[shams93]

It makes sense, humans are not normal food for sharks. However once you're dead you're just floating meat in the water, the shark can take you without risking any injury to itself. Sharks are more intelligent than we generally assume, most shark attacks are not to eat people, they take a chunk out of a person by mistake.

[mannykannot]

I'm not sure that it is quite that clear-cut - if you are vaguely seal-shaped, and furthermore not moving with the speed and agility of a healthy seal, you might push a big shark's 'looks like food' button.

Staying together in a big, tight group might have been key.