Bluntnose Six Gill Shark (Hexanchus griseus)
… often simply called the “Cow Shark”, is a large shark, growing to more than 5.4 m (18 ft) in length. Although sluggish in nature, the bluntnose sixgill shark is capable of attaining high speeds for chasing and catching its prey. Because of the bluntnose sixgill shark’s large and diverse range they have a wide variety of prey items.
The bluntnose sixgill shark is a member of the Hexanchidae family. Many of its relatives are extinct. The living species that are closest genetically include the dogfish, the Greenland shark, as well as other six- and sevengilled sharks. There are more closely related relatives in the fossil record than living species. Some of the shark’s relatives date back to 200 million years ago. This shark is a notable species due to both its primitive and current physical characteristics.
This species typically inhabits depths greater than 90 m (300 ft), and has been recorded as deep as 1,875 m (6,150 ft). Like many deep-sea creatures, the bluntnose sixgill shark is known to undertake nightly vertical migrations (travelling surfaceward at night, returning to the depths before dawn)…
(read more: Wikipedia) (images: T - NOAA, B - Graham Bould)