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Seal-spotting guidance

Young grey seals on the beach at Horsey, Norfolk
Young grey seals on the beach at Horsey | © National Trust Images/Rob Coleman

Around the UK you can spot grey seals and common seals. They both spend a lot of time at sea but they do come ashore to breed. Coastal walks are a great way to see seals, but you can also view then on a boat trip. Seals may seem common here, but they're more rare globally, so it's important to do all we can to keep them safe. Please follow these tips when watching out for them.

Responsible seal spotting

If you do spot them, please take care not to worry or disturb seals by following these seal-watching guidelines:

Approach considerately

  • Always aim to arrive, watch and leave without the seals noticing you.
  • Walk slowly and quietly to find a safe place where you can sit or lie down to watch the seals.
  • Stay still and quiet, watching for signs that may show you’re disturbing the seals. Whisper if you need to talk.
  • If you see signs of disturbance, quietly move away.
  • Always stick to the designated foot paths and follow local signs.

Getting a good view

  • Use binoculars or a telescope so you can get a better view without getting too close.
  • Please avoid taking your photo with any seals as you may disturb protective females and territorial males, which could result in injury.

Visiting with a dog?

  • Dogs can cause alarm to seals so are best left at home.
  • If you do bring them, please keep dogs on short leads, and stay a safe distance from the seals.

Cause for concern?

  • Pups are occasionally left by their mothers for short times and this is perfectly normal. Pups may also cry, which may sound distressing even if the seal pup is fine.
  • The most important thing to remember is to always keep your distance and not approach any seals as this can cause unnecessary stress.
  • Please keep your distance and do not attempt to move any seal yourself.

If you see an injured seal

If a seal has a visible injury then please contact British Divers Marine Life Rescue (BDMLR) on 01825 765546.

Grey seals and a pup on the beach at Blakeney National Nature Reserve, Norfolk in winter
Seal pup and its mother | © National Trust Images/Justin Minns

Grey seal facts

  • Scientific name: Halichoerus grypus means ‘hook-nosed sea pig’
  • Brief history: Seals are thought to have evolved from otter-like ancestors on the shores of the North Atlantic around 15 million years ago
  • Size: Adults can reach up to 2.5m in length and weigh up to 250kg. Bulls (males) have longer noses, are larger and darker than cows (females)
  • Threats to seals: Being disturbed, becoming entangled in fishing gear and being persecuted. Around 40 per cent of the world’s grey seals breed in the UK.

Life cycle of the grey seal

In the wild, female grey seals can live 30–35 years whilst males live for about 20–25 years. Bulls reach sexual maturity at six years whilst cows are a bit earlier, at three to five years.

When they’re in the sea, seals spend 80 per cent of their time below water, and the rest on the surface breathing. They usually stay underwater for four to eight minutes at a time, although the maximum time recorded was 30 minutes. Seals can reach depths of 30 metres.

They moult their fur annually in the spring, after the breeding season and have a thick layer of blubber to keep them warm, which can be up 6cm thick. This blubber is built up during the warmer months and can be used for energy when required, such as during the breeding season.


Cows become fertile soon after weaning their pups. Bulls hold territories and those that are dominant may mate with over six cows. Protecting a harem is a full-time job, with males often not feeding for several weeks. Mating can take place on land or in water and sometimes sneaky non-dominant bulls will mate with a cow while the dominant bull is mating with another of his harem.


Pregnancy in grey seals lasts for 11½ months with the first 3½ months being delayed implantation. This delay gives cows time to feed up and moult after pupping.

Visitors watching grey seals from the boat on the Farne Islands, Northumberland
Visitors watching grey seals from the boat on the Farne Islands | © National Trust Images/Chris Lacey


Cows give birth to a single pup, weighing around 13.5kg – twins are very rare. Pups are born with a yellow coat, which turns white after a couple of days.

For the first three weeks, pups will feed up to six times a day. The milk contains around 60 per cent fat, helping pups grow very quickly, gaining about 2kg in weight each day. Pups are weaned at around three weeks of age, weighing between 45 to 50kg and it’s at this point they shed their white coat.

The first few weeks

Every year, sadly, several grey seal pups don't survive the first three weeks of life, but this rate of mortality is typical of grey seal colonies. It's tough being a seal pup. Around 30 per cent of pups die within a month and half will die within their first year. Pups are weaned in 18 days, and they quadruple in weight in that time. After this they're abandoned by their mother and spend another 20 days or so in the colony before heading out to sea for an independent life.

What do grey seals eat?

Grey seals will mainly eat fish, squid and octopus, but have been known to also eat crabs. They locate food by sight and sound, but they also have incredibly sensitive whiskers which can help detect vibrations given off by fish swimming. Because of this, even blind seals can survive.

Grey seals are ‘capital breeders’. This means that both the females and males fast during their stay at their colony in the autumn. Over this period all their energy comes from their blubber. A female’s fast can be over 20 days long, while males can fast for over 50 days. This is thought to be one of the reasons seals have pups in the autumn. The longer a male can stay in the colony and defend his territory, the more successful they will be.

Relationship with humans

Commercial hunting for their skins began in the 18th century, however, by 1914 their numbers were dwindling. Grey seals were the first British mammal to gain protection and the Conservation of Seals Act (1970) gave them further protection, to allow numbers to recover.

An adult male grey seal swimming off the southeast shore of Lundy Island in the Bristol Channel, Devon

Where to go seal watching

Coastal walks are a great way to see seals, but you can also view them on a boat trip.

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