Gopher Tortoise—David Rostal
The aptly named Gopher tortoise is a master of the underworld, creating and
inhabiting elaborate burrows—some up to 30 feet in length. The herbivorous
tortoise, which is found in the American south-east, has fascinated David
Rostal of Georgia Southern University for 10 years.
NOVA: What's the greatest challenge about studying Gopher Tortoises?
David Rostal with an alligator snapping turtle
DR: Finding them above ground. They probably spend 60-70% of their time
underground. You can trap them at the mouth of the burrow, because they do
come out to eat every couple of days, but it's extremely time consuming.
Getting any real population data on them was tough.
NOVA: Tell me about the technology you now use to study Gopher Tortoises in
DR: Well, we call it a "Burrow Cam." The unit that we have is made by a
gentleman named Ed Wester. It's basically an infrared video camera system
mounted on the end of a telescoping tube that we can run down inside the
burrow. Around the lens is a series of infrared lights and we have a video
monitor that stays above ground. Our particular system cost about $1000. The
telescoping tube has to make a lot twists and turns in order to reach the back
of the burrow, where hopefully we find a tortoise.
NOVA: Can the tortoises see the infrared light?
DR: Yeah, they can to a degree. They will notice it and respond to it.
NOVA: Do they ever snap at it?
DR: No, no. These are extremely gentle animals.
NOVA: What has the "Burrow Cam" enabled you to discover about the Gopher
Tortoise that you otherwise would have missed?
DR: Our primary use of the "Burrow Cam" has been to evaluate tortoise
population numbers and to identify symbiotic relationships with other animals.
We're pretty sure we've had about an 80% decline in the tortoise population
over the last 100 years due to habitat loss. Georgia is probably the last
stronghold for them in the world. And there's literature, mostly from Florida,
showing that about 80 vertebrate species and over 200 invertebrate species
depend on these burrow systems for shelter. In Georgia, we're particularly
interested in the indigo snake, which utilizes these burrows during the winter
months. The "Burrow Cam" has allowed us to learn in a day what used to take a
month or more.
Photos: (1) Doug Jones; (2) David Rostal.
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