After studying the creatures at the Toledo Zoo, Stephen Reilly, associate professor of biological sciences, and doctoral student Eric McElroy determined that they use both forms of locomotion, which are energy-saving mechanisms generally believed to be important only in fast-running animals such as mammals and birds.
The research was published in the March 8 issue of the journal Proceedings of the Royal Society B: Biological Sciences. Andrew Odum, curator of herpetology at the Toledo Zoo, and Valerie Hornyak, head herpetology keeper, were co-authors of the study.
Tuataras, which are usually about 1 to 2 feet long, look like large lizards with green or brown scales and short spikes on their backs. They have unique anatomical features that are somewhere between those of lizards and birds. The critters are found only in New Zealand, where the cool climate is ideal for these animals that can't survive in temperatures above 25 degrees Celsius (77 degrees Fahrenheit). The animals can grow as old as 100 years, and live mostly off of insects, eggs and small birds. Fossil records show that the tuatara lived on Earth as early as 225 million years ago and hasn't changed significantly over time.
"Tuataras are the oldest living models of early tetrapods (four-legged animals) still alive today; that's what makes them so interesting," Reilly said.
In the recent study, the tuataras and salamanders walked and ran on a trackway with an integrated plate that measured the force with which the animals hit the ground with each step. From videotapes and the force measurements, the researchers could tell when the animals were walking or running. The difference is not obvious in these critters, which tend to move with a slow, lumbering gait. T
Contact: Andrea Gibson