Uphill locomotion in mole rats: a possible advantage of backward locomotion

Mole rats were videotaped while locomoting in a Plexiglas tube to evaluate the effects of inclination on locomotion. Animals moving uphill preferred to go backward using plantigrade foot postures, presumably to prevent sliding. Uphill backward locomotion also allowed animals to cope with changes in weight distribution between the hind and forelimbs without modifying footfall pattern relative to the direction of progression. When the animals did use uphill forward strides, they switched to asymmetrical gaits, which are associated with increased propulsive forces. These and prior results suggest that weight distribution and direction of progression can modify the natural pattern of stepping in mammalian quadrupeds.