Hooded seal

The hooded seal (Cystophora cristata) is an arctic pinniped. It is found only in the central and western North Atlantic. It ranges from Svalbard in the east to the Gulf of St. Lawrence in the west.

Hooded seal[1]
Conservation status
Vulnerable  (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Phocidae
Genus:	Cystophora Nilsson, 1820
Species:	C. cristata
Binomial name
Cystophora cristata (Erxleben, 1777)
Distribution of the hooded seal. Breeding grounds indicated in blue.

The male has a peculiar inflatable bladder on the head. This bladder hangs between his eyes and down over his upper lip in the deflated state. In addition, he can inflate a large balloon-like sac from one of his nostrils.^[3] The bulge develops when the seal is four years old. The male can blow up this bulge, so that it is the size of its head.

The hooded seal can live to about age 30 to 35.

Size

Adult males are 2.6 metres (8 ft 6 in) long on average, and weigh 300–410 kg (660–900 lb). Females are much smaller: 2.03 metres (6 ft 8 in) long and weighing 145–300 kg (320–661 lb).^[4][5] The colour is silvery; the body is scattered with dark, irregular marks. The head is darker than the rest of the body, and without marks.

Offspring

Hooded seal pup (next to researcher) on ice in the Gulf of St. Lawrence

Pups are about 1 metre (3 ft 3 in) long at birth and weigh about 24 kilograms (53 lb). They are born on the ice from mid-March to early April. They are born with a slate blue-grey coat with a pale cream color on the belly. They moult after about 14 months. Nursing of the pup lasts for an average of only 4 days. This is the shortest lactation period of any mammal. During the 4 days the pup doubles in size, gaining around 7 kg/day. This is possible because the milk that they drink has a fat content of 60%.^[6] The female pup will mature between ages 3 and 6. The male pup will mature between ages 5 and 7.

References

1. Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
2. Kovacs, K. (2008). "Cystophora cristata". IUCN Red List of Threatened Species. Version 2008. International Union for Conservation of Nature. Retrieved 2009-01-28.
3. Hooded Seal (Cystophora cristata), a Weird Animal Archived 2010-12-29 at the Wayback Machine. Drawfluffy.com. Retrieved on 2011-09-16.
4. Hooded Seals, Cystophora cristata. marinebio.org
5. Hooded seal images Archived 2011-08-30 at the Wayback Machine. arkive.org
6. Iverson, SJ; Oftedal, OT; Bowen, WD; Boness, DJ; Sampugna, J (1995). "Prenatal and postnatal transfer of fatty acids from mother to pup in the hooded seal". Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology. 165 (1): 1–12. doi:10.1007/BF00264680. PMID 7601954. S2CID 8382913.