Spontaneous directional preference in a subterranean rodent, the blind mole-rat, Spalax ehrenbergi

When released in a circular arena, blind mole-rats, Spalax ehrenbergi (karyotype 2n=60), from Israel displayed a significant preference for nesting at 72°and for building food caches at 37°, whereas the positions of latrines were not significantly different from a random distribution. The food cache and nest positions were related to each other. There were significant differences in scatter between both sexes in nest and in food cache directions which may reflect sex-dependent differences in the structure of burrow systems as known from the field. The exhibited preference and motivation for nesting appeared not to be affected by the season of the year. We suggest that the spontaneous preference for a certain direction may provide an animal with a reference point in a monotonous dark environment deprived of sensory cues. A possibility that the directional preference in the blind mole-rat may be related to magnetic compass orientation, as known in the Zambian common mole-rat (Cryptomys anselli), also a subterranean rodent, is discussed.