Long Distance Guidance and Navigation in Bats

Abstract

The motivation for this master thesis was to investigate whether or not the Mexican fish-eating bat, Myotis vivesi, uses information from the earth's magnetic field for navigational purposes. Other possible navigational mechanisms are also discussed. How can this bat travel 30 km or more each night over large areas of sea, often in pitch dark conditions, and successfully find back to its roost? Experiments, where bats were manipulated with permanent magnets, were conducted on and around Isla Partida (Mexico) in June 2015. The report includes methods on how to properly calculate and determine the strength and size of the magnets used and data analysis between bats wearing magnets and bats used as controls. Simulation models of bat guidance and navigation are also presented. A large amount of GPS-tracks and weather data were available for analysis.\\\\It was found that this bat does not rely mainly on magnetic navigation or magnetic guidance. However, because of a small sample size of bats flying in overcast weather, one can not rule out the possibility that the bat is using magnetic information as a backup system for other navigational strategies.\\\\For further work, it is strongly recommended to look into the visual and olfactory capabilities of this bat.