Magnetic compass: A useful tool underground

Abstract

Living aboveground offers animals diverse cues for spatial orientation, but the underground picture is less colourful: besides darkness, subterranean rodents face restriction in useful orientation cues such as odors or sounds (Burda et al. 1990a). Target and landmarks are not directly perceivable and, as a consequence, distant orientation is heavily impeded. Subterranean mammals need to solve several major tasks relevant to spatial orientation. 1) They have to orientate quickly and efficiently in their dynamically changing three-dimensional burrowsystem, in order to frequent nest, food chambers, latrines, and harvesting grounds. 2) They must keep the course when digging longer foraging and dispersing tunnels. Straight tunnelling conserves energy because the animals do not search in the same area twice. 3) They need to restore and interconnect damaged burrows, effectively bypass obstacles, etc. 4) Animals temporarily leaving their burrows while foraging or searching for mates aboveground need to find their way back home.