Monday, January 3, 2011

Why every family should include at least one marine biologist

My nephew Adam is getting his PhD in Marine Biology. A few years ago he took me way out into the Everglades to catch and tag a few alligators. It was a blast.

Adam is a very handy resource when it comes to important marine biology topics. Note this recent email exchange:

Hey, Marine Biologist -

CSI Miami's latest episode opens with a guy on his cellphone stepping into his swimming pool, not noticing that there's an alligator in the pool. Which, of course, proceeds to attack him, making for a nice bloody dramatic beginning. Questions for you:

1. Would the alligator survive the chlorine?

2. Would an alligator in a pool automatically go after a human? If not, what would make an alligator attack someone in a swimming pool? (Not a super-big alligator, either.)

Just wondering. I know everything on TV is true (especially on CSI: Miami)...

- Your favorite auntie

* * * * *

Hey Auntie E,

Yes, an alligator could survive in a chlorine treated pool, but not for a really long time (like months). Gators can survive being exposed to almost anything for short periods of time (days - weeks) as long as they keep their mouth closed because their oral cavity is pretty much the only part of their body that contains highly permeable surfaces and therefore is the site for most ion exchange with their environment (i.e. chlorine, salt, etc.). If they don't open their mouths, they don't get exposed and it's all good in gator land.

An alligator would not automatically attack a human in a pool. Depends on the size of the gator and the size of the human. Alligators generally don't go after prey that are bigger than they are, though there are exceptions to the rule (e.g., deer). What would happen in the pool, I think, is that the gator would sense a human entering the pool through the vibrations on the water surface caused by their entry (they sense these vibrations with their "dome pressure receptors" located on their mouth), and also by the noise of course. The alligator would come over the the human to check it out and inspect the situation, and then it would decide to attack or not attack based on the human's size relative to it and its own hunger level. Gators also like the element of surprise, so if the human saw the gator and started trying to hit it or punch it in the mouth or something like that then the gator might decide that attacking wouldn't be worth it. If the gator on the show was small (less than 6 ft. or so) and the human was a big adult then I think most likely the gator would not attack, at least not immediately.

glad my PhD learnin' is proving to be useful in many contexts