Common Bottlenose Dolphin

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Common Bottlenose Dolphin

Tursiops truncatus

Range/Geographical Distribution: Bottlenose dolphins can be found in all oceans and seas at tropical and temperate latitudes.

Habitat: Coastal populations reside along the continents and most oceanic islands, including bays and estuaries.  Pelagic populations live offshore in places like the Gulf Stream of the North Atlantic.

Description: Although there is considerable variation in this species, common bottlenose dolphins tend to have a wide head and body, a short beak (snout), long flippers, and a tall dorsal fin.  The body color consists of shades of gray with strong counter shading (darker above and lighter below).  The flippers, fluke, and dorsal fin are a dark gray.  Rake marks, caused from other dolphins’ teeth, are often seen on the body.  Pelagic animals tend to be larger than coastal ones.

Size: Adults range from eight to 12 feet long and can weigh over 1,000 lbs.  At birth, calves weigh 30-45 lbs. and are 33-55” long.

Food: Coastal populations eat fish and invertebrates near the ocean floor.  Pelagic populations eat pelagic fish and squid and have been known to dive over 1,600 feet.  Bottlenose dolphins are often attracted to fishing boats and have learned to feed near shrimp trawlers.

Breeding: After a one-year gestation, mothers give birth to calves and then nurse the calf for up to 20 months after birth.  Females only give birth every three years and calves may be born during any season, although winter births are less common.

Predators: Sharks and killer whales.

Conservation Status: Worldwide, the common bottlenose dolphin is abundant but some local populations are at risk from habitat degradation, fishery conflicts, viral outbreaks, pollutions, and hunting.  Dolphins were killed in fisheries in the United States until the 1920s, in the Black Sea until the 1990s, and are still hunted in Japan.

Interesting Facts: Groups of related female dolphins may stay together for many years and pair bonds between males are known to last at least 20 years.  Bottlenose dolphins often “bow ride” on ships and surf in all kinds of waves. 

On the Coast: Coastal Georgia bottlenose dolphins can be seen along the beach or within the rivers and estuaries.  Georgia’s uniquely large tidal range allows dolphins to forage by strand feeding – herding fish up onto the mud flats along estuaries where the dolphins then pick up the fish off of the mud.  Local dolphins also display “begging” behaviors and approach boats for handouts.  This unnatural behavior can have many negative effects on individual dolphins including malnourishment, boat collisions, and loss of natural foraging behaviors.  Under the Marine Mammal Protection Act it is illegal to harass or feed dolphins and doing so can result in fines up to $100,000 and a one-year imprisonment.

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