Sharks in the family Hexanchidae, commonly known as Cow Sharks have 1 or 2 extra pairs of gills. Unlike most sharks that have 5.

The 6 and 7 gill sharks are considered the most primitive of all sharks, as their skeleton resembles those of extinct ancestors.

They lack the first large dorsal fin commonly associated with sharks, having only the smaller one near the tail.

Cow sharks range in size from 1.4m to 5m depending on species, and are found in cold, temperate and tropical oceans world wide.

A pair of six gill sharks. All male sharks are distinguished from females by a pair of claspers formed from their pelvic fins that they use during mating.

The Bluntnose Sixgill shark is both the largest, at more than 4.8 m and has the largest litter, 22 to 108 pups, each about 70 cm long.

Blunt-nosed six-gill shark

Meet the researchers

Underwater tagging and tissue sampling

How the research is conducted

What are six-gill sharks?

Puget Sound as a nursery ground

Close-up of six-gill shark

Remarkable shark behavior

Conclusion