A batch of sea lion pups crowd one of the rooms at the Pacific Marine Mammal Center. "We once had 28 pups in one pen," says rescue volunteer Priscilla Salazar. "You couldn't see the floor." Since the strandings began, this small facility has rescued more than 300 of the more than 1,300 starving sea lion pups that have washed up in California since January. Researchers think the pups may have weaned early, and are not accessing sardines and anchovies they would normally eat. The reason for the fish disappearance is, as yet, a mystery.