If you've ever watched a dolphin eat, you've noticed that they seem to gulp down their food. That's because dolphins can't chew. Instead, their teeth are used to grip prey. Sometimes, they'll shake it or rub it on the ocean floor to tear it into more manageable pieces. One theory for why they've evolved to do away with chewing is because they need to quickly consume fish before it can swim away. Skipping the process of chewing ensures their meal doesn't escape.