Winter is the elephant seals’ season of birthing and breeding at the Piedras Blancas viewing site. The season begins in late November and early December with the arrival of the huge adult males, returning from their journey to Alaska and back, where they have been foraging to bulk up for about three months of fasting. They are at peak size which can be as much as 5,000 pounds. As they come in, one by one, the dominance hierarchy on the beach changes often as they try to set up their territories. One will settle into his chosen spot on the beach, but another male may arrive, announcing his presence with a great bellow and the two will size each other up, first with vocalizing and posturing. One guy may back off, but if not they might fight, banging their chests together and biting necks with their sharp canine teeth.
The pregnant females begin arriving in December and each one selects a comfortable location to give birth. Eventually, each alpha male will have as many as 40 females in his harem, and he expects to mate with each of them when she weans her pup, about a month after it is born. The first pup is usually born in mid-December and births continue through January. Visitors can sometimes witness a birth during this time.
Usually, in less than a week after arriving, a female gives birth to one pup, which weighs from 60 to 80 pounds. The pup may be born head first or tail first, and the birth usually takes less than half an hour. The first thing the mother does is vocalize with her pup, bonding so that they can find each other if they become separated on the crowded beach.
The pups nurse for four weeks and can gain as much as 10 pounds a day on the rich milk, which is over 50 percent fat by the end of the nursing period. For every pound the pup gains, the mother loses two pounds.
The female goes into estrus about four weeks after birthing, mates, abruptly weans her pup, and heads out to sea. It’s important that the pup, now called a weaner, is fat enough to survive after its mother leaves because it will take eight to ten weeks for the youngster to teach itself to swim well enough to head north to forage for food.
The mating season begins about a month after the first births, and there is plenty of action as the alpha males chase other males lurking around the harem and fight for mating rights. February and late January are the best times to view the male action. At the same time, females are squabbling over pups and space, and winter storms are threatening to separate pups from their mothers. It’s not always a pretty picture, but it’s a noisy, exciting time and a rare opportunity for human visitors to observe the seals’ birthing and mating season without disturbing them.
Be sure to visit our web site www.elephantseal.org and the video stream from our webcam.
2 окт 2024
