How Many Stomachs Does a Dolphin Have?

Dolphins have only one stomach, but it is compartmentalized into three sections. These compartments allow a dolphin to consume a great deal of food quickly and digest it later, in case they are eating somewhere they might encounter predators of their own.

Function

A dolphin's stomach has different chambers, similar to grass-eating animals such as cows, llamas and deer, although the purpose is different. The terrestrial animals need extra compartments to break down the cellulose of the plants they eat, while dolphins need compartments to store food in their bodies and digest it later.

Types

The first stomach is called the forestomach. It is basically an enlargement of the esophagus, is muscular and can extend significantly. The forestomach can store food for later digestion. Although many species of dolphins have teeth, they usually swallow fish whole, and the mastication process begins in the forestomach. This is similar to the way a bird grinds food in its gizzard rather than in its mouth.
Dolphins also have been observed expelling large amounts of water through their mouths, and researchers speculate this water may be coming from the forestomach. A dolphin might intake this water when catching prey, swallow the water into its forestomach, and then once it secures the prey against the palate, the dolphin then shoots the water out of the forestomach and out of its mouth.

Features

The majority of digestion occurs in the second chamber, the glandular compartment. This chamber contains enzymes and hydrochloric acid, similar to those in single stomachs of mammals, which break food down for nutrition that can be absorbed by the dolphin's body.

Effects

The third chamber is the pyloric stomach, a U-shaped compartment which finishes the digestive process before the contents empty into the intestines. The pyloric stomach ends in a sphincter muscle which regulates flow of digested food into the duodenum of the small intestine. An expanded sac at the beginning of the duodenum is sometimes mistaken for a fourth stomach.

Identification

Dolphins are cetaceans, the mammalian order which includes porpoises and whales. There are 32 oceanic species of dolphins, all of which are carnivores and eat fish. Different species also eat squid and octopus, and crustaceans such as lobsters, shrimp and crabs.
The most commonly-recognized dolphin species, the bottlenose, weighs anywhere from 440 to 600 lbs. This dolphin can eat up to 30 lbs. of fish a day--and nursing mothers eat even more.

Resources

• Fun facts about dolphins