Dolphins come in 33 types including marine, river, and killer whales. They have smooth skin, a dorsal fin, flippers, and a fluke tail. Color varies by type from gray to white to black. Dolphins are social, intelligent animals that hunt in groups but eat individually. They eat fish, squid, and shrimp totaling 4-5% of their body weight daily. Dolphins communicate well with humans and may protect people from sharks.