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January 28, 2007

Will alligators get you?

Will alligators get you? Do they present a danger to divers? And why am I thinking about it? Well, in part because I had that experience at Catfish Sink at Manatee Springs State Park where we went in despite having spotted that alligator. The sink was relatively large and the gator wasn't close, but there were a few tense moments of decision making nonetheless. We did go in and down to the bottom of the sink at 65 feet, but the instructor kept an eye on the gator who never left the surface and didn't bother us when we ascended. The subject of the gator has come up a few times since, and we've been joking how the gator grows larger every time we tell the story or think back of it.

Well, I was reminded of that while reading the late Sheck Exley's book "Caverns Measureless to Man." In it Exley describes an excursion into a sink with an alligator. The sink's surface was considerably smaller than Catfish Sink, perhaps 80 feet diameter, and Exley describes the 8-foot alligator as staring at them arrogantly, as if conveying that he was the master of this place. He went on describing whether or not the five of them, one without any kind of wetsuit protection, should go in or not.

They decided they would, primarily based on Exley's unequivocal statement that crocodilians could not withstand pressures deeper than ten feet, and so they'd be safe from the gator below that. All went well during the dive, but Exley describes how they performed their usual ten-feet decompression stop at 15 feet instead, beyond the assumed reach of the alligator. After that they made a quick exit out of the sink. Exley added that in that year, back sometime in the 1970s, there had been seven reported alligator attacks on humans, several of them fatal. He also reported that the great majority of the attacks had been done by alligators who had been fed by humans, and thus lost their fear of them. As it turned out, the gator in that sink had, in fact, been fed by humans. Two older ladies regularly stopped by to feed "Ollie" marshmallows.

That made me think. I had previously been trying to find references on the web as to how deep alligators dive, but had found nothing. I view Exley as an expert in all things diving, and especially diving in Florida where there are a lot of gators, and so his authoritatively stated position carries weight. Still, as I plan on diving in Florida again I hoped to get some more information.

Eventually I came across a website named crocodilian.com, an Australian site run by one Dr. Adam Britton who appears to be one of the world's foremost experts on crocodilian behavior. The site provided a ton of valuable information, but, again, nothing on depth. Dr. Britton invited questions, and so I sent him this email:

Hi!

The late cave diving explorer and pioneer Sheck Exley stated in his book
"Caverns Measureless to Man" that crocodilians cannot handle pressure
below ten feet. So they decompressed deeper when alligators were
present.

How deep do crocodilians dive?

Conrad

I was pleasantly surprised to receive an email response from Dr. Britton within a day or so:

Hi Conrad,

There are reports from Lake Chamo in Ethiopia of crocodiles found below 60
feet, and I've had crocs on harpoon lines that sink to the bottom of tidal
rivers which are in excess of 10 feet deep, so Sheck Exley's statement
doesn't quite ring true. As to their maximum depth I really don't know, and
I am sure nobody else does either - virtually no work has been done in that
area, so we're relying on anecdotal observations. There are depth
monitoring devices that can be attached to transmitters, and when I get a
chance to use one I'll let you know!

Best wishes,

Adam

So there. In the light of this information, I wonder where Sheck got his information from. Obviously I can't ask him, and so we must assume that alligators can, and may, indeed dive deeper. This would be good information for divers to know. Attaching a depth monitoring device onto a crocodile or an alligator seems doable and I'd love to know the results of the data collected. As is, I'll probably judge any future alligator situations on a case-by-case basis. How many? How big? How close? Carol has been diving with gators present and says they always retreat when they see divers and I have no reason to doubt that. But knowledge backed by research is always a good thing. Oh, and for a fascination description of exploration of the Manatee Springs Cave System, click here.

Posted by conradb212 at January 28, 2007 11:06 PM

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