The frilled shark has been swimming in the deep ocean for millions of years and is one of the most primitive sharks alive today.
With its strange eel-like body, frilly gill slits and rows of needle-sharp teeth, it thrives in the cold, dark depths of the ocean. Because of this, humans have rarely seen it alive in its natural habitat.
What is a frilled shark?
The frilled shark (Chlamydoselachus anguineus) is a deep-sea species that belongs to one of the most ancient branches of the shark family tree.
It dates back around 80 million years and is considered a living relic of the Cretaceous period. Its unique appearance (which has earned it the nickname 'lizard shark') and slow evolutionary change make it a 'living fossil' – an organism that closely resembles a species known only from the fossil record.
What do frilled sharks look like?
Frilled sharks can reach lengths of up to two metres. They have a long, slender body resembling an eel, with a short, rounded snout and a wide mouth that opens further than most sharks.
Six pairs of gill slits are edged with frilly skin folds, giving the species its name. Their teeth are arranged in three rows of trident-shaped points, ideal for gripping slippery prey.
Their dorsal, pelvic and anal fins are small, and their brownish-grey skin blends perfectly with the dim ocean environment.
What do frilled sharks eat?
Frilled sharks feed mainly on squid, but will also take bony fish and other sharks. Their flexible jaws and long, needle-like teeth allow them to seize prey that is almost as large as themselves.
They may lunge forward like snakes to capture food (though humans have never actually seen this behaviour in the shark's natural environment), and their stomach contents sometimes show squid swallowed whole. In the deep sea where meals are scarce, frilled sharks take every opportunity to feed.
Where do frilled sharks live?
This species is found in deep waters across the Atlantic and Pacific Oceans, typically between 200 and 1,500 metres. They favour continental slopes, submarine canyons and seamounts where prey is more abundant.
Because of their depth range, they are rarely encountered by divers and are usually seen only when caught as bycatch in deep-sea fisheries or filmed by submersibles.
Are frilled sharks dangerous to humans?
Frilled sharks pose no threat to humans. Their deep-sea habitat means they have little to no contact with people, and their diet is focused on marine animals. Rare captures have shown that they are sluggish and unlikely to attack unless provoked.
Are they under threat?
While not targeted for commercial fishing, frilled sharks are vulnerable to deep-sea trawling and longline fisheries, which catch them accidentally.
They have low reproductive rates, producing small litters after an unusually long gestation period that may last up to three and a half years. This makes population recovery slow. The International Union for Conservation of Nature currently lists the species as Least Concern globally, though local populations may be at risk where deep-sea fishing is intense.
Five fun and weird facts about frilled sharks
- Frilled sharks have the longest known pregnancy of any vertebrate, lasting up to 42 months.
- They can open their mouths wider than most sharks relative to body size.
- They have about 300 teeth, perfectly shaped for gripping slippery prey.
- They swim in an eel-like motion, flexing their entire bodies.
- The first live footage of a frilled shark was only recorded in 2004.
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