The animals spend most of their time in the sea, an environment to which they are brilliantly adapted - seals can even rise to the surface to breathe whilst asleep! Feeding mainly on fish and squid, grey seals can dive up to 70 meters (200ft) for a catch and their powerful rear flippers and rudder-like tail ensures they can weather even the wildest storm. Equipped with hefty shoulders, seals are able to haul themselves out of the water and onto slippery rocks, where they can often be seen basking in the sunshine.
On land, the seal's athletic agility in the water is comically reversed, and their two layers of fur and thick layer of blubber make for a lurching, lumbering passage.
Females give birth to fluffy white pups in isolated sea caves that offer some shelter from the elements. After frantically feeding on rich milk for just 15 to 21 days the pups are abandoned by their mothers and must teach themselves to swim and learn to fish through instinct.
Although inquisitive - seals will often approach surfers or swimmers seemingly out of curiosity or a desire to play - they are sensitive animals who can become aggressive when threatened. Colonies should be observed from a discreet distance.
Every grey seal has a unique set of fur patterns on its coat which allows conservationists to carefully monitor behaviour. A protected species, seals are vulnerable to injury through contact with human activity, such as water pollution or fishing nets. The National Seal Sanctuary, in Gweek on the Helford Estuary, was set up in 1958 as a rescue, rehabilitation and release centre for sick or injured seals found in the wild. Today's sanctuary (open every day of the year, except Christmas, from 10 am) is home not just to grey seals but also Californian and Patagonian sea lions, dolphins, turtles and other marine wildlife.
Whales and Dolphins
Most cetaceans are deep sea animals that rarely come close to shore, but some do inhabit coastal waters, notably harbour porpoises and bottlenose dolphins, of which there is a small resident group in the south-west of England.
Just as Keiko the Orca gets trapped in a fishing net in the famous Hollywood blockbuster, Free Willy, so Cornwall's resident population of dolphins is falling prey to the destructive practices of mankind at sea, with the number of dead and injured dolphins washing up on our beaches, usually as a result of entanglement in monofilament nets, rising in sharp contrast to the number of sightings, which is declining.
As well as lone dolphins washing up on beaches there have recently been more serious cases of large groups beaching themselves and dying, most notably in 2008 when at least 26 acrobatic striped dolphins were washed into a creek near Falmouth and died in what was the biggest mass stranding of marine animals seen for 27 years in Britain.
Dolphins primarily travel and hunt using a form of sonar called echolocation (also known as biosonar) which is also used by bats, shrews and whales. The animals emit calls – in the case of dolphins a clicking sound – and then listen back to the echoes of these calls, using them to locate, range and identify objects. Modern technology can interfere with this process, and it is thought that the 2008 stranding may have been caused by local warships that were exercising in the bay.
Dolphins are renowned for their human-like intelligence. Living in groups called pods, they feed on small fish, often co-operating to hunt together. Dolphins are naturally playful and confident animals, who have a good sense of humour and enjoy surfing and meeting people.
It is up to us to work to protect them. For information on how to get involved contact the Whales and Dolphins Conservation Society (WDCS).