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Wednesday, March 28, 2012
The Pond from a Snapping Turtle’s Point of View
Lincoln Park Zoo biologists have been tracking painted turtles at Nature Boardwalk at Lincoln Park Zoo since September 2010. To do this, we use radio transmitters, which are small devices we attach to the carapaces (upper shells) of the turtles.
The transmitters send a signal that can be picked up using a receiver. The receiver is directional, meaning the turtle is located along the line where the signal is strongest. This study has given us an idea as to how painted turtles perceive the habitat at Nature Boardwalk. For example, we know that the painted turtles spend the winter around the edges of the island. (You can learn more about turtle tracking here.)
However, the painted turtles only tell part of the story; in addition to painted turtles, red-eared sliders, snapping turtles and a map turtle all make their home at the pond. So how do these other turtles use the habitat? We’re now one step closer to answering this question with the help of a snapping turtle at Nature Boardwalk.
The female snapping turtle at the top of the post weighs in at about 3 pounds. That might not sound like much, but even small snapping turtles have an extremely powerful bite (hence the name). The species is omnivorous, eating basically anything they can get a hold of, from aquatic vegetation to carrion to small animals, like ducklings.
While snapping turtle eggs and hatchlings have many predators, such as raccoons, once a snapping turtle reaches adulthood would-be predators leave them alone. (Large snapping turtle can be threatened by traffic when crossing roads to find good places to dig nests.)
Turtles at Nature Boardwalk are given PIT tags so they can be individually identified. A PIT tag is a tiny device, about the size of a grain of rice, that is inserted under the skin of an animal and can be scanned and read with an instrument similar to a barcode reader. If you have pets, you may be familiar with these as pets are often given PIT tags so they can be identified and returned to the owner if they get lost.
We radiographed this turtle to see if it had been caught before. As you can see, there was no PIT tag. The radiograph does show the transmitter that has been attached to the outside of the turtle’s shell. (The white line on the bottom is just the metal handle of the bucket the turtle was in.)
In her first few days with a transmitter, this snapping turtle has been exploring Nature Boardwalk. She has traveled from one side of the pond to the other. We’ll be watching this turtle’s movements and comparing them with those of the painted turtles we’ve been tracking. Stay tuned to hear more about what the pond looks like from the point of view of a snapping turtle!
Nature Boardwalk at Lincoln Park Zoo
By transforming the South Pond into Nature Boardwalk, Lincoln Park Zoo has created an urban ecosystem in the heart of the city. Enjoy a virtual view as native plants and animals establish themselves in this rare refuge.
As Lincoln Park Zoo’s director of horticulture, Brian oversees the zoo’s gardens, from bud to bloom.
As coordinator of wildlife management, Mason chronicles the bugs, birds, fish, insects, mammals and more that make their homes at Nature Boardwalk.
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