The Frilled Shark is perhaps the world’s most peculiar and enigmatic shark species. A “living fossil,” this ancient predator has lived for millions of years with barely any physical adaptations. While most sharks are sleek and slender, the frilled shark is quite different. Its body is eel-like, it has six pairs of frilly gill slits, and it is equipped with hundreds of sharp, needle-like teeth designed to catch slippery prey. Since the frilled shark lives in deep-ocean waters, scientists rarely see this incredible creature. Each sighting provides valuable data regarding its behaviour, biology, and role in the marine ecosystem. This article explores where it lives, what it eats, how it reproduces, and why protecting deep ocean habitats is so important.

Frilled sharks occur throughout the world’s oceans, preferring cold, permanently dark deep-sea environments. Because they inhabit extreme depths, they are rarely observed by scientists or divers.

They have been recorded in:

• Atlantic Ocean
• Pacific Ocean
• Indian Ocean
• Japan
• New Zealand
• Australia
• Norway
• Portugal
• Chile
• South Africa
• Eastern United States

Most sightings occur where the continental shelf drops steeply into the deep ocean. Unlike reef sharks or coastal sharks, frilled sharks almost never enter shallow water voluntarily.

Although some individuals have been recorded at depths of around 1,500 meters, most frilled sharks spend their lives between 500 and 1,500 meters below the surface.

These environments are characterised by:

• Extreme darkness
• Extremely low temperatures
• Very high water pressure
• Limited food availability

Living under these conditions has resulted in the frilled shark developing a slow metabolism and specialised hunting techniques.

The frilled shark looks unlike almost every other shark species.

Unique characteristics

Some of its most recognisable features include:

• Snake-like body shape
• Brown or gray coloration
• Broad terminal mouth
• Six frilly gill openings
• Large pectoral fins
• Tiny dorsal fin positioned far back on the body
• Long caudal (tail) fin extending from the rear of the body

Its elongated body shape also helps conserve energy while swimming through the deep ocean.

One of the frilled shark’s most remarkable adaptations is its approximately 300 trident-shaped teeth. Unlike the broad cutting teeth of species such as the great white shark, these needle-like teeth are arranged in multiple rows and function like fishhooks.

Once prey enters the mouth:

• Escape becomes extremely difficult
• Backward-pointing teeth prevent prey from slipping away
• The prey is swallowed whole

This specialised dental arrangement makes the frilled shark particularly effective at catching squid and other slippery prey.

Unlike fast-swimming pelagic sharks, the frilled shark relies on stealth.

Its hunting techniques likely include:

• Slowly approaching prey
• Lunging forward using its flexible body
• Using backwards-facing teeth to trap prey
• Swallowing prey whole

Several researchers believe the frilled shark strikes much like a snake, using the flexibility of its neck and body to launch a rapid attack. 

Adult females generally grow larger than males.

Typical size

• Average length: 43–52 inches
• Maximum length: approximately 79 inches
• Average weight: up to 18 pounds

Although not exceptionally large, the elongated body often makes the frilled shark appear much bigger than it actually is.

The frilled shark does not lay eggs. Instead, it gives birth to live young through ovoviviparity.

Reproduction facts

• Type of fertilisation: Internal fertilisation
• Method of reproduction: Ovoviviparity
• Gestation period: May exceed three years
• Litter size: Typically two to fifteen pups
• Pup size at birth: Approximately 16–20 inches

Because of its extremely slow reproductive rate, frilled shark populations recover very slowly after declines.

Because scientists rarely observe individual frilled sharks over their lifetimes, their exact lifespans remain uncertain.

Current research indicates:

• Individuals grow slowly
• Sexual maturity takes many years
• The estimated lifespan exceeds several decades

Slow growth and development are common characteristics of deep-sea shark species.

Deep-sea ecosystems, better-managed sustainable fisheries, and increased scientific research will all be essential for the continued survival of the frilled shark, an animal that has survived two to three mass extinction events and millions of years of environmental change. Future generations should have the opportunity to learn about what many biologists consider one of the world’s most ancient living predatory fish. As scientists continue exploring the deep sea, they are expected to make many more fascinating discoveries. Frilled Sharks remind us that many of Earth’s most extraordinary creatures remain hidden beneath the ocean, waiting to be discovered and understood.