Atlas Obscura has a post and podcast about the Valley of the Whales. The Valley of the Whales is a place in Egypt that is just overflowing with whale bones. Its discovery in 1902 provided valuable information about the evolution of the whales.
Few sites in the world speak of an evolutionary tale as rich and captivating as that of Wadi al-Hitan, Egypt’s “Whale Valley.” There, amid a wind-sculpted landscape of sand and rocks, lies a large collection of the most unexpected of animal remains—whale fossils.
To be exact, the scattered bones belong to a long-extinct suborder of whales known as archaeoceti. What really sets these ancient creatures apart from your ordinary, modern-day cetacean is one odd, yet profoundly important, anatomical difference—hind legs. This critical deviation in the fossil record of whales is the basis for the notion that the massive seafaring beasts we know today began their existence as land-based animals.
But since their discovery in 1902, the fossils of Wadi al-Hitan have tended to raise more questions than they’ve answered. While the hundreds of archaeocete skeletons provide a rare and valuable snapshot of whales in the final stages of losing their hind limbs and transitioning to a marine existence, evolutionary biologists are still left puzzled over the identity of the whale’s earliest ancestor.
Similarities in tooth-shape led to the long-held belief that whales were related to mesonychids, carnivorous hoofed mammals that closely resembled wolves. It wasn’t until 2005 that a team of American and French scientists finally discovered the missing link between whales and their closest relative, the hippopotamus. This discovery, supported by another collection of cetacean fossils located in Pakistan, placed the whale in the different taxonomic group of artiodactyls, which includes such unexpected relatives as camels, pigs, and giraffes.