Long-beaked Common Dolphin. Credit: NOAA Fisheries
Long-beaked Common Dolphin. Credit: NOAA Fisheries
About the Species
Long-beaked Common Dolphin. Credit: NOAA Fisheries
Long-beaked Common Dolphin. Credit: NOAA Fisheries
Long-beaked common dolphins can be found in large social groups in the Atlantic, Indian, and Pacific Oceans. This highly social and energetic species prefers shallow, tropical, subtropical, and warmer temperate waters closer to the coast and on the continental shelf.
Long-beaked common dolphins are closely related to—and easily confused with—short-beaked common dolphins. Once thought to be a single species, the two species differ slightly in size, appearance and habitat preference. Long-beaked common dolphins are less abundant than their short-beaked relatives.
The eastern North Pacific long-beaked common dolphin, the only population found in the United States, is not listed as threatened or endangered. Like all marine mammals, they are protected under the Marine Mammal Protection Act.
Population Status
NOAA Fisheries reviews the status of the eastern North Pacific long-beaked common dolphin in its stock assessment reports. A stock is a group of animals that occupy the same area and interbreed. Although they are less abundant than short-beaked common dolphins, long-beaked common dolphins are not considered threatened or endangered.
Appearance
Long-beaked common dolphins are small, measuring 6 to 8.5 feet long and weighing between 160 and 500 pounds. Males are around five percent larger than females. They have a recognizable dolphin shape with a rounded forehead (known as a melon), a moderately long rostrum, and 47 to 67 pairs of small sharp teeth in each jaw, more than any other dolphin species. Their bodies are sleek and have a relatively tall, triangular dorsal fin in the middle of the back.
Long-beaked common dolphins can be identified by their distinctive color pattern. They have an hourglass pattern created by a dark back, a dull yellow/tan panel on the side in front of the dorsal fin and a lighter gray panel extending along the side from the dorsal fin to their tail stock. A broad dark stripe extends from the lower jaw to the flipper and the dark cape on their back typically includes the eye.
The color patterns of young and juvenile long-beaked common dolphins are generally more muted than in adults. The color patterns can be distinct and vary by geographic and regional areas. Distinguishing the species of common dolphins is most difficult for young dolphins.
Behavior and Diet
Long-beaked common dolphins are usually found in large social groups averaging from 100 to 500 animals, and they are occasionally seen in larger herds of thousands of individuals. These large schools are thought to consist of smaller sub-groups of ten to 30 potentially related individuals or individuals of similar age and sex.
Long-beaked common dolphins are often active at the surface and display various behaviors. These highly social, energetic dolphins are commonly seen swimming rapidly and leaping out of the water at high speeds. They will also swim near the front of ships and ride the pressure waves (or bow-riding) for long periods of time.
Long-beaked common dolphins feed in relatively shallow waters on small schooling fish (e.g., anchovies, hake, pilchards, and sardines), krill, and cephalopods (e.g., squid). Dolphin groups may work together to herd schools of prey. Their diving behavior is thought to be like that of short-beaked common dolphins.
Where They Live
Long-beaked common dolphins generally prefer shallow, tropical, subtropical, and warmer temperate waters within 50 to 100 nautical miles of the coast and on the continental shelf, often in inshore waters. There are discrete populations with limited distribution along coastlines in the Atlantic, Indian, and Pacific Oceans. In U.S. waters, this species is only found along the west coast, and their distribution extends from Baja California, Mexico, northward to central California. Other, discrete populations can be found off the coasts of South America (Peru, Chile, Venezuela, Brazil, and Argentina), West Africa, South Africa, Madagascar, the Arabian Peninsula, India, Indonesia, China, Korea, and southern Japan. The distribution and population center of this species may change with varying oceanographic conditions.
Lifespan & Reproduction
Long-beaked common dolphins have an estimated lifespan of approximately 40 years and become sexually mature at about ten years at around 6.5 feet in length. Breeding usually takes place between the spring and autumn. Calving takes place primarily in spring after a 10- to 11-month gestation period. Every one to three years, females give birth to a single calf that is about 2.5 to 3 feet long and weighs about 20 pounds.
Threats
Entanglement
One of the main threats to long-beaked common dolphins is entanglement in fishing gear (e.g., driftnets, gillnets, purse seines, and trawls). They can become entangled or captured in commercial fishing gear, such as gillnets, seines, trawls, trap pots, and longlines.
Hunting
Small numbers of long-beaked common dolphins have been killed for food and bait in the Caribbean, Venezuela, Peru, West Africa, and other offshore islands. They have been taken in the Japanese drive fisheries as well.
Biotoxins
Long-beaked common dolphins are particularly susceptible to domoic acid poisoning, which is a neuro-toxin produced by algae. When harmful algal blooms (HABs) occur, sardines and anchovies eat the harmful algae, and they are eaten by long-beaked common dolphins. This bioaccumulation of toxic algae can cause seizures and sometimes death in these dolphins and other marine mammals who consume affected prey.
Scientific Classification
| Animalia |
Chordata |
Mammalia |
Cetacea |
Delphinidae |
Delphinus |
capensis |
Last updated by NOAA Fisheries on 09/16/2022
