White-Beaked Dolphin (marine mammals)


Recognized only as a separate species in 1846, the white: beaked dolphin was among the last of the commonly occurring North Atlantic dolphins species to enter the ce-tological theater. Earlier finds remain obscure because they have been confused with bottlenose (Tursiops truncatus) or common dolphins (Delphinus spp).

The white-beaked dolphin was described twice in 1846, first by the English cetologist Edward Gray based on an animal that was caught off Great Yarmouth, England, and almost simultaneously by the Danish cetologist Daniel F. Eschricht, who described a specimen from the west coast of Jutland, Denmark, under the name Delphinus ibsenii.

A white-beaked dolphin stranded on the Danish west coast.

Figure 1 A white-beaked dolphin stranded on the Danish west coast.

I. Vernacular Names

Vernacular names of the species in most languages depict the white beak: Weissschnauzen-Delphin (German), dauphin avec bee blanc (French), delfin de hocico bianco (Spanish) Witsnuitdolfijn (Dutch), hvidnsese (Danish), kvitnos or hvitnos (Norwegian), and vitnosdelfin (Swedish).

II. Description

The white-beaked dolphin has a robust appearance. The short beak is usually only between 5 and 8 cm long. There is an erect falcate dorsal fin in the middle of the back. Adults grow between 2.4 and 3.1 m long and may weigh between 180 and 350 kg. Males usually grow larger than females. Newborn animals are 1.2 m long and weigh about 40 kg. There are 25-28 conical teeth in each half of the upper and lower jaws.

The coloration is typically black on the back with a white saddle behind the dorsal fin and whitish bands on the flanks that vary in intensity from shining white to ashy gray. The belly and beak are normally white (Figs. 1 and 2). The white beak is sometimes ashy gray or even darker, giving the appearance that the white beak is missing.

III. Distribution

The species is endemic to the temperate and subarctic North Atlantic (Fig. 3). It is frequently sighted in shelf waters and sometimes also dwells in shallow coastal waters. However, it has less oceanic preference than its congener the Atlantic white-sided dolphin (Lagenorhijnchus acutus). Populations in the eastern and western part of its range have been distinguished by means of skull measurements and osteological features.

In the northeast Atlantic it can be found as far north as the White Sea. It is abundant along the Norwegian coasts and in the northern parts of the North Sea and is not uncommon in the southern North Sea along the seaboard of the United Kingdom, Belgium, the Netherlands, Germany, and Denmark. In certain years small schools or individuals may enter the Kattegat. Danish Straits, and even the Baltic proper: a phenomenon believed to be caused by an increased saline influx to the Baltic Sea. The white-beaked dolphin is also known from the French, Spanish Atlantic coasts and may irregularly reach as far south as the Strait of Gibraltar.

In the northwest Atlantic the species seems to be less abundant. The largest concentrations are found off the Labrador coast and in southwest Greenland, but individuals have been encountered as far south as Cape Cod.

IV. Behavior

Schools of up to 30 animals are common, but much larger schools consisting of several hundred or even thousands of animals have sometimes been recorded. The school structure is not known. Animals can be inquisitive and may approach vessels readily. The aerial behavior is very spectacular and typically dolphin-like. Under good sighting conditions the “rooster tail splash” created during speedy swimming is easily visible. The white-beaked dolphin may ride the bow wave of ships and larger whales. The diving behavior is not known in detail. Mixed schools with white-sided dolphins have been recorded.

Close-up of the beak.

Figure 2 Close-up of the beak. 

Distribution of the white-beaked dolphin.

Figure 3 Distribution of the white-beaked dolphin.

V. Reproduction

The available information on reproductive parameters is rather limited. Females reach sexual maturity at about 240 cm in length whereas males mature when around 250 cm long. The age at sexual maturity is not known. Births occur during summer, and gestation lasts between 10 and 11 months. The duration of lactation is not known.

VI. Diet and Natural Enemies

The diet consists of mesopelagic fish species, especially cod, whiting, and other gadids, as well as squids.

Killer whales and also larger shark species probably pose the only natural threat to white-beaked dolphins.

VII. Human Interaction

There is no commercial harvesting of the species. A few animals are shot off southwest Greenland every year. Incidental catches have occurred in trawls and bottom gill nets (mainly young animals).

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