Tuesday, May 5, 2009

Why is This Alligator Smiling?

Perhaps the poet Tennyson said it best - In the spring, a young man’s fancy lightly turns to thoughts of love. And love is certainly in the air at Gatorland. (Gatorland is on Hwy 441, on the border of Orlando/Kissimmee- see the link below for full information.) When I came to Orlando in the 1960's, Gatorland was a little tourist attraction at the side of the road. Now it is a 110-acre theme park and nature conservatory and, according to its literature, is known as the Alligator Capital of the World.

Jim, Matt, Charlie, and Vince Lamb have each trekked over to Gatorland this Spring, and each came back with some fabulous photos. Not only are the alligators strutting their stuff, but the birds that make their home there are in full nuptial plumage. We'll write more about the birds in a future post, but today we're going to talk about the Alligator Water Dance.
This is so cool! In addition to his very audible bellow, as part of his routine to pick up attractive female gators, the male alligator generates an internal vibration, inaudible to humans ears, that sets off the water show you can see in Vince's photo above. Female alligators love this sort of thing, and off they go to the dance. If you follow the National Geographic link below, they have a cute (verging on cutesy) video about it.
This pre-mating ritual is fascinating in and of itself, but Vince noted that he was disappointed with his Alligator water dance photo because the nictitating eyelid displayed by the gator in his photo made the eye look dull. (Eyes are a big thing to photographers.)
According to Wikipedia, The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten the eye while also keeping visibility. There's a link to the full Wikipedia entry below - it's very interesting, and includes some very scholarly references. I was particularly interested in this sentence: Woodpeckers tighten their nictitating membrane a millisecond prior to their beak impacting the trunk of a tree in order to prevent their eyes from leaving their sockets. You gotta love Mother Nature's ability to plan ahead!
Frankly, I would not have noticed the duller eye if Vince had not pointed it out, but I've used a crop of one of Matt's water dance photos to show the difference.

Thanks to Vince and Matt for sharing their photos and their experience with us. Be sure to follow the link below to see more of Vince's work. (Matt's work can be seen in our Florida Beach Basics - The Space Coast DVD, which he also narrated, and in the accompanying reference cards.)


Florida Beach Basics said...

I got a nice email from Jay Wherley that he gave me permission to share. Follow the links to a couple of great photos that really illustrate the nictitating membrane.

I liked your info about the nictitating membrane - I had
caught one of the purple martins here with that membrane
covering the eye when feeding its young:

I also noticed it recently on a roseate spoonbill:http://www.pbase.com/wherley/image/111998757

Sandcastle Momma said...

That's fascinating. I've seen a lot of gators but had no idea about the vibration. You really do learn something every day!

iFlorida said...

Great picture! That's why i love Florida, because it has both amazing beaches and great wildlife!