Studying Rodents Without Killing Them

The collection of important scientific data can sometimes be lethal for small animals in the field or the lab.

But thanks to Kalb Stevenson and Dr. Ian G. van Tets’ Dual-Energy X-Ray Absorbtiometry (DXA), scientists can now accurately and non-destructively measure the body composition of small, free-living rodents. The portable DXA device can quickly take a wide range of accurate measurements, including a rodent’s water, protein, mineral, lean and fat composition.

The data, critical for dietary and environmental research, previously relied on the often inaccurate practice of measuring length and body mass calculations in the field - or the killing of animals in the laboratory. "We needed a way to accurately and consistently measure the body condition of small mammals recaptured at different times of the year and could not do so using traditional means" van Tets said. "So we decided to test whether DXA analysis could solve this problem."

Aside from alleviating the legal and/or ethical barriers in place against invasive research on endangered species, the DXA also has the potential to increase collaboration in the scientific community by standardizing the differing methods used in fieldwork and in the laboratory.

In their study of the northern redbacked vole, Stevenson and van Tets successfully took a broad set of measurements accurately with the portable device. The "DXA worked better than we expected," Stevenson said. "The measurements were consistent with those obtained via chemical analysis and required nothing more than the machine itself, a laptop, and a power source. As subjects are not harmed, we can use this technology to track changes in individual animals over time and already have DXA-based projects underway studying the effects of season and/or hibernation on the body composition of animals as diverse as voles, ground squirrels, and black bears."

The work, detailed in the latest issue of the journal Physiological and Biochemical Zoology, was funded by the National Science Foundation.

 --LiveScience Staff

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