Cow Sharks are 4 species of large, meat-eating fish with sharp teeth. They have no udders, legs or even horns. The whole Cow thing doesn't go at all far. [Why are they called "cow shark"? I don't know] They belong to a family called Hexanchidae, which comes from the Greek for "six arches", referring to the fact that some Cow Sharks have six gill slits. This is unique since just about every other shark in the world has only five gill slits. However, two of the Cow Sharks don't have six gill slits. They have seven. Cow sharks dates back 200 million years to the Triassic period, making them the most primitive species of shark. They can be found in the temperate coastal waters of southern Australia, New Zealand, Japan, east and west coasts of South America; west coast of North America to Alaska and Southern Africa. [not Maryland] These sharks are ovoviviparous, which means they do not lay eggs but give birth to their young. Gestation is approximately 12 months, followed by a year of recovery. Females usually give birth to large litters, of between 80 and 100 pups. ---- The biggest Cow Shark is the BLUNTNOSE SIXGILL Shark. It has six gills! And a blunt nose. They can reach a length of 15.5 feet, though most individuals are somewhat smaller. They've been found in deep, offshore waters all over the world, where they spend the day near the ocean floor at depths of around 6500 ft and swim up toward the surface at night to hunt. The Bluntnose is usually quite slow and sluggish but they can turn on the speed when they need to chase down prey. They'll eat pretty well anything available in the area, including large fish, squid, other sharks or crustaceans. They'll also scavenge carrion if they can find it. Cow Sharks have really cool teeth (cool for them, not so much for the thing they're biting). The upper teeth are long and slim, like the prongs of a fork, while the lower teeth are like saws for cutting through flesh. Those lower teeth are sometimes called "comb-shaped". Cow Sharks don't have a large number of teeth, but the Bluntnose gets by very well with a dozen serrated razor blades in its lower jaw. As is the norm among sharks, Cow Sharks are slow to reproduce. Female Bluntnose Sixgills can take 20 or 30 years before they're old enough to reproduce and it's thought their total lifespan may be some 80 years. Something more unusual about that particular species is a single litter can number over 100 pups! By contrast, the Sharpnose Sevengill will have more like 10 or 20. ---- Belonging to the same genus as the Bluntnose, the BIGEYE SIXGILL Shark also has six gills plus enormous eyes. They reach 6 ft long at most and spend much of their time at depths of about 2000 ft. That does it for the Sixgills. Now for the Sevens! ---- The SHARPNOSE SEVENGILL reaches a maximum length of 4.6 ft, making it the smallest of the Cow Sharks. It compensates for this deficit by being a particularly aggressive and voracious predator. ---- And after the Sharpnose what else could possibly follow but the BROADNOSE SEVENGILL Shark. This species may reach up to 10 ft long and tends to live in shallower waters than the others. Sevengill cowsharks are effective predators and scavengers, often hunting in packs. Appearing slow and cumbersome, they are capable of an amazing burst of speed when attacking their prey. Juvenile cow sharks eat small sharks, bony fish and smaller rays, whilst adults prey on sharks, rays, sea lions, dolphins, seals, bony fish, carrion, octopuses, skates, octopus, molluscs, and crustaceans. Adults only feed sporadically, sometimes once every 5 – 7 days. Newborn pups eat about 10 times what the adults eat and feed far more often. In certain locations, broadnose sevengill cowsharks have been observed spy hopping – holding their heads above water and seeming to look around. This behaviour is rare among sharks but has been regularly observed in Great White Sharks. It may be an adaptation to aid in the capture of marine mammals. Broadnose sevengill sharks tend to ignore divers and are sometimes quite inquisitive, swimming directly towards divers and turning away at the last minute, or swimming over their heads. When visibility is poor, they are a lot more confident and tend to approach far more closely than they would otherwise. They will, however, turn and swim away when intercepted. Unlike Great White Sharks, sevengill cowsharks are not protected in South Africa. [I would prefer the opposite.] Their main predators are great white sharks and larger sevengill cowsharks. - from http://www.realmonstrosities.com/2014/11/cow-shark.html http://www.indigoscuba.com/fascinating-facts-about-broadnose-sevengill-cowsharks/ http://www.fossilguy.com/gallery/vert/fish-shark/notorynchus/notorynchus.htm