Frilled Sharks - The Oldest Living Shark Species
Frilled sharks (Chlamydoselachus anguineus) have elongated bodies giving them the appearance of eels, or perhaps snakes.
It is the only shark in the family Chlamydoselachidae.
Growing to only 2m (6' 6") in length, these sharks are rarely seen, but have been occasionally fished out of the water as an accidental by-catch.
They have no known uses for man and so are not fished commercially.
As in most shark species, the female attains a greater length than the smaller male, which only grows to 1.7m (5ft 6in).
They may have been mistaken for the mythical sea serpent, much reported by seamen over the centuries.
Frilled sharks are possibly the most primitive sharks in the oceans, dating back to 150 million years virtually unchanged.
They are not considered dangerous to humans, mostly because we seldom meet one, and in fact the only people who tend to see them at all are fishermen and scientists.
Where do frilled sharks live?
Frilled sharks live on the continental slopes of the oceans, in caves and crevices, where they slither out to catch unwary prey.
They have been caught at depths of 1,500m (5,000ft), although they are not usually caught at depths greater than 1000m (3,300ft).
In fact, in the Pacific Ocean off Japan, they have frequently been found at depths of only 50m (160ft), except during the hot months of summer when they travel deeper to find cooler waters.
With their preference for cooler waters, frilled sharks have been found in a wide range of places throughout the world, and even as far north as the freezing waters off Norway.
What do frilled sharks eat?
The jaws of the frilled shark open wide, and their small pointed teeth are razor sharp, suggesting they have the ability to eat prey much larger than themselves.
Frequently, when their stomachs are cut open, there is nothing there. This suggest they either have an extremely fast metabolism, or that they go for long periods without eating.
Scientists have reported finding the remains of other sharks, rays, squid and cephalopods including octopus and cuttlefish in their stomachs, as well as bony fish.
Other names of Chlamydoselachus anguineus
- Frill shark
- Frill-gilled shark
- Frilled shark
- Lizard shark
- Scaffold shark
- Silk shark
What is the classification of frilled sharks?
How do frilled sharks reproduce?
Poor Mrs Frilled has a long pregnancy of perhaps 2.5 years before she gives birth to between 2 - 15 live young, each measuring 40 - 60cm (16 - 24ins).
The average litter is 6.
Frilled sharks are aplacental viviparous, which means that their young grow inside eggs which are kept within their body until maturity.
The young inside the eggs are fed by yolks.
In frilled sharks, the weight and size of the newborn pups do not correspond to the amount of yolk available to them prenatally, suggesting the mother provides some other means of additional nourishment.
This is at present unknown.
Are frilled sharks endangered?
No-one is sure how many frilled sharks there are in the world, but because the increase in commercial fishing activities is resulting on more of them being caught as a by-catch, the IUCN have listed the frilled shark as Near Threatened.