Spatial learning and memory in the blind mole-rat in comparison with the laboratory rat and Levant vole

Studies dealing with spatial orientation in mammals have mostly dealt with surface-dwelling species. We studied the ability of a subterranean rodent t o orient in space and compared it with two species of rodents that spend mo st of their lives above ground. The solitary blind mole-rat, Spalax ehrenbe rgi, inhabits an extensive, branching tunnel system that it digs itself and in which it spends its entire life. We examined its ability to learn and r emember a winding path towards a goal in a multiple labyrinth and compared it with Levant voles, Microtus guentheri, and laboratory rats, Rattus norve gicus. The mole-rats learned significantly faster than the rats and voles. Furthermore, their ability to remember the maze was significantly better th an that of the rats after 2, 7, 30 and 60 days from the end of the learning experiment and significantly better than the voles after 120 days. The mol e-rats still retained ca. 45% of their optimal performance at the end of th e learning experiment after 4 months compared with 20% for the voles after 4 months and less than 20% for the rats after 2 months. Despite having lost its vision, the mole-rat was thus more able to orient in a complex maze th an the surface-dwelling vole and laboratory rat. We-suggest that the mole-r at compensates for the sensory limitations imposed by the subterranean nich e and for its loss of vision by relying on the Earth's magnetic field and i nternal cues to steer its course efficiently. We discuss the possible mecha nisms of orientation. (C) 2001 The Association for the Study of Animal Beha viour.