T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Whale (Blainville's beaked whale) Mesoplodon densirostris

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Ziphiidae
Genus: Mesoplodon
Species: M. densirostris
Binomial name: Mesoplodon densirostris
Common name: Blainville's beaked whale 

Blainville's beaked whale (Mesoplodon densirostris is a species of beaked whale is found in tropical and warm waters in all oceans and its known to range into very high latitudes. Strandings have occurred off Nova Scotia, Iceland, the British Isles, Japan, Rio Grande do Sul, South Africa, central Chile, Tasmania, and New Zealand. The species does not migrate. It inhabits waters up to 1,500 m deep. 

The body of Blainville's beaked whale is robust, but also somewhat compressed laterally compared with other mesoplodonts (small beaked whales). The males have a highly distinctive appearance, the jaws overarch the rostrum, like a handful of other species, but does it towards the beginning of the mandible and then sloped down into a moderately long beak. Before the jaw sloped down, a forward-facing, barnacle infested tooth is present. One of the more remarkable features of the whale is the extremely dense bones in the rostrum, which have a higher density and mechanical stiffness than any other bone yet measured. At present, the function of these bones is unknown, as the surrounding fat and the brittleness of the bone make it unlikely to be used for fighting. It has been suggested that it may play a role in echolocation or as ballast, but without sufficient behavioural observation, this cannot be confirmed. The melon of the whale is flat and hardly noticeable. Colouration is dark blue/ grey on top and lighter grey on the bottom, and the head is normally brownish. Males have scars and cookie cutter shark bites typical of the genus. Males reach at least 4.4 m and 800 kg, whereas females reach at least 4.6 m and 1-tonne in weight.
The Blainville’s beaked whales feature long dive times and short surface intervals. They are among the longest and deepest divers of any cetacean, with the deepest documented dive being 1,599 m. The species dives primarily to forage for food in the deep ocean, usually diving >800 m when foraging. It is thought that foraging at these depths helps to avoid predators that hunt in mid-depth waters, such as large sharks or killer whales.

Blainville's beaked whales do not capture prey by their jaw. They use suction feeding to capture prey. They create low pressure in the mouth by retracting the tongue, and using throat grooves to expand throat volume. This creates a lower pressure in the mouth than the surrounding waters, allowing the whale to suck in water and whole prey. They feed primarily on squid, fish and other invertebrates. It probably feeds mainly on squid.  


Diagram showing a whale and scuba diver from the side: The whale is two and a half times longer than a human.



The blue shading shows the cosmopolitan range of the Blainville's beaked whale 


Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/