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Showing posts with label seals. Show all posts
Showing posts with label seals. Show all posts

Sunday, November 17, 2013

ELEPHANT SEALS OF SAN SIMEON, CALIFORNIA

Just off highway 1, approximately ten minutes north of San Simeon California, is one of the Largest colonies of Elephant Seals in America. During the month of February, the females spend most of their time on the sand giving birth to the new pups. The best time of year to see this event is mid month as the population is at it's peak. The beach is full of Elephant Seals during this season. The pups weigh 60 – 80 pounds at birth and are 3 - 4 feet long. At this point the new pups are black because they haven't grown their fur yet. The Adult females range from 900 -1800 pounds and are from 9 – 12 feet in length. The males are considerably larger tipping the scales anywhere from 3000 – 5000 pounds and range from 14 to 16 feet in length. Survival rate of the pups in the first year is 37% and by the forth year the rate has decreased to 16%. If they survive the first 4 – 6 years, their life expectancy is approximately 20 years. Weaning of the pups takes about a month. The pups have increased to an astounding 250 – 300 pounds in this first month and have already quadrupled in weight. Female Elephant Seals have grown to full maturity within 6 years while the males continue to grow for a little longer and do not mature quite as quickly as the females.
By March, most of the adults are gone and the weaned pups are left to teach themselves how to swim. At this time, the weaned pups often gather into pods for protection while on land. They also tend to move further up the beach and try to avoid the adult males that have not left yet. As pups, they will spend most of their time sleeping as their bodies begin to change and adapt to sea life. While not sleeping, the males will often spar and practice their fighting skills in order to get ready for adult life and male mating rituals. They square up with each other and bump chests. Elephant Seal pups have also been known to play with objects on the beach such as driftwood or kelp. By two months old, the pups have become proficient swimmers. Half of the weaned pups that leave the area will not survive long enough to return. Their survival generally depends on whether or not they can find food, and be able to avoid predators. Their ability to deep dive plays a significant role in both of these. With the ability to dive as deep as 5000 feet, the only other mammal that can out dive the Elephant Seal is the Sperm Whale. These seals can lower their metabolic rate and divert oxygen to internal organs and the brain. Not only can they store oxygen in their lungs, they can also store it in their blood and muscles, allowing them to dive for more than an hour at a time. Their exterior blubber helps them to maintain a 100 degree internal temperature while on these dives. This often makes it difficult to keep their internal temperature cool while on land. Adults will spend as much as 90% of their time under water. These dives continue during the night as well as the day. In the Summer, Elephant Seals will return to the beaches of San Simeon to molt. The males have often returned from as far away as Alaska, while the females generally wander as far away as the southern end of Canada before their return. While in the water, the females dine on various types of squid. The males are believed to have a much larger variety of diet including rays, skates, ratfish, small sharks, and hagfish. Males are believed to be deeper divers than females. Adult male Elephant Seals can have canines as large as 6 inches long. Females canines can reach 3 inches or more in length.
The Elephant Seals do not have too many natural predators. The Great White Shark, which reaches lengths as great as 20 feet. However they do not dive as deep as the Male Elephant Seal thus having to catch the seal while diving or resurfacing. The Orca or Killer Whale is another danger for the seals. Orcas can get as large as 30 feet in length making them large enough to prey on the seals. Another predator of the Elephant Seal is the Cookie Cutter Shark. Living in the deeper waters, these sharks only reach about twenty inches in length. They move in quickly and take a small chunk of skin or blubber about the size of a golf ball or tennis ball. These bites do not seriously injure the seal. While they are lying on the beach, you can sometimes see these small chunks taken out of them.