You can take rats out of the wild for laboratory research, but it seems you can't take the wild out of the rats quite as easily.
That's what's revealed in The Laboratory Rat: A Natural History, an award-winning documentary written and produced by Dr. Manuel Berdoy of Oxford University. The film depicts how quickly lab rats return to their wild ways when given the opportunity to act out natural behaviors outdoors.
Berdoy, a zoologist in Oxford's department of veterinary services, released 50 rats into a large outdoor enclosure and followed their activities for six months. All of the rats were born and raised in laboratories and were the product of hundreds of generations of domestication. Like most laboratory rats, they had been selectively bred to be docile and easily kept in captivity.
The experiment, Berdoy explains, reveals "the range of behaviours and needs which, despite generations of domestication, remain innate and ready to be expressed when given the opportunity." Originally produced as a teaching tool for researchers, the film gives insight into the complex nature of one of the most commonly-used laboratory animals.
So what happens when a lab rat is suddenly freed from its life as a confined research subject into the untamed outdoors?
Curiosity, the first trait the animals exhibited, prompted them to investigate and test their new environment—and each other. In captivity, Berdoy's rats were housed in single-sex groups. So one of the first things the males did upon being released was check out their female counterparts.
In a matter of days, Berdoy observed, the rats had explored their new environment and located shelter, food, and water, despite having been fed a laboratory diet for their entire lives. They began forming hierarchical social relationships. And the females quickly began preparing for pregnancy by foraging and storing food.
The former lab animals also began to move like wild rats, leaping and jumping instead of shuffling around. Other natural behaviors the filmmaker documented included avoiding predators, selecting habitat, mating, giving birth, and even committing infanticide.
Despite Berdoy's shoestring budget and inexperience as a filmmaker, the documentary received an award for best nonbroadcast film at the Jackson Hole Wildlife Film Festival and the The Parthenon Entertainment Newcomer Award at the 2003 Living Europe film festival. The film is also slated to receive International Wildlife Film Festival awards for Best Government Agency film and Best Non Broadcast Program in May, in addition to several merit awards.
"It is tempting for lab workers to assume that domesticated animals like rats have long ago shed their capacity for natural behavior and activity and that they now are perfectly content to spend their lives in the small, barren cages that are typical of a laboratory setting," says Martin Stephens, vice president of Animals Research Issues at The HSUS. "Berdoy has demonstrated that lab rats certainly have not lost their innate behavior patterns."
More importantly, Stephens adds, Berdoy's findings "should prompt research laboratories and oversight agencies such as the USDA to revaluate what constitutes appropriate housing for these animals. Housing enrichments that benefit animal welfare are also likely to improve research results, given the widely accepted principle that good welfare is a prerequisite for good science."
To view clips from Berdoy's film, co-directed with cameraman Paul Stewart, visit the Rat Life website at www.ratlife.org.
Sources: Rat Life website; Living Europe Press Release; Nature, February 3, 2004 (www.nature.com/nsu/040202/040202-2.html)
