【英语时差8,16】食肉鲸和食素鲸（下）（在线收听）

Fossil discoveries have begun to unravel the riddle of whale evolution, providing paleontologists with clues. Indohyus was a fox sized, even toed ungulate found in India. This herbivore was adapted to living in the water like whales, with a bony wall around its middle ear for hearing underwater. When scientists added Indohyus to the collection of more than eighty living and fossil groups and analyzed their genetic relationships and potential evolutionary histories, they found Indohyus like fossils were more likely ancestors for modern whales than mesonychids. Riddle Solved? Not yet. Indohyus could explain the whale’s relationship with hippos, but not the change from herbivore to carnivore, the next step of whale evolution. Of course, like with any good mystery, only new fossil discoveries and time will tell.