THE EFFECTS OF SEX AND GONADECTOMY ON A SPATIAL NAVIGATION TASK IN DOGS

Sex differences in spatial cognition have been demonstrated in many mammal species, but not widely studied in dogs. Sixty-four pet dogs divided in four equally sized groups (intact males, orchiectomized males, intact females, ovariectomized females) were tested in a T-maze task consisting of three stages. In the first learning test, dogs had to learn which of the two arms led out of the maze. After 2 weeks, memory was assessed. In the last, reversal-learning test, the correct exit arm was inverted compared to the learning test. The whole task was successfully completed by 81.3% of intact and 56.3% ovariectomized females, 62.5% of intact and 50% of orchiectomized males. Intact females made fewer errors than intact males in the learning and memory tests (adjusted P<0.05, t-test) and chose with a lower latency in trials of the reversal-learning test (adjusted P<0.05, GLMM). The effect of gonadectomy was separately assessed within each sex. Intact females made fewer errors in learning and memory tests (adjusted P<0.05) and chose with a lower latency in trials of the reversal-learning test (adjusted P<0.05) than ovariectomized females. Intact males showed higher latency than orchiectomized males in reversal-learning test (P<0.05). Results show clear sex-related differences in spatial cognition. Gonadectomy mainly affected females, inducing a general worsening of performance in ovariectomized subjects. Findings underline the role of sex on spatial cognition in dogs, which may be relevant for specific training where good navigation skills are required. Results also raise questions about the possible consequences of gonadectomy on dog’s cognitive abilities.