Q:   If all the ancestors of the whales where "toothed", what gave rise to the baleen whales?
— H. Brown, age 12
A:   Our best idea is that an animal something like Dorudon, a toothed archaeocete (ancient whale) gave rise to all modern whales, both odontocetes (toothed whales) and mysticetes (baleen whales). The early mysticetes actually had teeth that looked a lot like archaeocete teeth, and we think that they used these teeth to strain food from the water. Eventually, their gums elaborated into something that could filter food, eventually becoming baleen. The teeth of mysticetes became small and eventually disappeared.

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Q:   I completely enjoy all of the programs about long-gone animals, but how is it that you can tell me their mating habits, and other things that they do, when we have such questions about living animals, like the great white shark? I'm not criticizing, just wondering.
— Gonza
A:   The mating habits of extinct animals are difficult to determine. Mating sequence of Basilosaurus that was shown on Walking with Prehistoric Beasts was based on a little bit of fossil evidence, the mating behaviors of modern whales, and considerable speculation. The little fossil evidence is what I described on the program. Basilosaurus has tiny hind legs. Dr. Philip Gingerich, who described the legs, thinks the legs were not vestigial (left over structures from their ancestors, but not used) because the joint surfaces on the bones at the knee show that the could be held in two positions, either tucked up against the body, or extended outward. The only reason he could think they would ever extend their legs out might be to help guide the animals during mating. So based on that and the way modern whales mate, the sequence was reconstructed as you saw. It's a good idea, but we really don't know for sure.

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Q:   I wish to become a paleontologist when I grow up and wonder if there are certain steps that need to be fulfilled in order to get into the field. Would there be anything that I would need to be aware of while in college or high school?
— J. Taylor
A:   What I always tell kids who want to be paleontologists is to study everything you can, particularly math and science classes. Math and science will be of obvious help, even if they don't seem to be directly related to paleontology. We use a lot of chemistry and physics in addition to our knowledge of biology and geology. Other classes like computer science and English are important since we need to be able to use computers to perform analysis of all sorts and to communicate effectively with other scientists and the general public.

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