Quick Facts

Diet: Carnivore
Avg Life Span in the wild:
Longevity unknown
Size: Up to 15 ft (4.57 m)
Protected Status:
Near threatened
Sixgill Sharks

Little is known about the biology and life history of these mysterious creatures, but the Seattle Aquarium is working to change that.

Sixgills are a common species in deep waters all over the world. Typically found at depths of below 200 feet (and even up to 8,000 feet), they generally avoid shallow waters. However, they have been sighted in waters as shallow as 20 feet in Puget Sound and British Columbia — providing us with a rare opportunity to learn more about these elusive creatures.

Old Timers Most of the world’s shark species have five gill slits; aptly named sixgills have six slits along the sides of their heads and are considered more primitive. Sixgills have been around since before dinosaurs roamed the earth. With their six gill slits and dimorphic teeth — which means the top teeth are different from the bottom — they bear a close resemblance to extinct shark species.

Big bodies, big appetites Sixgills are the world’s third-largest predatory sharks; they’re comparable in size to great white sharks. Like great whites, sixgills are at the top of their food chain. Their prey includes dogfish, skates and bony fishes. In studies done off the coast of South Africa, sixgills were found to have seals and other marine mammals in their stomachs.

Increasing our knowledge: sixgill research at the
Seattle Aquarium
Sixgill sharks are elusive. They generally remain at deep depths and stay away from light. But, thanks the unique opportunity offered by their presence at shallow depths in Puget Sound — and even right under the Aquarium’s pier on Elliott Bay — we are able to study and learn more about our local population of sixgills. Through our research, we are attempting to answer some questions about their population dynamics, home range, breeding patterns and relationships with sixgill populations worldwide. For more information, visit our sixgill shark research page.