Atlantic Grey Seal (Halichoerus Grypus)

Nothing can ever prepare you for your first kayaking encounter with Atlantic Grey Seals. A mixture of fear and delight, as these curious creatures swim incredibly close to you.


Atlantic grey seals reach up to 2.3m in length and weigh between 150-315kg.

The coat colour is often blotchy and can vary from grey or silver to brown. Males have a continuous dark coloured background whereas the females have a lighter background. Juveniles are born with a creamy white natal coat. The nostrils are parallel and the ‘Roman nose’ is characteristic especially in the male Atlantic grey seal.


  1. Adult males in the eastern Atlantic population generally measure 1.95-2.5m in length and weigh 170-310kg, adult females measuring 1.65-2.1m in length and weighing 103-180kg. The western Atlantic grey seals tend to be about 20% heavier.
  2. Pups are born measuring 90-105cm in length and weighing 10-18kg, generally at the lower end of this weight range in the Baltic Sea, and at the upper end of the western Atlantic population.
  3. The mortality rate for pups in their first year can be as high as 30-55%. Females reach sexual maturity at 3-5 years, males at 4-6 years, although males may not attain territorial status until 8-10 years of age.
  4. Atlantic grey seals have been known to dive to depths of 300m and stay underwater for up to 20 minutes.
  5. Females normally live up to 35 years of age, males up to 25 years, individuals in the western Atlantic population generally living longer.
  6. The maximum recorded ages are 46 years for a female, 29 years for a male.
Atlantic Grey Seals playing with kayak in Pembrokeshire

Life Style

Atlantic Grey seals live for 30-40 years.

In autumn females congregate at traditional pupping sites, known as rookeries.

Males then come ashore to compete for sole access to a group of females (a dominant male can secure access to up to 10 females). After mating the Atlantic grey seals disperse.

Most Atlantic grey seals prefer exposed areas such as remote islands, rocky coasts and reefs on which to haul out. Atlantic grey seals can travel long distances between haul out sites while feeding. Many however feed more locally, foraging just offshore and adopting a regular pattern of travelling between these local sites and their favoured haul outs.

Studies have shown that Atlantic grey seals are very individualistic and that their preferred prey, haul-out sites, and feeding locations and techniques differ greatly between individuals. They share much of their range, and some of their haul-out sites, with the more coastal harbour seal.

Members of the western Atlantic population moult from May-June, while the sexes in the British Isles population moult at different times, females from December-March and the males from March-May. Grey seals in the Baltic Sea moult on land or ice from April-June.


The Atlantic grey seals feed on a wide variety of fish, mostly benthic or demersal species, taken at depths down to 70 m (230 ft) or more. Sand eels and cod comprise the seal’s main food but they will eat whatever is available, including octopus and lobsters. The average daily food requirement is estimated to be 5 kg (11 lb), though the seal does not feed every day and it fasts during the breeding season. Atlantic grey seals will also feed on the occasional seabird.


Takes place in the autumn, when the males come ashore to establish territories.

A female may mate with more than one male to produce a pup of around 14kg.

Mating takes place on land, on ice or in the water. Generally, the males enter the rookeries at about the time when the females start to pup and try to gain sole access to groups of females. The successful males are able to mate with 2-10 females.

In locations, however, where the females are more spread out, usually on sand or ice, males are usually only able to mate with one female. There is recent evidence to show that the females have a greater degree of choice in their partners than the males.

Neither lactating females nor dominant males feed during the breeding season, females usually for about 3 weeks and males sometimes for up to 6 weeks. Sub-dominant males may continue to feed since they remain at the periphery of the colonies.

After mating, the Atlantic grey seals disperse and wander widely in order to feed, usually in pelagic waters.

Atlantic grey seal pups

Atlantic grey seal pups suckle for three weeks, gaining 2kg per day due to the 60% fat content of the milk.

After the parents have moved on to find food the pups stay at the rookery surviving on their blubber reserves until the moult has occurred and then they too disperse.


The Atlantic grey seal is currently listed as a protected species under Annex II and Annex V of the European Community’s Habitats Directive and several important sites for Atlantic grey seals have been proposed in EC member countries as Special Areas of Conservation under the Directive.

In August 1999 the Scottish Wildlife Trust purchased the 56-hectare uninhabited island of Linga Holm in the Scottish Orkney Islands, the world’s third-largest island-based Atlantic grey seal breeding colony, as a sanctuary for Atlantic grey seals. The Trust said that it would monitor the seals’ progress, counter the threats that face them, including calls from fisheries interests for culls, and work towards greater legal protection for the island’s grey seal population.

The Atlantic grey seal is also listed as an Appendix III species under the Bern Convention.

You heard it here first… “look but don’t touch”


View the Atlantic Grey Seals at Kayak-King

The Pembrokeshire coast has a 5,000 strong colony of these beautiful creatures. Read more about the Seals here.

The Pembrokeshire coast is a haven for these magnificent creatures. If you would like to view the Atlantic grey seals contact us to book a kayaking tour today.


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