Table of Contents
History with Kayleigh presents Wadi Al Hitan, southwest of Cairo, as the clearest place to watch whales return to the sea. About 37 million years ago a warm Tethys sea covered western Egypt. Bodies sank, sediment sealed them, the sea left, and wind uncovered the bones. Geologists in 1902 found hundreds of skeletons, some with feet. Darwin, she notes, had treated that return to water as a hard case for natural selection. Philip Gingerich of the University of Michigan, digging from the 1980s, exposed hind legs and knees on a Basilosaurus in 1989. The limbs were complete and useless for walking. The fossils are mostly that long eel shaped form and a stockier Dorudon with serrated teeth. A genetic result repeated here names the hippopotamus as the nearest living relative. The talk runs from shoreline mammals near 55 million years ago to animals that never came ashore, then to a cooling near 34 million years ago that brought blubber and echolocation. The valley has been a World Heritage site since 2005, at risk from theft and erosion.
Key points
- Wadi Al Hitan preserves whales from a Tethys sea that covered western Egypt about 37 million years ago.
- Feet and knees on Basilosaurus, uncovered by Philip Gingerich in 1989, are presented as the missing transition.
- Dorudon and Basilosaurus are the two main extinct forms, one a birth nursery and the other a predator.
- The talk repeats a genetic claim that hippos are the closest living relatives of whales.
- The longer story runs from shoreline mammals near 55 million years ago to fully marine whales after the Eocene cooling.
- The UNESCO site is described as well kept but exposed to theft, visitors, and wind.
Short quotes
Charles Darwin recognized the conundrum as one of the great challenges to his theory of evolution by natural selection
Kayleigh, Wadi Al Hitan and whale evolution
She uses Darwin’s own difficulty to explain why the desert feet matter. Watch at 4:19
University of Michigan's paleontologist Philip [Gingerich] began Excavating Wadi al-hitan in the 1980s
Kayleigh, Wadi Al Hitan and whale evolution
The Michigan dig is the expedition she credits with the hind limb finds. Watch at 6:46
Video by History with Kayleigh. Watch on YouTube.