Bottlenose Dolphins

Universally loved, dolphins are our best known animals. Bottlenose dolphins inhabit both temperate and tropical waters and are usually found in pods, or schools. In North America, the bottlenose dolphin is found along both coasts of the United States. In the Atlantic, it is the most common dolphin species along the eastern coast from Cape Cod through the Gulf of Mexico.

The robust body with a short stubby rostrum (beak), earning it the name “bottlenose”. The Atlantic Bottlenose dolphin (Tursiops truncatus) grows to be 7-10 feet long and weighs between 300-500 pounds. The calf is usually 28 to 36 inches long and weighs 25 to 40 pounds at birth, after a gestation of 11 to 12 months.

Differences in Bottlenose Dolphins

There are two forms of the bottlenose dolphin, of which the coastal or inshore form generally frequents harbors, bays, lagoons and estuaries. The potential life span is as long as 35-50 years, with female dolphins tending to live longer than male. Age is determined by examining a sliced section of a tooth and counting the growth layers, much like you would count the growth rings in a tree.

Behavior

Dolphins establish dominance with threatening postures and gestures such as smacking their tails on the water, jaw snapping, raking and physical fighting. They are fascinating creatures to watch, because of their tendency to jump out of the water and land on their backs or sides in a behavior called breach. They also communicate through clicks and sounds similar to moans or whistles, which intrigues observers.

Coonservation Status

While bottlenose dolphins are not endangered, some populations are depleted. In U.S. waters, they are protected by the U.S. Marine Mammal Protection Act.

Bottlenose dolphins are a top predator in the ocean, with few predators of their own. Sharks and killer whales occasionally prey upon them but the major threat comes from humans, when they are caught in fishing gear.