Nor do scientists know how the disease is transmitted from one animal to another. Understanding how deer use the landscape may help answer that question, says Mathews, by providing insight into the movement and behaviors of animals in an area where the disease has gained a toehold.
Scientists have generally assumed that deer transmit the infectious prions among themselves through direct contact. One alternate hypothesis is that areas where deer congregate - mineral licks, for example - may become hotspots for the disease. In those areas deer frequently lick the soil. They leave behind saliva that may also contain prions. Whether that behavior and the consumption of contaminated soil is at all associated with transmission is speculative, Mathews emphasizes, "but we can't rule out deer congregating around hot spots as another means of transmission."
In their new study, what the Wisconsin scientists found to their surprise was that deer in south central Wisconsin use very small home ranges, about one-half square mile in size. These ranges tended to be smaller in areas with a higher amount of forest edge. It may be, she says, that deer in the area have an abundance of high quality resources - food, water, mates - and do not need to travel long distances to find those resources on the south central Wisconsin landscape. The study also shows that the size of deer home ranges was not related to the number of deer harvested or deer density.
In general, according to the study's results, females and adult males stay close to home. Young bucks travel on average five to seven miles from their home rang
Contact: Nancy Mathews
University of Wisconsin-Madison