales had legs, dividing them between land and sea. And last year, findings from a new in-depth study — published in the Journal of Vertebrate Paleontology — helped me fill in that evolutionary gap between the enormous sea mammals of today and their (possibly) amphibious ancestors.
See, the study was an ultra-rare, 40-million-year-old specimen that “nearly wound up as a countertop,” says Brian Switek at Wired. An Italian marble cutter found a strange animal’s skull nested in finely cut slabs of rock. The man thought he had discovered a dinosaur. But he was wrong. Researchers traced the stone’s origin to a limestone quarry in Egypt’s Tarfa Valley, and pieced the fossil back together there. Though its bones “had been hacked into six pieces… because the cuts were so smooth,” the skeleton was easily reconstructed, says Ed Yong at Discover. They dubbed the animal aegyptocetus tarfa, which translates to “Egyptian whale from Tarfa.”
The ancient whale belonged to a group of mammals related to modern toothed whales and dolphins. Its skull was more than two feet long, and the creature itself likely weighed more than 1,400 pounds. It had a specially adapted skull that allowed it to hear echoes underwater, and a nose structure that suggests it was able to smell — critical for tracking prey on land. Smell is a sense that most modern whales lack. Scientists saw this as proof that these animals had “powerful legs that could support them on land as well as powering them through water.” Though strangely, the legs were nowhere to be found.
So where did these legs go? They were probably eaten. “Toothmarks on its ribcage indicate it might have been attacked from its right flank,” says Jennifer Welsh at Live Science — similar to how modern sharks ambush their prey. Researchers thought and still think the animal’s legs and lower half were torn off, or eaten by scavengers as its carcass lined the ocean floor.
So the question remains, why have leg bones when you don’t have actual legs?
The scientific answer is evolutionary adaptation.Whales are mammals that evolved from land based mammals to live in water and in doing so gradually adapted to a more streamlined body suitable for swimming rather than walking. But the leg bones of the ancestors didn’t fall off or go away, they were just absorbed into the soft tissue of the body. But they are still there. Your Thoughts?
Note: This is just scratching the surface of this question, so if anyone has anything to add or dispute please do!