Because their bad press precedes them, sharks don’t top many “Favorite Animals” lists. In the ocean, they enforce the evolutionary reality that only the fittest survive. By feeding on the weakest fish, sharks keep fish populations healthy and strong.

Sharks have been around for more than 300 million years without changing very much. But now they’re the ones struggling to survive. Each year, 100 million sharks are killed, and they can’t keep up with such staggering losses. Commercial fisheries claim most of the catch, but shark finning also takes a toll. To fill the demand for shark’s fin soup, sharks are caught and their fins are cut off; then they’re thrown back into the ocean to perish slowly and painfully.

If sharks become extinct, you can bet the ocean’s food chain will suffer. And would that make humans the fittest, or just the greediest?