Rodents move their eyes in opposite directions, thereby
always keeping an eye on the airspace above them
Scientists from the Max Planck Institute for Biological
Cybernetics in Tübingen, using miniaturised high-speed cameras and high-speed
behavioural tracking, discovered that rats move their eyes in opposite
directions in both the horizontal and the vertical plane when running around.
Each eye moves in a different direction, depending on the change in the
animal’s head position. An analysis of both eyes’ field of view found that the
eye movements exclude the possibility that rats fuse the visual information
into a single image like humans do. Instead, the eyes move in such a way that
enables the space above them to be permanently in view – presumably an
adaptation to help them deal with the major threat from predatory birds that
rodents face in their natural environment.