As the climate gets warmer North American salamanders are forced to burn more energy; The changing world has caused the amphibians to shrink.
The salamanders are believed to be about eight percent smaller than they were in the 1980s, when researchers first started studying them, a Clemson University news release reported.
"One of the stresses that warmer climates will impose on many organisms is warmer body temperatures," Michael W. Sears of the biological sciences department. "These warmer body temperatures cause animals to burn more energy while performing their normal activities. All else being equal, this means that there is less energy for growth."
In order to discover how climate change affected these salamanders researchers created a virtual version of the creatures. They used this model to estimate how many calories a salamander grew while performing its daily activities.
The models showed salamanders today are just as active as they have been throughout history.
"Ectothermic organisms, such as salamanders, cannot produce their own body heat," Sears said. "Their metabolism speeds up as temperatures rise, causing a salamander to burn seven to eight percent more energy in order to maintain the same activity as their forebears."
The salamanders' changing size is one of the "largest and fastest rates of change" ever witnessed by scientists.
"We do not know if decreased body size is a genetic change or a sign that the animals are flexible enough to adjust to new conditions," Karen R. Lips, associate professor at the University of Maryland's (UMD) department of biology and co-author on the paper, said in the news release. "If these animals are adjusting, it gives us hope that some species are going to be able to keep up with climate change."
In the future the research team hopes to compare salamanders that are shrinking to those in other regions who are disappearing altogether in hopes of finding the root cause of these changes.