HARBOR SEALS – Point Reyes Park CA

HARBOR SEALS of Point Reyes Park

Q-Tips say: YES, go see them. A short drive from the Lighthouse and a slight walk to see the Harbor Seals but worth it. Harbor seals (and sea lions) haul out (come out of the water) almost daily to rest and to warm up. They cannot maintain their body temperature if they stay in cold water all the time because of their smaller size and thinner blubber layer. Northern elephant seals lose less heat than harbor seals because are much larger and have a thicker blubber layer that allows them to stay at sea for months at a time before coming onshore to rest and give birth.

All pinnipeds give birth on land, and that is one fact that distinguishes them from cetaceans, another group of marine mammals. Harbor seals give birth between March and June on tidal sandbars, rocky reefs and pocket beaches. They can give birth on areas which are inundated at high tide because harbor seal pups, unlike most pinniped species, can swim at birth. During the pupping season, mother seals will spend more time onshore nursing pups and resting, for an average of around 10–12 hours per day. The mother harbor seal stays with the pup almost continuously and rarely leaves the pup alone onshore. Mothers can take their pups with them when they go swimming and feeding because pups are adept swimmers.

A mother caresses and nuzzles its baby pup constantly, and for four to six weeks nurses it with her rich milk. The 48% fat content of milk makes the pup gain weight rapidly, and by around 30 days they are weaned. Pups weigh around 11 kg (25 lbs) at birth but when they are weaned they may weigh as much as 22 kg (50 lbs).

During the breeding season, male seals hold territories in the waters adjacent to where females haul out on shore, called maritory. Females are receptive to mating around when the pups are weaned and mating occurs in the water. Male seals will protect their maritory from other males and engage in stylized fighting during the breeding season.

Shortly after the pups are weaned, the seals begin their annual molt of their sea worn fur. The fur sheds much like a dog and the seals turn a luminous color with new fur. The molt period begins around mid-June and extends through July. During this time, seals will spend more time resting onshore because it is energetically taxing. Also, studies have shown that hair follicles grow faster in onshore than in the water. Seals can stay onshore resting for an average of 12 hours per day during the molt compared to around 7 hours per day during fall-winter months.

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