When it comes to survival one of the most crucial parts of life for marine mammals such as dolphins is there ability to locate and obtain abundant sources of high quality foods.
Without abundant quantities of fish and other types of prey dolphins would have a hard time thriving in the ocean and inhibiting certain types of environments where particular food sources are likely to live.
The consumption of marine mammals however is restricted to certain locations and limited to only 2 or so known dolphin species.
Most species of dolphin will hunt for and consume fish such as cod, herring and mackerel, however in areas such as the amazon dolphins may also consume piranha and other local fish.
Common foods dolphins consume:
- Sea turtles
- Marine mammal (rare and species restricted)
While most species of dolphin are known to consume small fish, crustaceans and other forms of small prey larger dolphins such as the killer whale and false killer whale may hunt other marine mammals, large animals and marine birds when smaller prey such as fish, squid and crustaceans may not be an available choice or a sufficient food source for their needs.
Killer whales in particular are know to focus on specific diets based on where they live and the pod they belong to.
Areas that supply large quantities of marine mammals such as Alaska make excellent hunting grounds for killer wales that thrive off of marine mammal meat while various locations in the North Pacific offer large quantities of fish and squid for non marine mammal eating killer whales.
Among those that are known to consume marine mammals as part of the diet the types of marine mammals these dolphins hunt may include sea lions, walruses, seals, sharks, penguins, seabirds and large whales.
Common foods for dolphins that consume marine mammals:
- Sea lions
As you can see the variety of foods dolphins consume can vary significantly based on their species, location and availability of various food sources.
Note: Both the killer whale and false killer whale belong to the dolphin family despite the world “whale” being a part of their name.
How dolphins hunt for food
Because of the strong social structure dolphins have many species hunt for food in groups or pods and work collaboratively to capture their prey.
One technique dolphins frequently use to hunt for food is called bait balling.
The bait ball technique is used to capture schools of fish and requires a pod of dolphins to swim around in a circle around the school of fish, which forces the fish to herd themselves into a tightly knit ball allowing them to become easy prey.
Bait balling makes eat easier for dolphins to create abundant source of food in a small area by preventing the fish from being able to escape in any direction.
Once the fish are pinned down into a tight ball the dolphins can rush in and pick the fish off one at a time.
Another technique that is commonly used by dolphins in or near shallow waters is known as corralling.
This works by chasing the fish into shallow waters or getting them into a small narrow place where they can be pinned against a wall or mud bank so they are unable to escape.
Similar to a bait ball the school of fish will be limited in mobility and most will be unable to escape while the dolphins move in and attack them.
Some dolphins may also use their tail to hit and stun the fish in order to paralyze them long enough to be defenseless while the dolphins attack them.
While it is difficult to determine exactly how much food a dolphin consumes it is safe to say that depending on the dolphins species most dolphins can consume anywhere between 2% – 10% of their total body weight in food each day.
In addition to communicating with one another when hunting for food in groups dolphins are also able to hunt for food using echolocation which allows them to create sound waves in order to detect fish and other objects in the area by bouncing the sound waves off of the objects and interpreting the information that is returned to them through the echo’s they emit.
Information can include the size, distance, direction, speed and thickness of an object in order to provide the dolphin with vital data that will allow it to determine what the object is.
Echolocation is extremely important in areas that lack light as the dolphins must rely on their sense of sound to search for food, navigate the ocean and maintain awareness of potential predators.