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Seals can be social creatures, when the time is right. Some seals are more communal than others, but everybody wants company when it’s mating season.
Most seals breed in colonies that are noisy and active places designed to meet and greet the opposite sex and rear their pups. When they’re done with the mating and child-rearing phase in the summer, seals tend to spread out for more solitary winter endeavors.
Seals typically forage and hunt alone. Though most Antarctic seals are not truly migratory, pack-ice seals – like Ross and Leopard seals – tend to follow the movement of the ice and available food. Some fur seals are known to migrate, but on South Georgia Island they just disperse to their private patches of inland tussock grass.
Southern Elephant seals winter at sea, but they gather on summer beaches for breeding and molting. In fact, Elephant seals just can’t get close enough. Even on the broadest, most spacious beach, they’ll lay next to each other so that they’re touching and then grumble about the smelly guys molting next to them.
[TRIP TRIVIA: You’ll never forget the first time you visit an Elephant seal “pod.” When they’re not arguing or tending pups, these seals crowd into pods that generate a smell that’s simply overwhelming! The snoring and snorting noises can be memorable, too. Humans might even find these social scenes distasteful!]
Fur seals feed and travel in the water, but they breed in large colonies on land. The males arrive early and are especially territorial, hoping to be the first to woo and win incoming females. Territories often provide some naturally defensible boundaries, such as rock outcroppings, to keep out trespassers.
Weddell seals gather around breathing holes during breeding season. The males defend their water holes against each other while their women-folk rear pups on the ice. These groups don’t entirely disperse once the breeding is over, but the seals naturally spread out as more breathing holes open up in warmer weather.
Crabeaters and Leopard seals are exceptions to the colony rule, and mother-pup pairs tend to stay fairly isolated from others. Crabeaters breed on the pack ice in solitary pairs and practice serial monogamy. The male stays with the female until they mate, and then he moves on to the girl basking on the ice floe next-door.
Leopard seals are also anti-social in their breeding habits. The only groups they appear to form are between mothers and pups and between mates, which are short-lived relationships.
Ross seals are the most mysterious because of where they live in the pack ice. They probably breed and birth much like the Crabeaters and Leopard seals.
Early in the breeding process, male seals compete fiercely for female attention and are typically obsessed about keeping their females to themselves. Depending on the species, they use different methods to battle competition and become top seal. Basically, they make a lot of noise, beat each other up, and spend a lot of energy keeping other suitors at flipper’s length.
Fur seals are particularly aggressive around mating time. They bark and posture and charge other males to defend a territory where they might mate with up to a dozen female partners per season.
Male Elephant seals use their voices to intimidate other males. A male features a “trunk” – a huge and inflatable nose that grows with age – that he fills with air to make it erect. When he roars, this special nasal resonating chamber makes him sound bigger and badder than all the rest.
Of course, talk is cheap. There is plenty of physical fighting at the beginning of breeding season and even during the next two months, when Elephant bulls stay on the beaches to maintain their places in the hierarchy. Female Elephant seals congregate in harems of around 40 to 100 individuals that the dominant bulls attempt to manage.
Female seals give birth in the spring or summer after gestating for around a year. Antarctic seals don’t mate until the pups from the previous year are born, and most earless (true) seals wait to mate until the females are done lactating.
Though females become pregnant immediately after mating, the embryo goes into a holding pattern for 3-4 months – it stops growing after a few days and doesn’t implant in the uterus for several months. This spring/summer birthing/breeding cycle gives the pup its best chance of survival.
The amount of time a seal mom spends with her pup depends on the species. True seal pups are dependent for a short period of time – anywhere from four days to several months. Because females stop lactating before they mate, the suckling phase must be short.
Most females nurse pups for about a month. Many true seal moms fast while they nurse their young, which means that they lose a lot of weight while their pups gain it. Seal milk contains an amazing amount of nutrients and energy. It is 30 to 60 percent fat with at least 5 to 15 percent protein. Pups can gain up to 25% of their birth date each day, they can triple their body weight from birth to weaning.
Weddell seal pups wean just under 2 months, which is longer than most true seals. Mothers teach pups to swim within a week to 10 days of being born. Mom uses tough love – she pushes the pup into the water and holds him under until he learns to hold his breath.
Female fur seals are ready to mate within a week of giving birth. They’re different in that they enjoy regular meals while they suckle, which can last up to four months. Pups wait near their birthing place and moms find them again by sound and smell. Fur seal pups are dependent the longest of all Antarctic seal babies.
Most seals aren’t born with enough blubber to stay warm, so instead they rely on “lanugo” – very fine and thick baby fur. Pups are born with all of their hair follicles, so that a pup’s fur is denser than an adult’s.
After pupping season, the kids are on their own. Mom’s not around to show them ropes once the pups take to the water for good.
[TRIP TRIVIA: Based on extensive research conducted by rigorous expeditions to Antarctica, scientists and tourists alike agree that seal pups are quite possibly the cutest creatures on earth. The best time to see fur seal pups on South Georgia is early December. Book your ticket now.]