A. Food preferences and resources..

Dolphins are active predators and eat a wide variety of fishes, squids, and crustaceans such as shrimps. The foods available to a dolphin vary with its geographic location (Barros and Odell, 1990).

B. Food intake.

1 . Adult bottlenose dolphins eat approximately 4% to 5% of their body weight in food per day. A nursing mother's daily intake is considerably higher: about 8% (Cockcroft and Ross, 1990).

2. A dolphin's stomach is compartmentalized for rapid digestion. It can also function as a crop when food is taken opportunistically.

C. Methods of collecting food.

1 . Feeding behavior is flexible and adapted to a dolphin's particular habitat and available food resources.

2. Dolphins do not chew their food. Usually they swallow fish whole, head first, so the spines of the fish won't catch in their throats. They break larger fish by shaking them or rubbing them on the ocean floor.

3. Hunting strategies are varied and diverse.

a. Bottlenose dolphins often cooperate when hunting and catching fish.

(1) In open waters, a dolphin pod sometimes encircles a large school of fish and herds them into a small, dense mass, sometimes using their tail flukes to stun the fish. The dolphins take turns charging through the school to feed.

(2) Occasionally dolphins herd schools of fish against a sand bar or shoreline to trap them in shallow water where they are easy prey (Shane, et al., 1986).

b. Dolphins also feed on individual, nonschooling fishes (Shane, 1990).

c. To hunt larger fishes, a bottlenose dolphin may use its tail flukes to kick a fish out of the water, then retrieve the stunned prey (Shane, 1990).

d. Bottlenose dolphins often feed in association with fishing operations. Dolphins in Texas bays frequently accompany shrimp boats. They feed on fishes that are caught incidentally in trawl nets intended for shrimps (Fertl and Wursig, 1993).

A pod of dolphins sometimes encircles a school of fish and herds them into a tight ball for feeding.