When it comes to diet dolphins are known to eat a variety of different foods which can vary greatly depending on the dolphins species, hunting methods, social structure anatomical features (i.e. overall size and teeth).
One of the most determinant factors involved in a dolphins diet is the species it belongs to with smaller species often eating small prey that is easy to swallow and digest while a few of the larger species are able to consume much larger prey.
In terms of diet some of the most popular types of foods dolphins are known to hunt for include fish, cod, herring, mackerel, squid, plankton, krill, cephalopods and crustaceans while larger dolphin species such as the killer whale and false killer whale (the killer whale actually belongs to the dolphin family) can be seen consuming larger prey such as large squid, sea lions, walruses, seals, sharks, seabirds, turtles and even large whales.
As a species dolphins are extremely social creatures and spend will their time together on a number of different activities including hunting for food.
By hunting as a group these marine mammals maximize their ability to successfully capture their prey while avoiding being injured or attacked.
During hunting expeditions dolphins can often be seen traveling together in pods consisting of 2 – 30 dolphins using a number of sophisticated strategies and group oriented hunting techniques to stun, isolate and capture their prey.
One technique dolphins are known to use (known as a bait ball) to capture fish involves a group of dolphins swimming around a pool of fish in a circle, which forces the fish to form into a tightly knit ball.
Once the fish are gathered together and unable to escape the dolphins will then taking turns darting in and picking off the helpless fish off one by one.
Another popular technique dolphins use when hunting for prey is known as corralling.
Corralling is a technique that is commonly used by dolphins that live in or around shallow waters and rivers (coastal dolphins) and requires the dolphins to chase the fish into shallow waters or rivers banks where they can get the fish into a small narrow corner against a mud bank, ship or wall so that the fish become trapped and have no way to escape while the dolphins move in and attack them.
While hunting fish some dolphins will also use their tail to hit and smack the fish which temporarily stuns and paralyzes them long enough to allow the dolphins to attack them as they lay defenseless.
In areas where light is low or completely absent dolphins can rely on echolocation to find their prey.
By using echolocation dolphins can determine where an object is, how far it is, whether it is above or below them, how fast it is moving, what direction its moving in and whether the object is hallow or dense.
This not only helps dolphins locate food, it also helps them navigate the often pitch black ocean.
While there is no exact estimate on how much food a dolphin is likely to consume on a daily basis most dolphins will consume between 4% – 10% of their body-weight in food on a day-to-day basis.