Vive the vole!

April 1, 2008
The Vole Stays in the Picture
A northern redbacked vole from the study's field site in Alaska. Credit: Greg Dart, Alaska Star News

The gathering of data for research involving an animal usually involves invasive procedures or death for the experimental animals. But critical data may now be collected through a nonlethal procedure, according to a new paper for the forthcoming issue of Physiological and Biochemical Zoology.

In the paper “Dual-Energy X-Ray Absorbtiometry (DXA) Can Accurately and Non-Destructively Measure the Body Composition of Small, Free-Living Rodents,” Kalb Stevenson and Dr. Ian G. van Tets reveal that they have discovered that they can take a wide range of measurements accurately with a portable DXA device.

These body composition measurements in small rodents—water, protein, minerals, lean, and fat—are critical for dietary and environmental research. Previous measurements taken in the field, though not lethal, relied on length and body mass calculations, which are often inaccurate; methods used on laboratory animals are often lethal, precluding longitudinal research. Differing methods used in fieldwork and in the laboratory limited scientific collaboration. Legal and/or ethical barriers against invasive research on endangered species further hampered crucial studies. “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” said Dr. van Tets “so we decided to test whether DXA analysis could solve this problem”.

In their NSF-funded study of the northern redbacked vole (Clethrionomys rutilus), Stevenson and van Tets took a broad set of measurements accurately by employing DXA, using X-rays and mathematical formulas to noninvasively measure body content. Even transponder tags used to track the rodents in the wild did not interfere with their measurement of fat mass, lean mass, bone mineral content, bone mineral density, and fat-free mass.

“DXA worked better than we expected” Stevenson said “The measurements were consistent with those obtained via chemical (proximate) 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.”

Portable DXA devices provide the opportunity for quick measurements in the field and the ability to take measurements over time, allowing researchers to account for environmental factors. And, finally, field researchers and laboratory researchers will be able to collaborate using comparable data, allowing an increased degree of scientific rigor in comparative physiological studies.

Source: University of Chicago

Explore further: Sizing up the competition: Researchers compare body composition measurement techniques

Related Stories

Size zero is bad news for bones

January 5, 2010

( -- New research from the Children of the 90s project suggests that teenage girls who are too thin may be putting their bones at risk.

Recommended for you

Internet giants race to faster mobile news apps

October 4, 2015

US tech giants are turning to the news in their competition for mobile users, developing new, faster ways to deliver content, but the benefits for struggling media outlets remain unclear.

The dark side of Nobel prizewinning research

October 4, 2015

Think of the Nobel prizes and you think of groundbreaking research bettering mankind, but the awards have also honoured some quite unhumanitarian inventions such as chemical weapons, DDT and lobotomies.

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.