Mother bats: Experts at saving energy

HAMBURG, Germany, Feb. 10 (UPI) -- German scientists say they've discovered wild female bats' temperature regulation strategy is flexible, switching between two modes.

The researchers, led by Iris Pretzlaff of the University of Hamburg, found that in order to regulate their body temperature as efficiently as possible, wild female bats switch between two strategies depending on both the ambient temperature and their reproductive status.

Pretzlaff and her colleagues said they investigated, for the first time in the wild, the thermo-regulation strategies used by communally roosting Bechstein's bats during different periods of their reproductive cycle -- pre-lactation, lactation, and post-lactation.

The researchers found the bats' metabolic rate was strongly influenced by the ambient temperature. However, by roosting in groups, the bats were able to regulate their body temperature more effectively, despite changes in daily ambient temperature.

The scientists also determined the bats used torpor to minimize energy expenditure, particularly post-lactation -- more than twice as often than during the other two periods.

"We were able to demonstrate … the significance of behavioral and physiological flexibility for optimal thermo-regulatory behavior," the researchers wrote. "Our study also highlights the importance of field studies, where the animals can use their behavioral and physiological repertoire, which is often not possible under the generally more controlled regimes in laboratory studies."

The study appears in the online edition of the journal Naturwissenschaften -- The Science of Nature.