 The study examined the effects of high elevation living on the brains of rodents. The researchers found that the brains of rodents living at higher elevations were smaller than those of rodents living at lower elevations. They also found that the genetic component of this difference was stronger than the environmental component. This suggests that natural selection has acted to reduce brain size in rodents living at high elevations. This article was authored by a Lewinny-Nendavella, Catherine M. Ivey, Graham R. Scott, and others.