The frilled shark, a creature of the deep sea, captivates human curiosity due to its ancient appearance. This mysterious animal sparks questions about its nature and whether it poses any danger to humans. Understanding its unique biology, natural behaviors, and secluded habitat clarifies its role in the marine ecosystem.
The Enigmatic Frilled Shark
The frilled shark (Chlamydoselachus anguineus) is often called a “living fossil” because its physical characteristics have remained largely unchanged for millions of years. Its lineage dates back approximately 80 million years. This primitive appearance includes a dark brown, eel-like body that can reach lengths of up to 2 meters (6.6 feet).
A distinctive feature is its six pairs of gill slits, which have a fringed or “frilly” appearance around its throat, giving the shark its common name. Unlike most modern sharks, its mouth is positioned at the very front of its head, not underneath. This deep-sea inhabitant resides on the outer continental shelf and upper continental slope, at depths between 120 and 1,280 meters (390 to 4,200 feet).
Their Natural Prey in the Deep
The frilled shark is an active predator with a diet primarily consisting of soft-bodied cephalopods, such as squid, along with smaller deep-sea fish and other sharks. Its anatomy is well-suited for capturing prey in the dark depths. The shark possesses long, flexible jaws that can open wide, allowing it to swallow prey that is more than half its own size whole.
Its mouth contains approximately 300 recurved, needle-like teeth arranged in multiple rows, designed for snagging and holding slippery organisms. Observations suggest the frilled shark may hunt by coiling its body like a snake and then lunging forward to strike its prey. It can also create suction by closing its gill slits, drawing prey rapidly into its mouth.
Are They a Threat to Humans?
Frilled sharks pose no threat to humans. Their preferred habitat in the deep ocean, far below the depths frequented by swimmers or divers, means direct encounters are rare. The species is not adapted to prey on large animals like humans, focusing instead on smaller marine life.
Most human interactions occur when these sharks are accidentally caught as bycatch in deep-sea fishing nets or when sick or deceased individuals are found at the surface. While their numerous needle-like teeth are sharp, any reported injuries to humans have been incidental, such as scientists cutting themselves when handling specimens.
Conservation and Rarity
The frilled shark is considered rare and has a patchy distribution across the Atlantic and Pacific Oceans. Its elusive nature makes population assessment challenging, but the species is currently classified as “Least Concern” by the International Union for Conservation of Nature (IUCN). Despite accidental captures as bycatch in deep-sea fisheries, current fishing practices are not thought to significantly impact its overall population.
The species has a slow reproductive rate, with a gestation period that can last up to three and a half years. This lengthy development time contributes to its low population growth and underscores the importance of understanding and protecting its deep-sea environment.