After the bulls settle who's going to rule the beach for the next few months, the females show up in late December and gravitate to the alpha males, forming harems the dominant bulls will spend the next few months defending. Smaller bulls will hang around the edges of the harems, obliging the big guys to run them off -- watching two-ton beasts with no legs chase try to chase each other on land is one of nature's great comedy sketches.
The females arrive ashore pregnant from last season's amorous adventures and mate after giving birth to their pups, which, fortunately, are about a thousand times cuter than their nose-dangling fathers.
By the end of March most of the elephant seals have returned to sea, fattening themselves up to do it all again next winter.
(Weather note: veteran elephant seal watchers advise that cool, cloudy days promise the best seal action -- they try to preserve energy on hot days but they're much more mobile on chilly ones).