Scientist Hopes Camera Can Get Home Movies of Alligators

Greg Marshall wants an alligator’s eye view of its world, so he is working on a camera that alligators, or other types of large sea dwellers, can haul down into their world to give scientists an idea of how they live.

“We hardly know anything about many animals’ underwater behavior,” Marshall said. “Take sea turtles. We know what they do on the beaches when they nest. We have some ideas from incidental observations what they do in the nesting areas. But generally we don’t know what these animals actually do, how they interact with their environment.

“It’s very basic biology,” Marshall said.

Initiated Idea

He said he got the idea for the camcorder system while working in Central America and seeing sharks being escorted by ramora fish.

“I thought, ‘wouldn’t it be interesting to be dragged along by a shark all day, just to see what it does,’ ” he said. So he began assembling pieces for a system that can be attached to any animal larger than a juvenile sea turtle.

There is interest in his project from biologists studying a variety of animals, from alligators to Antarctic seals.

“I think there may be a possibility of applying this method to studying whales,” Marshall said.

His problem is taking off-the-shelf equipment, modifying it, then building a housing that will protect the camera from the tremendous water pressure encountered by deep-diving animals.

“What I’ve done is build a custom fiberglass housing, which I’ve tested to about 1,000 (pounds pressure per square inch), which is about 2,000 feet depth,” he said.

The other problem is timing.

The camcorder has a life of about two hours--the amount of tape in one cassette.

One idea is a mercury switch for cameras on sea turtles, which will leave the camera off until it dives, then switch on to record what the turtle does while it is on the bottom.

It may take several weeks to fill the cassette. He plans to develop a harness that will decay in that time, with the rig floating to the surface.

Radio Signal

Then a radio will send a signal to scientists to pick it up.

“It sees what the eye sees. If you have 6-foot visibility, that’s what it will see,” Marshall said. “In terms of visual impact, it would be much more interesting to be in nice clear waters, but in terms of biology, it really doesn’t matter.