The Hooded Seal

The Hooded Seal
Thirty-five species of seal can be found all over the oceans of the world. They are found throughout the marine environment, from icy polar waters of the north and south poles to the warm waters of the tropics. Much like whales and dolphins, seals are adapted to the marine environment with a streamlined body, limbs modified into flippers and a layer of blubber for insulation needed for the seals located in the poles. They also have a specialized circulatory system that allows them to sustain prolonged dives while feeding which I will say more about during the essay. Different seals also have different characteristics, which make them different from other species; one of these is the hooded seal. The Hooded seal also known as the Cystophora cristata is named for the large elastic sac that extends from the nose to the forehead that expands into a large balloon-like ball. This only occurs in male adult seals. The hooded seal is a large member of the hair seal family and have a black face and a blue-gray coat with random patterns of dark patches. The males and females have may differences, The average length of an adult male is 3 m and they weigh an average of about 300 kg. Adult female hooded seals are smaller though, measuring an average of 2.4 m in length and weighing about 230 kg. Hooded seals are known to dive to over depths of over 900m for more than 45 minutes at a time which is pretty amazing if you compare that to an average human which is a low 5 minutes. The average life span of the Hooded seal is about 30-35 years of age, which is more or less normal for a mammal of that kind, but some stray baby seals may be killed while they are young by predators. Hooded seals are very aggressive looking and aggressive minded compared to much of the other seal species such as the Harp seal. The males show their aggression by inflating the balloon like ball on their face, which can grow to twice the size of a size 5 football. The hood is an enlargement of the nasal cavity, which develops when the seal is in its younger years. When inflated, the hood forms a balloon on the head, when deflated the hood hangs in front of the upper lip. Males also have an inflatable nasal membrane that expands like a red balloon from one nostril. The hood and membrane are mainly used when the seal is fighting for territory and also during fights in the breeding season in order to gather attention of females. The total hooded seal population is currently estimated to be around 650,000.This is a highly migratory species known to wander long distances as far west as Alaska and as far south as the Canary Islands and the Caribbean! Hooded seals are not easily separated into populations, although three groups have been recognized, based on where they breed these are: Off the east coast of Canada in the, in the Gulf of St Lawrence; on the West Ice east of Greenland; and in the Davis Strait between Greenland and Canada. Hooded seals share much of their range with harp seals, although they tend to live farther offshore and feed in deeper water. Because of this, the two species only gather together in the same areas during part of the breeding season. The breeding season is usually from april-june after this, the seals travel long distances to feed. In June-August they reunite on the ice to malt after which they disperse to feed until breeding season begins in late winter. The feeding habits of the hooded seal are very similar to those of the average seal species apart from the Hooded seals feed in deep water diving to depths up to 600 meters .As expected their diet is mainly fish based but their diet varies regionally and includes: halibut, redfish, cod, wolffish, capelin, and herring. Octopus, squid, shrimps and mussels are also eaten depending on where the seal is based. Known predators of the Hooded seal are Polar bears, sharks, and Killer whales. Pups are born between March-April with a well-developed blubber layer and a blue-grey coat, which gives them the nickname ?blue back?. They malt this coat in about 14 months. Newborn pups measure about 1 m and they weigh about 24 kg. The mother only takes care of their newborn an average of 3.8 days after they are born, the shortest lactation period of any mammal. Despite the short nursing stage, the pup doubles in size from about 24 kg to about 47 kg thanks to mother?s rich milk made up of between 60-70% fat. When the females start giving birth, the males begin competing for breeding territory by pushing and fighting each other. Males then wait to mate while the female nurses forming temporary families. When the pup is weaned, the male and female mate in the water. Several hours after mating, the male returns to the breeding territory in search of another female. Hooded seals were commonly killed for their pelts, and baby hooded seals were particularly valued. In 1983, there became a ban on the import of blue back products. Unfortunately, illegal killing has still continued although Commercial hunting of Hooded seals is prohibited in the Gulf of St. Lawrence and in the Davis Strait. Hooded seals are legally hunted in countries such as Norway and Russia, however hunting has been reduced in this seal population in recent years due to decreased access to the seals. The pup is hunted for its hide, while the adult is hunted commercially for its flesh and fat, which are used for animal feed and delicacies in some countries. Hooded seals suffer from entanglement in nets in countries such as Iceland and like other seal species, Hooded seals have been blamed for reduced fish stocks, and the fishing industry has called for culls.

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