Peak of the Elephant Seal Breeding Season
By Point Blue at Los Farallones | January 29, 2010
The last days of January are the peak of the northern elephant seal breeding season on the South Farallon Islands. Most cows have already arrived and given birth on the rookeries, which echo with the sounds of cows calling to their screaming pups and males bellowing to intruders. We can hear the cacophony all the way up at the PRBO house! SEFI’s Sand Flat (pictured on the left), where Rusty is the reigning alpha bull, currently has 73 cows, 52 live pups (9 dead), and 2 weaned pups, including the cow Daniela’s weanling. The Marine Terrace colony has 15 cows, 11 live pups (1 dead), and 2 weaned pups, including the cow Shaye’s weanling, with Flaccido Domingo the alpha defending this harem. Mirounga Beach, where McHammer is alpha male, has only 4 cows and 2 pups, after last week’s massive storms washed out 3 pups and forced 16 cows up to Sand Flat, including the cow Aprile and her pup who are doing fine! On West End, 8 cows and 5 live pups are at Pastel Cave Highlands, defended by Felipe, and 10 cows, 4 live pups (3 dead), and 1 weaned pup are on Shell Beach with Bedlam Boy as alpha bull.
Given that elephant seals must live entirely off their blubber while on land, it is no surprise they spend as much time as possible sleeping. Elephant seals undergo sleep apnea (holding their breath) for up to 25 minutes, enabling them to reduce water loss from respiration and to slow lipid metabolism – the only source of water for a fasting seal.