Dolphins are a widely distributed and diverse group of aquatic mammals. They are an informal grouping within the order Cetacea, excluding whales and porpoises, so to zoologists the grouping is paraphyletic. read more
Sharks actually attack dolphins on occasion, but sharks are wary of them because dolphins have excellent detection skills in the water, are highly intelligent, attack in groups and occasionally protect other mammals including humans even if they aren’t part of the dolphin’s pod. read more
Great question! It does seem sort of crazy that sharks would be scared of dolphins. But there is actually a good reason. Sharks like to eat animals that are smaller than them - they particularly like to eat young (baby) dolphins. Dolphins, however, are really smart animals, so they've long since figured this out. read more