Feeding time at the sea lion grotto was always popular and a large crowd would gather to watch. The keeper, who stood inside the exhibit to pass out the fish, generally carried a stick to keep the animals back a reasonable distance. One old female, who was almost totally blind, was more persistent than usual one day and the usual pushes and pokes with the stick were not stopping her. Finally, he gave her a sharp (but not very hard) tap on the top of her head.
The keeper was astounded to see the animal collapse as if she had been shot, topple over, and sink like a rock to the bottom of the pool. He immediately got assistance to pull her out of the water but to their amazement she was already dead.
A necropsy showed that for some reason, either genetic or medical, the bony covering over her skull had been exceptionally thin and had just crumpled in spite of the fact that he hadn’t hit her hard at all. Her skull was so thin, in fact, that the veterinarians were surprised that she had lived as long as she had without bumping into anything due to her blindness.