BEACHMASTERS Breeding
Seal pups are usually born between late August and December, and are fed and cared for by their mothers, who remain with them on land for three to four weeks. Pups are born with a recognisable creamy-white furry coat, their only source of warmth until they build up a thick layer of blubber. Tis takes around a month, aſter which the baby coat becomes pale grey. Grey seal pups feed every five hours and gain
roughly 2kg a day. Teir mother’s milk is ten times higher in fat than cow’s milk, allowing them to triple their body weight in three weeks. Te mother seal can stay on land for up to a month without feeding, although she usually goes hunting aſter three weeks to avoid starvation, aſter losing 30 per cent of her bodyweight to feed her pup. Once the pups are fully moulted, they start swimming and hunting at sea – skills that are largely instinctive and learnt through self-taught practice. Once in the sea, the pups spend weeks experimenting with diving, holding their breath, and chasing small prey. Early dives are shallow and short, gradually increasing in depth and duration as their physiology and confidence develop. Many pups don’t survive their first year, largely because they fail to learn effective hunting skills quickly enough, or they struggle to find adequate prey. Females become fertile and are ready to
mate straight aſter weaning their pup. However, aſter breeding, it can take up to three months for the embryo to implant into the womb, giving the female a chance to rest and recover from giving birth to and feeding her pup. Males fight to occupy parts of the beach to mate with the females. Te successful males are called ‘beachmasters’, and can patrol their territory for up to a month without feeding. Te beachmaster mates with each female in his territory.
A female seal will fiercely defend the area around her pup, seeing
DID YOU KNOW? Each pup has a unique smell and sound, so it’s recognisable to its mother, useful if it gets lost in the colony!
16 Cumbrian Wildlife | November 2025
off intruders with snorts and threatening lunges.
Foraging
Grey seals feed predominantly on fish, crustaceans and cephalopods (a group of marine invertebrates that includes octopuses, squids and cutlefish). Tey need to eat around 5kg of food per day, with most foraging occurring within 100km of the haul-out site. Grey seals have also been known to prey on smaller sharks, common seals and birds. When diving to catch their prey, grey seals make several adaptations to cope with the change of environment and pressure.
1 Vision .
Eyesight is adapted for both terrestrial and underwater environments. Te iris fully opens underwater to let in more light in darker conditions, with the pupil shrinking when the seal is on land to allow it to see almost as clearly out of the water. When the water clarity is low, 43 pairs of sensitive whiskers detect the vibrations from prey, enabling food to be caught.
2 Blood volume .
Seals have a large blood volume, and therefore more haemoglobin molecules to store a greater amount of oxygen. Recent research has shown that grey seals may be able to detect the level of oxygen in their bloodstream and adjust their dive time accordingly so that they never run out of oxygen and drown. Aſter diving, grey seals need time to recover and replenish their oxygen store; this is quick for shorter dives but may require the seal to haul out and rest aſter longer dives.
The grey seal is highly adapted for surviving deep, long dives underwater.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
