What is a snakehead fish? What is an alligator turtle? What is a maned wolf? What is a loggerhead turtle? What is a Komodo dragon? What is a pteranodon? What is an alligator gar? What are some extinct amphibians? What is a tarsier? What is a skink's habitat? What kind of animal ...
One way to answer that question would be to look at evolution's record on the topic. Every timeevolutionhas put a mammal in the water, whether it's a whale, a porpoise, a walrus or a manatee, evolution always does it with lungs rather than gills. Evolution often does drastic things to...