After suckling her pup for about twenty-eight days, the mother elephant seal shuts off the supply of rich milk.
The mother weans her pup abruptly so that she can return to the sea and replenish her depleted nutritional supplies after having fasted since coming ashore to give birth.

In so doing, she will leave her pup, now re-named ' weaner ', to fend for itself on the beach.
( Some weaners, usually male ones, try to get more milk from other females.
If they succeed, they can balloon to enormous sizes, weighing up to five hundred pounds and earning the name super-weaner. )