Transcript:

Today on Animal Fact Files we’re discussing cow sharks. There are dozens of classified cow shark species, however, only a handful are alive today. Cow sharks are also known as sevengill and sixgill sharks for the extra pair or pairs of gill slits they possess when compared to other shark species. Most living sharks have five gill slits. Another way the cow sharks differ from other living sharks is their dorsal fin. Cow sharks have only one dorsal fin and this is positioned further back on their body, closer to their tail. In comparison, other shark families have a dorsal fin much closer to the middle of the body. In fact, some other shark species have more than one dorsal fin! Cow sharks are currently considered most closely related to Greenland sharks in terms of living relatives, however their closest family members are extinct. 

Cow sharks look most like their fossilized family members. They have a large, round body; a long, strong upper tail fin; and a much smaller lower tail fin. Their nose may be blunt and round or sharp and pointed depending on the species. They have green, fluorescent eyes and appear gray to olive brown in color, although some reports suggest they can be almost black. Their mouth is positioned on the underside of their head and houses saw-like lower teeth and spearing upper teeth. Cow sharks use their teeth to saw through the flesh of animals too big to swallow whole. Considering these sharks can reach anywhere from 40 inches to nearly 16 and a half feet (100 to nearly 500 centimeters) in length, most prey is bite-sized, but when they scavenge larger animals, such as whale carcasses, their saw teeth come in handy. 

These fish are lumbering giants. They spend most of their time swimming slowly which may be how they got the common name "cow." They can, however, move in quick bursts of speed when needed, such as while hunting. Cow sharks are nocturnal predators; they hunt at night. Not only do they eat squid, crabs, and other bite-sized meals, these sharks also consume dolphinfish, billfish, rays and other sharks. Humans most often come in contact with these brutes during the evening hours, however, they're considered harmless to humans unless provoked. In fact, the international shark attack file by the Florida Museum reports only a single provoked attack on a human since the 1500s. 

Cow sharks are considered a highly migratory shark family. They live throughout all the tropical and temperate oceans of the world. While often described as deep-sea dwelling sharks, it's important to remember that these fish not only migrate horizontally but vertically, too! During the day, cow sharks rest along continental and insular shelves and slopes as deep as 6,500 feet (2,000 m), but at night they move to water as shallow as 100 feet (30 m) to feast. Although they're often large and in charge, some scientists suggest that these fish are eaten by sea lions, other sharks such as great whites, and even killer whales. Humans also catch cow sharks for fish oil and fish meal. 

Cow sharks are believed to be solitary animals, however they may form aggregations during certain parts of the year in order to more easily find a mate. Due to their elusive nature, cow sharks have not yet been caught in the act of mating. It's likely that a male nips at the female's back and fins while he seduces her as the ladies, who are larger, are often seen with scars. When they meet up or even the methods they utilize to meet up are currently unknown. Estimates put their lifespan at 80 years old, and many scientists believe they don't even begin breeding until they're at least a decade in age. Cow sharks have a long gestation period and the eggs hatch inside the mother's body before they're born live. There can be anywhere from 20 to over 100 pups in a litter, however many of them likely perish before they reach reproductive age. 

For more facts on cow sharks, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!