Dolphins are very intelligent animals, and they are social ones too. Bottlenose dolphins form nursery groups of mothers and calves, groups of young dolphins, and bonded pairs of adult males. A bottlenose dolphin group often breaks apart and re-forms with different members. Each bottlenose dolphin develops its own signature whistle. A calf starts to develop its signature whistle in its first months of life. Scientists think a signature whistle works like a name.

Dolphin calves learn how to hunt mostly by watching their mothers. Dolphins work together to herd fish into a group before they feed. Some bottlenose dolphins hit fish with their tails, which is called fish-whacking. Some strand-feed: they rush onto mud banks or the shore to catch fish stranded there. Some dolphins in Shark Bay, Australia, wear sea sponges on their snouts while they search the sea floor for food.

A bottlenose dolphin can be 12 feet long and weigh more than 1,000 pounds. A newborn calf is about 2.7 to 4.6 feet long. The orca, or killer whale, is the largest member of the dolphin family. It can reach about 31 feet long. Dolphins and porpoises are both toothed whales, but dolphins tend to have cone-shaped teeth and porpoises have spade-shaped teeth.

Dolphins find things by making sounds that bounce off objects and return as echoes. This is called echolocation. A waxy, lens-shaped part in the forehead, called the melon, focuses the clicks into a beam. The echoes come back through the lower jaw. Some dolphins also find fish by listening for the sounds the fish make. Besides clicks, dolphins make whistles.

Some bottlenose dolphins live for more than 50 years. Scientists tell individual dolphins apart by the nicks and notches on their dorsal fins. Large sharks are the main natural predators of bottlenose dolphins. Dolphins often swim near the front of ships and ride the waves the boats make. A bottlenose dolphin calf usually stays with its mother for 3 to 6 years.

As of November 2026, the IUCN Red List lists the common bottlenose dolphin as Least Concern. As of November 2026, getting tangled in fishing gear is one of the main threats to bottlenose dolphins. In the United States, they are protected by the Marine Mammal Protection Act of 1972. Feeding wild dolphins is harmful, because it teaches them to come close to boats and people. As of November 2026, people should stay at least 50 yards (46 meters) away from wild dolphins.

Words to know

• signature: one's own
• nursery: calf-care group
• echolocation: finding by echoes
• melon: forehead lump
• predators: hunting animals