What is a Cow Shark?

Cow sharks belong to the order hexanchiformes, an order distinguished from other sharks by the number of gills. A cow shark has either six or seven gills, while other sharks have five. Living in temperate and tropical areas of the Atlantic, Indian, and Pacific Oceans, cow sharks typically inhabit deep waters and have been found down to 6,150 feet (1,874 m) but more commonly occur in depths of between 150 feet (45 m) and 300 feet (90 m).

There are four species of cow sharks, and they are a diverse group. The smallest of the cow shark family is the sharpnose sevengill, which typically has a maximum length of only about 4.5 feet (1.4 m); the bluntnose sixgill is the largest cow shark, reaching a mature length of more than 15.5 feet (4.8 m). Belonging to the same genus as the bluntnose sixgill is the bigeye sixgill. The broadnose sevengill is the only species of cow shark that can commonly be found in the shallow coastal waters of the oceans it inhabits, and consequently is the most studied of all the species. The sharpnose sevengill and the bluntnose sixgill have both made the International Union for Conservation of Nature Red List of Endangered Species.

Each of the cow shark species is characterized by one dorsal fin far to the tail end of the shark, as well as an anal fin and a stout, rounded body. The powerful mouths have a distinct overbite, and the top jaw is filled with thorn-like teeth, while the teeth in the bottom jaw have a unique comb shape. Cow sharks give birth to live young, with average litter sizes ranging from 22 to 108 pups. Parents come to shallow waters to give birth in the spring and early summer.

In sharp contrast to the docile nature their name might suggest, cow sharks are aggressive hunters and prey on other marine animals from fish, squid, seals, and dolphins to other sharks. Broadnose sevengills have been observed hunting in packs, displaying methods of cooperative hunting unusual in sharks. Known for their curiosity, they have been observed swimming boldly up to divers. This has resulted in confrontations between humans and sevengills, particularly those found in the kelp forests off the coast of Cape Town, South Africa. Scavengers as well as predators, they have been known to attack humans in shallow coastal waters, and human remains have been found in the stomachs of dissected cow sharks.

A cow shark is a member of the Hexanchiformes order, known for its additional pairs of gill slits—six or seven compared to the typical five on most sharks. They have a distinctive, elongated body shape and a broad head. Cow sharks are considered more primitive than other sharks due to these ancient features.

Cow sharks are widely distributed in temperate and tropical oceans around the world. They are often found in deep waters, close to the continental shelves. Some species, like the broadnose sevengill shark, can also be found in shallower bays and estuaries.

Cow sharks are opportunistic predators with a varied diet that includes fish, smaller sharks, rays, squid, crustaceans, and carrion. Their powerful jaws and saw-like lower teeth allow them to tackle a range of prey, including larger and tougher targets.

While cow sharks are generally not considered a significant threat to humans due to their deepwater habitats, there have been some reports of aggression from the broadnose sevengill shark. However, encounters are rare, and incidents are infrequent compared to more aggressive species like the great white shark.

Cow sharks are ovoviviparous, meaning their young develop in eggs that hatch inside the female's body. The pups are then born live. This reproductive strategy is relatively rare among sharks and allows for the birth of well-developed, independent young, which increases their survival chances.

Conservation status varies among cow shark species. For instance, the broadnose sevengill shark is listed as Near Threatened by the IUCN due to fishing pressures and habitat degradation. Conservation efforts are crucial for these ancient species, as they often have slow growth rates and low reproductive rates, making them vulnerable to overfishing and environmental changes.