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Species Description

Bottlenose Dolphin

Tursiops truncatus


Classification

Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Cetacea
Family: Delphinidae

Description

Color: Light to purplish gray on upper parts of body. Sides pale gray, belly white. Adults range in size from 2.4 - 3.7 m (8 - 12 ft) in total length. Bottlenose Dolphins are probably the most familiar of all cetaceans to the general public, since most people have seen them on television programs and commercials, or at aquariums, zoos, and marine parks.

Life Cycle

Breeding activity peaks in March and April, and the gestation period is about 12 months. The single calf is born between the months of February and May. Its average weight at birth is 13.6 kg (30 lb.) and it is approximately 1.1 m (3.5 ft) in length. The calf is born tail first and swims immediately to the surface to breath. It will suckle for 18 months before it is weaned. A female Bottlenose Dolphin reaches sexual maturity at 6 years of age and then produces young every 2- 3 years. A male reaches sexual maturity by 10 years of age.

Natural History

The preferred habitat for this species is coastal shallow waters such as bays, estuaries, passes, and inlets, but it will also inhabit offshore waters within the 100 fathom (600 ft) depth line. The Bottlenose Dolphin feeds primarily on fish, but will also eat shrimp, crabs, and squid. It has been observed to herd fish into tight schools, which makes it easier to catch prey. It is also attracted to shrimp trawlers, where it feeds on fish attracted to the boat or the bycatch (unwanted fish, etc.) which is dumped over the side. The Bottlenose Dolphins is known for its ability to use echolocation not only to locate objects but also to discriminate between different sizes and shapes. A group or pod of Bottlenose Dolphins has a social hierarchy where males compete for dominance based on larger body size. Females do not engage in this social dominance behavior.

Range

This abundant marine mammal inhabits coastal and in-shore marine waters from Massachusetts southward through the Caribbean and Gulf of Mexico. This species occurs in coastal areas throughout most of the oceans of the world.

Conservation Status

As with all marine mammals, the Bottlenose Dolphin is protected from hunting or wanton killing by international agreement and by state and federal laws. Populations of this species are stable at this time.

Similar Species

Other dolphins are smaller or have different color patterns. new marine mammals/Ttruncatus