Frilled Shark which is one of the oldest living shark species resembles the eel in appearance. According to fossil evidence frilled sharks were there even more than 95 million years ago and hence they are considered as “living fossil”. They are called frilled sharks because of their frilly skin which covers the six gill slits. This type of shark has characteristic long and thin body and a long tail fin. Frilled Sharks belong to the family of Cow Sharks, also known as Hexanchiformes. Though there is not much information regarding the trends of frilled shark population, now it is considered as one of the species that are facing the threat of extinction. While squid is the main food of frilled sharks, they also eat fish and other types of sharks. This primitive shark species live under the sea of Southeast Asia, West Africa, Chile, Caribbean, off North America, Spain, Southeast Australia and New Zealand.
The frilled shark is one of the strangest species that live in deep sea and is distributed almost worldwide. Though they are found at isolated locations their population is not concentrated anywhere. This mysterious ancient type sharks are still surviving. Frill Sharks could survive even after millions of years mainly due to following reasons.
(1) Frilled Sharks are accustomed to live in deep sea. They live 500 – 1500 meters below the surface and rarely come up to higher level. Since they live close to the sea bed, humans need not fear about these sharks. As a result, they are not attacked by humans.
(2) Though frilled shark is used to prepare fishmeal, it is caught only as a by-catch variety by commercial fisheries the world over. This is also a reason for the survival of Frilled Sharks.
(3) The frill sharks have few predators and they have the threat of predators only when they come to the higher levels in the sea. Hence, the absence of predators facilitated the survival of frill sharks.
(4) No fisheries in the world specifically target frill shark since they live in deep sea.
(5) Frilled Sharks eat squids, varieties of fish and other sharks. Hence they never starve for food.
(6) Many captured specimens of frilled sharks were found with empty stomachs indicating that they remain alive for a long time without food.
(7) Since the frilled sharks live close to the sea bed they are not easily affected by pollution, changes of habitat and climate changes. They are not subjected to stresses.
(8) Frilled Shark has the longest gestation period up to 3 ½ years. The baby sharks hatch from eggs and these eggs are kept inside the body of the female frilled shark. The baby shark is fed by its mother on the yolk until it is born. In this way the baby sharks are adequately protected. Both the ovulated eggs and embryos are kept inside thin capsules. The egg will open only after the embryo is grown about 8cm long. While the embryo is fed by the yolk the embryo receives extra nutrition from its mother.
(9) The frilled sharks come near to the surface only during night time and as a result they are not seen by fishermen.
(10) There are not too many similarities among Frilled Sharks and the shark varieties that are extinct. Hence frilled shark is a relatively recent species and hence it is not extinct.