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Friday, January 28, 2011

Elephant Seals & Pups at Año Nuevo State Reserve

My spouse, Mary Jane, and I visited Año Nuevo State Reserve, a California state park on the San Mateo County coast, on January 26.  This is the largest mainland breeding colony in the world for the northern elephant seal (Mirounga augustirostris).  We wanted to witness the peak of winter calving, with hundreds of females and pups greeting us on the 3-mile guided hike.

   All Images Copyright by Tom Debley, 2010            

The day was unseasonably warm, which makes life uncomfortable for the elephant seals.  Their blubber keeps them warm in cold water, and sand flipping helps them keep cool on land.  They toss it over their bodies so that the sand acts as a sun screen. At the right and below are examples.

Mothers and pups recognize each other through vocalizations. Immediately after birth, the mother and pup become familiar with each other by sniffing at and calling to each other.
The reason? Territorial disputes and stormy surf conditions can separate a mother and pup. This intensifies the need to recognize vocalizations or the pup faces almost certain death.

A pup weighs about 70 pounds at birth. The female nurses her pup for 28 days. She loses about two pounds for every pound the pup gains. An elephant seal's milk is extremely rich.  It reaches 55 percent fat during the final week of nursing. As a result, the mother loses 300 to 500 pounds.

A pup weighs about 300 pounds when it stops nursing. Mom, after mating again, returns to the ocean.
Here are some additional photographs:

Moms & their pups.

Females 'argue' over territory.


1 comment:

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