The Bluntnose Sixgill Shark

  One of the few remaining prehistoric sharks, the bluntnose sixgill shark is distinguishable from modern sharks by that which gives it it's name: the fact it has six gill slits. Another differentiating feature of the sixgill is the fact that it has no dorsal fin. The only fin on its back is its second dorsal fin, which is far smaller than the dorsal fin on other sharks and lies directly above the anal fin. These sharks spend the majority of their time roughly 2000 metres beneath the surface and are commonly found in near-coastal waters around Britain, Norway, Denmark, New Zealand, Malaysia, Western North America, parts of China, Japan and Australia as well as throughout the Mediterranean Sea.
  This shark grows up to 5 metres long, although it is generally only female specimens that reach such lengths, with males usually stopping their growth at 3.5 metres. Specimens mostly live for around eighty years.
  The diet of the bluntnose sixgill shark consists primarily of flounder and crustaceans, although they have been known to scavenge a meal from an abandoned whale or sea lion carcass. Although large, the sixgill is not a major threat to divers.
  Fossils of similar sharks to the bluntnose sixgill date back to the Triassic Period, with the shark itself thought to have evolved into today's specimen before the extinction of the dinosaurs.

A bluntnose sixgill shark scavenging
for food at night. Note the lack of a
dorsal fin.