Darwin's bear supposition was just that. He was wrong about a number of things. The ancestor of whales was not a carnivore it was an even-toed ungulate. Darwin was right about a several important things. First, whales did come from some form of land mammal. Second, somehow these ancestors gained an advantage from moving out into the water. Finally, this process took a very long time. All three of these deductions of Darwin have been proven correct. Laugh if you want to, but Darwin understood whale evolution alot better than you do. He did not have the advantage of the science of the last few decades that you choose to ridicule and ignore.