Sharks

Nurse Shark Society

posted: 04/11/12
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Nurse Shark Society
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Nurse sharks are social creatures, a bit of an oddity among sharks. Sometimes 40 of them will pile together during their daytime snooze, even lying around on top of one another. They're also passionate about where they'll rest, visiting favorite spots again and again.

But at night, it's time to dine, and nurse sharks engage their powerful pharynx muscles to suck up prey before it knows what hit it. Lots of fish and crustaceans are on the menu, but these audacious (if somewhat lazy) sharks will even go so far as to flip over heavy conch shells so they can snack on what's inside. Snails don't stand a chance against this level of pharyngeal force.

And that's not all nurse sharks use their pectoral (front) fins for. Although nurse sharks do swim, they also use these fins to amble along the ocean floor. When a female isn't in the mood to tango, she'll sometimes find a sandy spot and dig down with her pectoral fins, making it harder for the male to make his move. Nurse sharks also have an exceptionally long caudal (tail) fin — it can account for about a quarter of their body length.

Nurse sharks range in color from yellow-tan to dark brown, and when they're young, they can change their skin color. If a tank full of juveniles is partially covered for a few minutes, the sharks in the shade turn lighter in color than the ones that are still lapping up sunshine.

If you want to see some of these social sharks, you my not have to travel far. They're easy to take care of in captivity, which makes them a popular aquarium attraction.

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