Odds of Getting In
The odds are pretty decent for such scientists as biochemists or biophysicists, but not so good for others, such as marine biologists. The good news is that the branches of science that are easiest to make money at are the ones that are the most in demand.
In other words, keep your love of whales to yourself—suck it up and become a stem cell biologist. You can move to the coast and go whale-watching on your day off.