Rough-toothed dolphin

Rough-toothed dolphins ( Steno bredanensis )

The Rauzahndelfin ( Steno bredanensis ) is the only member of the genus Steno within the Dolphins ( Delphinidae ). He is found in all tropical waters of the world who have a sufficient depth.

The dolphin was first described by Georges Cuvier in 1823. The name comes from the Greek word shorthand for ' tight ' and refers to the snout shape of animals, which is characteristic narrow. The epithet is dedicated van Breda, who analyzed the writings of Cuvier. The trivial name, however, refers to the narrow lines which are vertical to the teeth of the dolphin.

Features

The Rauzahndelfin is up to 2.50 meters long and reaches a weight of about 150 kilograms. The lips, the throat and belly of Rauzahndelfins are colored pink and white, the flanks light gray and the dorsal fin and the dark gray.

The most characteristic feature is the conical shaped head with the very narrow snout. The pectoral fins ( flippers ) are much further back on the body than other similar dolphins. At sea, there is a likelihood of confusion especially with the Slim dolphin ( Stenella attenuata ) and the East Pacific dolphin ( Stenella longirostris ) and the bottlenose dolphin (Tursiops truncatus ).

Behavior

Like many other dolphins, this kind very social and in groups of 50 to 100 animals occurs in the normal case. The rough tooth dolphins know two ways to go: either swim the individual animals in a loose alliance with different speeds or they join together to form a group and agree direction and speed very accurately coordinate. Instead itself to constantly produce ultrasonic calls for sonar, while most animals prefer to listen while swimming in a group the calls of conspecifics and are based on it. Swimming animals disordered side by side, always produced several individuals at the same time the typical ultrasonic calls. When synchronized swimming contrast, only one animal was usually sounds.

So far no "wave rider " seen in this species, but he often swims with the head and neck above water ( " skimming ").

Dissemination

The exact distribution and especially the population structure of Rauzahndelfins is unknown. Most research results are from the eastern Pacific, where a population size of about 150,000 animals will be accepted. In addition, the animals also live in the warm seas and oceans of the Atlantic, including the Mediterranean, the Caribbean and the Indian Ocean. The sightings find this place exclusively in the high seas off the coasts.

Threat

From a threat to humans is not considered in this species. Some of these dolphins caught in trawls in the tuna fishery, very few were actively hunted.