Atlantic Sixgill Shark

Reaching up to 178 cm in length, the Atlantic Sixgill Shark is a slender cow shark with a pointed head and large eyes. It takes its name from the six gill slits on its sides, which decrease in size toward the tail. This brownish shark carries a single dorsal fin near its rear and features a tail with a notably long upper lobe. While it looks nearly identical to the bigeye sixgill, it has five rows of serrated teeth on its lower jaw rather than the six found in its larger relatives.

These sharks inhabit tropical waters throughout the Caribbean Sea and the Gulf of Mexico. They typically live on continental slopes and shelves at depths of 200 meters or more, though they have been recorded as deep as 700 meters. Their location often depends on age; for example, younger sharks sometimes stay in shallower waters above 350 meters, suggesting they use specific nursing sites. They primarily hunt cephalopods and bony fish, occasionally adding crustaceans to their diet.

Encounters with humans are rare because their deep habitat is difficult to access. Females give birth to live litters of 13 to 26 pups, each measuring about 40 to 45 cm. Although they are not targeted by commercial fishermen due to their soft meat, they are sometimes caught by accident in deep-sea fisheries. Many are released alive, but it is not known if they survive the ordeal. While they are officially prohibited from being brought to shore, the elusive nature of this species makes it difficult for researchers to track their true population numbers.