From: itannman@dogbert.ucdavis.edu (Ann Mansker)
Subject: Critter of the Week: Cystophora cristata
Date: 1999/03/23
Newsgroups: ucd.life


The hooded seal is the largest of the Arctic seals, with the 9-foot-long
adult male weighing in at between 900 and 1000 pounds.  As is typical
for seals, the females are smaller, about 7 feet and 670 pounds.  Solitary
most of the year, the seals gather on sea ice to molt, give birth and mate.
The pups weigh about 50 pounds at birth, and nurse for only 4 days before
their mothers leave them on the ice and head back to sea.  Hooded seal
milk is more than 60% fat, however, and the pups double their weight in
that short time.

Hooded seal pups ( http://www.mmsc.org/info/seal-hooded.html ) are slate
blue on the back and white on their bellies, and are referred to as 
bluebacks by sealers.  The adults are blue-grey with black patches.  An
adult male hooded seal is adorned with a black bladder-like development
of his nasal cavity that can be inflated into a crescent-shaped balloon 
larger than a football that runs from his nose to the top of his head.
When deflated, the hood hangs over the seal's upper lip.  In addition,
the male can close one nostril and inflate his nasal membrane into a
bright red balloon through the other nostril.  Both of these adornments
are used for threat and courting displays
( http://www.magicnet.net/~spirit/seals/hoodedseal.jpg, also two small
images at http://www.greenchannel.com/tec/species/hooded.htm ).