Gray's beaked whale
This species typically lives in the Southern Hemisphere. Many strandings have occurred off New Zealand, but others have happened off Australia, South Africa, South America, and the Falkland Islands.
Gray's beaked whale (Mesoplodon grayi), sometimes known as Haast's beaked whale, the Scamperdown whale, or the southern beaked whale, is one of the better-known members of the genus Mesoplodon. This species is fairly gregarious and strands relatively frequently for a beaked whale. It is notable for being the only beaked whale, other than Shepherd's beaked whale (not a mesoplodont), that has upper teeth.
Gray's beaked whale is a fairly slender member of the genus. The melon on the whale bulges towards the blowhole and slopes down towards the beak. The beak itself is very long and pointed for a beaked whale, and has a relatively straight mouth line. In both sexes there are 17–22 rows of small teeth located towards the back of the mouth, which barely protrude past the gum. In males, there are two small, triangular teeth present halfway down the mouth. The overall coloration is dark on top and light below, and both sexes have a white beak. Females are lighter on top and have additional white marking near the genitals. Adult males often carry linear scars that probably result from fighting, and both males and females may display circular scars from cookiecutter shark bites.
M. grayi are 5.5 to 6.0 m (18-20 ft) long and weigh around 1100 kilograms (2400 pounds). They are believed to be around 2.4 meters (7 feet 10 inches) long when born.
Their preferred diet is primarily deep-water squid, but also benthic and benthopelagic fish and some crustaceans, mostly taken near the sea floor. In a recent study, gouge marks in the seafloor were interpreted to be a result of feeding activities by beaked whales.
Very little is known about the life histories of beaked whales.There are currently no data available on their reproductive rates.
Gray's beaked whale is very gregarious. It has a tendency to strand in large groups, once involving 28 individuals. Other strandings involved five to eight animals. The upper teeth may be used in holding prey, but it is not clear why only this species has them.