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Delphinus

2022-09-05 17:19:01 203

Delphinus Life habits and morphological characteristics

The true dolphin is fish-like in shape, about 2 meters long, with the male slightly larger. The body is spindle-shaped, with a slender beak that is more than twice as long as it is wide. There are 40 to 65 small and sharp teeth on each side of the upper and lower jaws, with a diameter of only about 3 mm. The forehead is not as prominent as that of other dolphins, and there is a distinct groove-like constriction at the junction of the forehead and the beak. The dorsal fin is triangular, medium-sized, pointed at the top, and slightly sickle-shaped and bent backwards. The flippers are also triangular, with sharp ends and 5 fingers. The first two cervical vertebrae are fused, and the first 4 to 5 pairs of 14 pairs of ribs are bicuspid ribs. The sternum consists of 4 sections. The back of the body is blue-black-gray, the ventral side is white, and the area between the two is khaki or gray. It looks like an arc is drawn from the top of the flippers to the back end of the dorsal fin, and the

Delphinus Distribution range and habitat

True dolphins are distributed in major oceans, mainly in tropical to warm temperate zones, such as the Pacific, Atlantic and Indian Oceans, as well as the Black Sea. In China, they are found in various fishing grounds in the Bohai Sea and the Yellow Sea, Dasha, Lianqingshi, Zhangzidao, etc., in the Zhoushan, Wentai and Haijiao fishing grounds in the East China Sea, in the Beibu Gulf, Beihai and Hainan Island waters in the South China Sea, and in the waters near Keelung, Taoyuan and Penghu in Taiwan.

Delphinus Detailed Introduction

Common dolphins are called common dolphins in English. There are two species (long-beaked common dolphins and short-beaked common dolphins), with a total of four subspecies.

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Common dolphins belong to the order Cetacea, the family Delphinidae, and the genus Delphinus in taxonomy. There are two species in this genus, the short-beaked dolphin and the long-beaked dolphin. They have a triangular light-colored area in the center of their dorsal fins and a deep groove on the left and right of the palate of their maxilla. These characteristics are enough to distinguish them from other animals in the Delphinidae family. Due to their wide distribution range, local variations are also great, especially the length of the beak and the body color vary greatly, so that those that were once classified as different species actually belong to the true dolphin.

True dolphins often form groups of dozens or hundreds of them. They are very attached and agile. They feed on fish and squid, especially schooling fish such as herring, sardines, mackerel, yellow croaker, horse mackerel, and hairtail. When chasing schools of fish, they often make frequent ups and downs on the water surface and jump out of the water from time to time. They swim very fast, with an instantaneous speed of up to 30 nautical miles (about 55km/h). Sometimes they follow behind fishing boats and ships, or sway in the waves at the bow of the ship.

Spring and autumn are the main mating seasons for true dolphins. Females give birth every 2-3 years. The gestation period is about 10-11 months. The length of the cubs at birth is 75-85 cm. The lactation period is more than 1 year.

Listed in the 2008 Red List of Endangered Species of the World Conservation Union (IUCN) ver 3.1

Short-beaked true dolphin (Delphinus delphis) - Least Concern (LC).   Long-beaked true dolphin (Delphinus capensis) Data Deficient (DD).

Listed in the second level of the "List of National Key Protected Wildlife in China".


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