TRUE SEALS

Ringed Seal (Pusa Hispida)

The Ringed Seal (Pusa hispida) is named for the diagnostic ring-shaped patterns on its pelt. Distributed widely across Arctic and sub-Arctic waters, it usually dwells on ice. While population estimates are difficult and numbers overall are thought to be good, 1 subspecies has been assessed to be Vulnerable, while another is actually Endangered according to the IUCN. With retreating ice, this species is likely to be at further threat. Estimated population size = 3,000,000.
P. hispida are stocky, but reasonably small true seals (males up to 1.65 m long/ 110 kg, females up to 1.4 m/ 70 kg). They have a short neck and small rounded head with a cat-like face, and short fore and rear flippers. The fore flippers contain sturdy, dense claws that are used to scratch breathing holes in thick ice. As already mentioned, they have distinctive silver ringed patterns on their dark grey or black backs which develop with age, and paler grey through to almost cream-colour undersides.
Feeding behaviour:
The preferred diet of P. hispida are small, schooling fish, and to a lesser extent, small invertebrates. Like other species, prey choice is governed by seasonal availability and location, with only 2-4 key species predominating in an area. Individuals will perform deep dives to take benthic invertebrates when necessary, while in more productive times they will scour the edges of sea ice for fishes such as cod. Freshwater subspecies feed predominantly from aggregations of small fish.
Breeding behaviour:
Sexual maturity – males 5-7 years old/ females 3-7 years old. However males probably do not successfully breed until after this time.
It is thought P. hispida are polygynous breeders and that males establish underwater territories. Mating occurs in April/May but implantation in the uterus is delayed until August/September. The females build lairs made from snow on the top of sea ice in which to pup and this occurs during March/April. These protect the white-coated youngsters from the cold and elements when they are first born. Weaning takes around 39 days, during which time the mother will only feed occasionally, and moulting season follows in mid-May to mid-July, where the female cannot feed, so they lose a lot of weight during this period. The pups however will spend half their time in the water, learning to dive and efficiently avoid predation, as they are extremely vulnerable on the ice. Once the pup is ready (around 20kg) it will already be familiar with diving and feeding. P. hispida has been known to live up to 45 years of age, though commonly reaches around 30.
There are five subspecies of P. hispida:
Arctic Ringed Seal (Pusa hispida hispida)
Okhotsk Ringed Seal (Pusa hispida ochotensis)
Baltic Ringed Seal (Pusa hispida botnica)
Ladoga Seal (Pusa hispida ladogensis)
Saimaa Ringed Seal (Pusa hispida saimensis)

Photos: NOAA

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