There are grey seals in Yorkshire, living in colonies
on the coast, for example at Ravenscar. They tolerate humans, but not
too close, and not if they feel their route to the sea is cut off. It is
a wonderful privilege to be able to see and photograph them, but with
that comes an obligation to be as discreet as possible, and to avoid
As well as Ravenscar in Yorkshire, there's a grey seal colony at Donna Nook, NE Lincolnshire.
Grey seals: classification
Seals and walruses are within the Order Pinnipedia
('flap-footed'). Grey seals are in the family Phocidae (true
seals), and the genus Halichoerus. The scientific name for the
species is Halichoerus grypus, which is said to mean 'sea pig
with a hooked nose'.
Grey seals are sometimes called Atlantic seals, because they live on
both sides of the North Atlantic Ocean.
Grey seals are 1.4 to 2.5m long, with females averaging 1.8m, and males
2.1m. They weigh 130-144kg. Their eyes are large, and they have long
A thick layer of blubber just beneath the skin insulates seals from the
cold when they are in the water (Britain's Mammals).
Grey seals vs common seals
Grey seals have a longer face than common (harbour) seals, and fewer
spots on their bodies.
Male and female grey seals
As well as the difference in size and weight noted above, there is
considerable variation in grey seals' coloration. Bulls are darker, with
just a few lighter patches. Cows' fur is lighter, with some dark
patches. Seals' coats look lighter when they have been out of the water
for some time, and darken when wet.
The differences in weight and colour between males and females are
examples of their sexual dimorphism - different characteristics in the
two sexes of the same species. Another distinction is the shape of their
faces: bulls' noses have a more prominent bridge - called a Roman or
aquiline nose; cows have a shorter nose without the prominent bridge.
The photo below shows the difference.
Lifespan is up to 20 years for males, and 35 years for females.
Grey seal: habitat and diet
Grey seals live on rocky coasts, and eat fish (especially sand eels),
squid, lobster, and occasionally birds (Britain's Mammals). Their daily
requirement is about 5kg of food (Wikipedia).
Grey seal: predators and threats
Grey seals have no natural predators in UK waters, but are threatened
by pollution and getting entangled in discarded fishing nets.
The UK population is about 200,000, and at the time of writing they are
protected under the EC Habitats Directive.
Grey seals: life cycle
Between late September and December, a female seal gives birth to a
single pup, which is born with creamy white fur, called lanugo.
The mother nurses the pup for 2-3 weeks, during which time it gains
weight quickly from its mother's rich milk. The mother, on the other
hand, loses weight, because she does not eat during this time.
After it is weaned, the pup is left to fend for itself. It stays on
land and moults. Having shed its pup fur, the young seal grows dense,
waterproof adult fur, and it can enter the water - usually at about one
month old. It will then rely on instinct to catch fish.
Male grey seals seek to breed with several females. Some males defend a
group of females, and others try to control access to beaches (Britain's
Mammals). Like female seals, males don't eat during the mating period,
and rely on their stored blubber for energy.
After mating, the gestation period is eleven and a half months,
including a 3 month delay in the implantation of the fertilised egg
(animalcorner). As a result, the female comes back to the same rocky or
sandy place on the coast the following year to give birth and begin the