Cuvier's beaked whale
The Cuvier's beaked whale or goose-beaked whale (Ziphius cavirostris) is the most widely distributed of all beaked whales in the family Ziphiidae.[7] It is smaller than most baleen whales yet large among beaked whales. Cuvier's beaked whale is pelagic, inhabiting waters deeper than 1,000 feet (300 m). It has the deepest and longest recorded dives among whales at 9,816 feet (2,992 m) and 222 minutes respectively, though the frequency and reasons for these extraordinary dives are unclear.[8][9] Despite its deep water habitat, it is one of the most frequently spotted beached whales.[10]
The genus name Ziphius comes from Greek xiphos "sword" and the species name cavirostris from Latin cavus "hollow" and rostrum "beak", referring to the indentation on the head in front of the blowhole.[11]
French naturalist and zoologist Georges Cuvier first described the species in Recherches sur les ossements fossiles ("Research on Fossil Bones", 1823)[12] based on a skull found on the Mediterranean coast of France at Fos-sur-mer, Bouches de Rhone. He named it Ziphius cavirostris from the Latin cavus for "hollow" or "concave", referring to the prenarial basin, a deep hollow in the skull which is a diagnostic trait of the species. Baron Cuvier believed the skull represented the remains of an extinct species. Later, in 1850, paleontologist and zoologist Paul Gervais found the skull to be identical with that of a whale carcass more recently stranded on a beach.[13]
Cuvier's beaked whale is the only member of the genus Ziphius, and is one of 22 species in the family Ziphiidae.
The body of Cuvier's beaked whale is robust and cigar-shaped, similar to those of other beaked whales, and can be difficult to distinguish from many of the mesoplodont whales at sea. The body of adult males is typically a dark gray, with their head being distinctly lighter, or even white. This light coloration extends along the posterior. Females vary in color from dark gray to a reddish-brown. The skin lightens on female's head to a lesser extent than in males, and does not extend along the posterior.[14] Cuvier's beaked whales are usually born weighing about 500 pounds and between 6.8 and slightly over 8 feet long. Calves are black or dark blue with a white belly. Females reach maturity at an average of 19 to 23 feet long and the males at 19 to 22.5 feet, weighing about 2 to 3.5 tons.[15]
Cuvier's beaked whale is an odontocete — or toothed whale. Males develop two tusks in the right and left corners of their lower jaw and have otherwise a set of peg-like teeth, which may have no practical use or be vestigial teeth only. The females have these same teeth –– or lack of them –– without the two tusks. The tusks are possibly used for dueling between the males, though it has not been observed. They may compete for females, but the tusks may also be used for fighting off threats such as orcas. The adults, especially the males, have many scars along their sides which can be used to identify individuals. The scars are thought, by researchers, to be from battles with males, predators, fights with squid, or cookiecutter sharks, which may score them or punch holes directly in their sides. [16]
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