Bottlenose Dolphin - Tursiops truncatus

Bottlenose Dolphin
Tursiops truncatus

Other Names: Gray Porpoise, Black Porpoise, Bottle-nosed Dolphin, Atlantic (or Pacific) Bottlenose Dolphin, Cowfish

Habitat: Inshore and offshore

Status: Common

Population: Unknown

Threats: Hunting/whaling, entanglement in fishing lines, pollution, human disturbances, and habitat destruction

Group Size: 1-10 (inshore); 1-25 (offshore), up to 500 may occur offshore

Fin Position: Center

Newborns: 34" - 4˝' (85cm - 1.3m), 35-65lb (15-30 kg)

Adults: 6Ľ' - 12' (1.9 - 3.9m), 330 - 1,435lb (150 - 650kg)

Diet: Fish, squid or octopus, and occasionally krill or other crustaceans

Teeth: 40 - 52 on the top row, 36 - 48 on the bottom row

Description

Dorsal fin:

- center of dorsal fin may be paler than margins
- slightly hooked tip
- prominent, falcate dorsal fin (variable)
- broad base

Flukes:

- concave trailing edges
- distinct notch in middle

Flippers:

- moderately long, dark, slender flippers
- pointed tips
-broad base

Other characteristics:

- sharp crease between beak and forehead
- rounded forehead (variable)
- dark bluish gray or brownish gray cape (usually indistinct at a distance)
- may be extensive scarring on some adults
- thick tail stock
- paler gray or brownish gray sides
- off-white, light gray, or pinkish underside (may be some spotting in older animals
- robust body and head
- dark stripe from eye to flipper
- fairly short beak (length and thickness variable)

Behavior

- often lifts flukes above surface on a dive
- highly active at surface
- frequently lobtails, bow-rides, wake-rides, body-surfs, rides pressure waves of large whales, and breaches (sometimes leaping several meters high)
- may be found in association with a variety of other cetaceans, as well as sharks and sea turtles
- wild, lone individuals (usually males) sometimes seek out swimmers and small boats, remaining in the same area for years
- powerful swimmers
- dives rarely last longer than 3 to 4 minutes inshore, but sometimes longer offshore
- typically shows forehead when surfacing, but rarely the beak
- in some areas, will chase fish out of the water, beaching itself before wiggling back
- groups may provide usual assistance to one another
- sometimes cooperate with local fishers

Distribution

- widely distributed in cold temperate to tropical seas worldwide
- found in many enclosed seas such as the Black, Red, and Mediterranean Seas and the Gulf of California (Sea or Cortez), Mexico
- some offshore populations seem to undertake seasonal migrations
- many inshore populations are resident year-round
- outside tropical waters, seen mainly inshore in a wide range of coastal habitats from open coasts with strong surf to lagoons, large estuaries, and even the lower reaches of rivers and harbors
- offshore form common around oceanic islands, but can be seen in the open sea in the eastern tropical Pacific and elsewhere
- in the northern North Atlantic, rare further north than the United Kingdom

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu

Internet Coordinator: Candice Orca Mottet

e-mail questions, comments, and/or suggestions to wcrc@sci.tamucc.edu

e-mail questions, comments, and/or suggestions to
wcrc@sci.tamucc.edu