The frilled shark is an ancient deep-sea creature, often called a “living fossil” due to its primitive appearance. Its eel-like body and frilly gill slits distinguish it from most other sharks. Much about this animal’s life in the deep sea remains mysterious.
The Frilled Shark’s Deep-Sea World
Frilled sharks inhabit the deep waters of the Atlantic, Pacific, and Indian Oceans, typically found near continental and island shelves and upper slopes. They commonly reside at depths from 120 to 1,280 meters (400 to 4,200 feet), though observed deeper and occasionally closer to the surface. Males grow up to 1.7 meters (5.6 feet) and females up to 2.0 meters (6.6 feet).
The frilled shark is an ambush predator, known to lunge at prey like a snake and swallow it whole. Their diet primarily consists of cephalopods (especially squid, making up about 60% of their meals), bony fish, and other sharks. Their deep-sea environment is characterized by perpetual darkness, cold temperatures, and immense pressure. They possess specialized features like flexible jaws and needle-like teeth to capture elusive prey.
The Mystery of Observed Predation
Understanding what preys on frilled sharks is challenging due to their deep-sea habitat. Direct observations of predation events are extremely rare in scientific literature. The species is rarely encountered alive; most information comes from specimens caught as bycatch or found deceased.
A lack of observed predation does not definitively indicate an absence of predators. Many captured frilled sharks have missing tail tips, suggesting escape from attacks by other marine animals. This anecdotal evidence points to potential interactions with larger predators.
Unraveling Potential Predators
Larger predators sharing the frilled shark’s habitat could prey upon it. This includes large deep-sea sharks like the Greenland shark, over 6 meters (21 feet) long, known to consume other sharks. Pacific sleeper sharks, also large deep-water ambush predators, eat fish, cephalopods, and marine mammals, making them potential threats.
Beyond other sharks, very large marine mammals that dive deep may also be predators. Sperm whales routinely hunt in deep waters, eating squid, fish, and sharks. Studies of sperm whale stomach contents have revealed large sharks, indicating they can consume them. While frilled sharks are effective predators, they could become prey for larger, more powerful creatures in the same deep-sea food web.