Drop-in guests are no strangers to gopher tortoises. Certain snakes and frogs are routine roommates for the threatened species once common in Florida. Gopher tortoises calling the University of North Florida campus home, however, are being visited by a critter the likes of which they have never seen.
Created by two students and their professors, a subterranean robot camera mounted on miniature caterpillar tracks offers researchers a real-time view of the burrow's occupants.
"It's relatively noninvasive. It doesn't destroy the burrow or harm the tortoise or any other animal that may be in there," said Alexandra Legeza, a senior and biology major who partnered with Kevin Nguyen, an engineering major, to develop the maneuverable robot.
Operated remotely with a modified video game controller, the robot is about the size of a paperback book. High definition cameras at the front and back of the low-slung, all-terrain robot are encased in resilient clear plastic. The cameras beam a live video feed back to Legeza's laptop, which records the images.
"It's quick, easy and not limited by season, as bucket trapping is," Legeza said.
In the past, researchers and land managers typically used methods prone to inaccurate population assessments to estimate the tortoise populations. They would count the burrows then use a formula to calculate the population. Because tortoises often share burrows or use multiple burrows, that method resulted in overestimates, said Joe Butler, a herpetologist and UNF biology professor who has been studying the animals for about 20 years.
Trapping the tortoises in buckets or excavating burrows — which is detrimental to the animals — were the other methods routinely used, Butler said.
Gopher tortoises are a keystone species, Butler said, so it's important to have accurate numbers.
"So many other species depend on the gopher tortoise and its burrow," Butler said. "They dig up nutrients in the soil with their burrows, they'll eat seeds and deposit them as they move from place to place, and other animals, such as the Indigo snake and gopher frog, share their burrows."
Knowing the population and where it's located also is important because their available habitat has decreased at least 80 percent in the past century, he said.
Legeza is assisting Butler in his research. Nguyen, who recently graduated, was a student of UNF electrical engineering professor Allen Harris. Funded by a $4,000 seed grant from UNF's Environmental Center, the research robot is a joint project of professors Legeza and Nguyen.
They have sent the robot trundling down about 50 of the preserve's more than 400 tortoise burrows. The few tortoises they have encountered have appeared puzzled by the research robot.
"They generally don't do anything. They just look at it. Some will head bob at it," Legeza said.
One tortoise, however, tried to bite the camera when Legeza accidentally bopped the animal's nose while trying to dislodge the robot, which was snagged on a root. Neither tortoise nor robot was harmed.
They are seeking a patent for the device, which Nguyen designed and built. Although robots often are used to explore areas too dangerous or inaccessible to people, the research robot has advantages, Legeza said.
"It's about one-fifth the cost of other robot cameras. It's very adaptable. It's lightweight, easy to carry in a backpack and has the live feed," she said.
Legeza said the robot cost about $350 to build, not including labor. Similar robots cost from $5,000 to $15,000.
"Our robot is different because it's more affordable than the others out there. It would be more available to researchers and universities, which can have budget constraints," she said.
The robot is about 9 by 6 by 3 inches, but they are developing an even smaller one, Legeza said.
"The value goes beyond being able to see if a tortoise is down there. It also would be able to evaluate accurately all the species down there," Butler said.