Dolphins are creatures which are constantly on the move and lead very active lifestyles. This means that they need to be able to take in a huge number of calories to ensure their continued survival. This has a huge impact on what they eat, as some foods are much more efficient at giving them the nutrients they need.
The exact types of food eaten by dolphins depends entirely on each individual species. The smaller dolphins can only manage to catch and eat smaller prey, whereas the size and speed of the larger species of dolphins enables them to be more ambitious in what they choose to catch and eat.
Some dolphins also use their tails to hunt. They can hit their prey with substantial force which will stun it temporarily. The dolphin can then seize this opportunity to eat it whilst the prey is disorientated. All dolphins make the most of their speed and their bodies’ manipulation of the flow of water to ‘herd’ large numbers of fish. They almost always hunt in groups as it makes the job much easier. The dolphins will alternate the roles of the hunting pack, so that every dolphin at some point gets the chance to swallow what they can whilst being protected by the others around them.
All dolphins eat water-dwelling creatures native to their habitat. The general assumption is that dolphins eat fish, but their diet is actually far more varied than this. Bottlenose dolphins have a diet which primarily comprises small fish, but they also regularly eat squid, some species of crab and a lot of shrimp. River dolphins eat freshwater fish native to their surrounding habitat, which often includes gobies, trout and carp. Smaller dolphins eat crustaceans when they cannot find enough fish to go around and Spinner dolphins have even been known to eat jellyfish.
Perhaps the most surprising diet of any dolphin is that of the killer whale. As well as eating larger fish, the killer whale hunts in groups to attack and kill large sea mammals. They eat sea turtles, sea lions and seals on a regular basis, sharing the effort of hunting and the reward of the kill between members of the group. Killer whales have even been found with dolphin remains in their stomachs, but it is widely accepted that dolphins do not form a key part of their diet and they only eat them in exceptional circumstances.