Some friends went on a cruise to Alaska and were excited to tell me about all the ocean wildlife they saw and all the interesting facts they learned. In particular, they were very eager to discuss whale evolution. My friend exclaimed, “We learned from the naturalist on board that whales descended from kangaroos!” My reaction, “You learned what?!” Thinking…maybe I misheard. But to my surprise he repeated the bit about kangaroos.
It was my job to break the news, “Whales did not descend from kangaroos.” It took some convincing…my friend had been quite impressed with the cruise naturalist and had really bought into the whole kangaroo story. Also, it didn’t help that I couldn’t remember the name of the whale’s ancestor. I explained, “They descended from an a animal that looked like a wolf, a four-legged mammal.”
Later I went home and pulled out my whale watch naturalist training manual and flipped to the page on cetacean evolution (Cetacea is the scientific order for whales, dolphins and porpoises). And there was the answer…mesonychid, the ancestor of whales that kind of looks like a wolf, but is not related to wolves. But is that still the answer?
As new fossils are discovered and new studies are done, the story of whale evolution keeps evolving (ha, see what I did there). Now some scientists think that whales directly descended from artiodactyls, a group of hoofed animals that split from the mesonychids and evolved separately. Overall, the Wikipedia article on the evolution of cetaceans provides a good explanation of this newer theory and the DNA analysis that led to the conclusion. But the bottom-line is that there is no mention of kangaroos!
So the next time you’re talking to a naturalist and some really wild fact pops up, make sure you ask questions. Where did you learn that? Where did you train to be a naturalist? Do you know where I can find more information on this topic? If something doesn’t sound right, always do your own fact checking.