Urinary posture and motor laterality in dogs (Canis lupus familiaris) at two shelters

•Most studies of motor laterality in dogs have focused on staged forelimb tasks.•We examined instead the hindlimb raised when urinating during walks of shelter dogs.•Propensity to raise a hindlimb varied with sex and age, but not reproductive status.•We found no evidence of a population hindlimb bias and most dogs were ambilateral.•Use of a natural hindlimb behavior to assess laterality has benefits and costs. Motor laterality is the preference shown for using one limb or lateral half of the body over the other. In domestic dogs, most laterality studies have examined forelimb preferences during staged tasks. We focused instead on hindlimb preferences during urination when males use the raised-leg posture and females the squat-raise. We observed individual dogs during walks at two shelters (Tompkins County SPCA and Cortland Community SPCA) and recorded posture used for each urination and hindlimb raised, if any. First, we examined whether raising a hindlimb during urination varied with sex, age class, or reproductive status (females, anestrous intact or spayed; males, intact or neutered). Second, for dogs that raised a hindlimb during urination, we determined whether a population bias existed. Finally, for dogs with at least 10 urinations in which a hindlimb was raised, we examined whether a significant hindlimb preference existed. For some analyses, we had sufficient dogs at only one shelter. We found that males were more likely than females to raise a hindlimb during urination (P