Pack power

摘要

Like people, wolves have found that there are benefits to be had living in a group. Together they can more effectively take down large prey, raise families and defend their territory. The received wisdom is that there are also costs to group living, not least a greater risk of death from catching a contagious disease. Now a team of ecologists working in Yellowstone National Park in Wyoming have found evidence that for wolves, at least, that is not always the case. Wolves were driven to extinction by hunting in the Yellowstone region in the early 20th century, but were reintroduced in 1995 and have been closely monitored ever since by the National Park Service. This includes tranquillising 25 or so wolves a year and fitting them with radio collars so they can be tracked. Among the wealth of information this effort has produced, in 2007 researchers were alerted to a conta-gious illness creeping into the population.