Some scientists suggest it could be still another sign of climate change: Salamanders in the Appalachian Mountains are getting smaller, they say, because in a drier, warmer climate, the little cold-blooded creatures use more energy to stay alive.
"As their temperature rises, all their physiological rates increase," said Michael Sears, a Clemson University biologist. "All else being equal, that means there is less energy for growth."
In a study earlier this year in the journal Global Change Biology, Sears and other researchers compared museum specimens of salamanders collected over a half century beginning in 1957 with those measured at the same sites in 2011 and 2012.
In all, they measured almost 9,500 adult salamanders and found their bodies were on average about 8 per cent smaller after 1980 than in the earlier decades.
The change was not universal. While in six species salamanders were smaller, there was no change in eight other species and salamanders in one species even increased in size. Samples were taken in Maryland, Virginia, West Virginia, North Carolina and Tennessee.
"We point to climate change as our best guess of what we think is going on," said Karen Lips, an associate professor in the University of Maryland's Department of Biology and a co-author of the paper.
So if salamanders are smaller what does it matter? It matters to the creatures throughout their forest habitat, Lips said.
"Because they are so abundant they are a food source for birds, snakes and small mammals, things like raccoons, possums and shrews," Lips said. If there are smaller salamanders "other animals will have to eat more, it will take them more time to find food and life becomes more difficult for everybody."
The study was also co-authored by Nicholas Caruso of the University of Alabama and Dean Adams of Iowa State University.
Noted ecologist and author Paul Ehrlich, a senior fellow at the Stanford Woods Institute for the Environment at Stanford University, said climate change might be the cause of smaller salamanders.
"The climate is changing more rapidly than we expected and that's a possible cause," said Ehrlich, who did not work on the study. "But there's a general loss of amphibians around the world with all kinds of reasons and all kinds of argument about it. Populations of amphibians are in bigger trouble than any other major group."