page_title: Grey seal
section_title: Reproduction
hierarchical_section_title: Grey seal / Reproduction
caption_attribution_description: Halichoerus grypus Deutsch: junge Kegelrobbe English: juvenile Grey seal
context_page_description: The grey seal is found on both shores of the North Atlantic Ocean. It is a large seal of the family Phocidae, which are commonly referred to as "true seals" or "earless seals". It is the only species classified in the genus Halichoerus. Its name is spelled gray seal in the US; it is also known as Atlantic seal and the horsehead seal.
context_section_description: Grey seals are capital breeders; they forage to build up stored blubber, which is utilised when they are breeding and weaning their pups, as they do not forage for food at this time. They give birth to a single pup every year, with females' reproductive years beginning as early as 4 years old and extending up to 30 years of age. All parental care is provided by the female. During breeding, males don't provide parental care but they defend females against other males for mating. The pups are born at around the mass of 14 kg. They are born in autumn (September to December) in the eastern Atlantic and in winter (January to February) in the west, with a dense, soft silky white fur; at first small, they rapidly fatten up on their mothers' extremely fat-rich milk. The milk can consist of up to 60% fat.  Grey seal pups are precocial, with mothers returning to sea to forage once pups are weaned. Pups also undergo a post-weaning fast before leaving land and learning to swim. Within a month or so they shed the pup fur, grow dense waterproof adult fur, and leave for the sea to learn to fish for themselves. In recent years, the number of grey seals has been on the rise in the west and in the U.S. and Canada there have been calls for a seal cull.
  Seal pup first year survival rates are estimated to vary from 80-85% to below 50% depending on location and conditions. Starvation, due to difficulties in learning to feed, appears to be the main cause of pup death.
caption: Seal pup a few days after birth
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