Bluntnose Sixgill Shark

Bluntnose Sixgill SharkThe Bluntnose Sixgill shark (Hexanchus griseus) is a primitive, common, and distinctive shark that has six gills on each side of the body (most sharks have five pairs on each side of the face). These sharks are also known as the Cow shark, the Grey shark, the mud shark and the Bulldog shark. They have a single (and small) dorsal fin near the end of the body, a blunt snout, and small eyes in front of the mouth. They have six rows of saw-like teeth positioned in the side of the lower jaw. The upper jaw has smaller, curved, single-cusped teeth. They are gray-brown in color and are paler underneath. It averages about 16 ft (4.8 m) long. It ranges from 5 to 16.5 ft (1.5 to 5 m) long.

This shark is primarily a deepwater species living over the outer continental and insular shelves as well as upper slopes. It rests along the bottom during the day to depths of 6,500 feet (2000 m), swimming close to the surface or moving into shallow waters at night to feed. The bluntnose sixgill shark is considered a slow but strong swimmer. Juveniles have been reported from waters close inshore.

Little is known about the behavior and migration habits of the bluntnose sixgill shark due to the depths at which its spends most of its life. However, this species is most often observed as a solitary shark.

It is one of the wider ranging sharks, residing in temperate and tropical seas around the world. In the western Atlantic Ocean, this range includes from North Carolina to Florida (US) and from the northern Gulf of Mexico to northern Argentina including Nicaragua, Costa Rica, and Cuba. In the eastern Atlantic, this shark is found from Iceland and Norway south to Namibia, including the Mediterranean Sea. Its range in the Indian Ocean includes off Madagascar and Mozambique. It also resides in the Pacific Ocean with distribution in the western Pacific from eastern Japan to Australia and New Zealand as well as out in Hawaiian waters. In the eastern Pacific, the bluntnose sixgill shark can has been documented in waters from the Aleutian Islands, Alaska south to Baja California, Mexico and Chile.

Here is a head view: