The effect of age, sex and gonadectomy on dogs' use of spatial navigation strategies

In this study we assessed the effect of sex and gonadectomy on the type of spatial strategy (allocentric or egocentric) preferentially used by dogs in the acquisition of a navigation task and their ability to resort to the non-preferred strategy. Fifty-six dogs were involved in the study, divided in four equally sized groups based on sex and gonadectomy. Dogs initially underwent a learning phase, where they entered a plus-shaped maze from one arm and had to learn the position of a food bowl, which was placed in one of the lateral arms. The task could be achieved by relying on an either egocentric (i.e. learning to turn left or right) or allocentric strategy (i.e. using the external cues provided within the maze as a reference the position of the baited bowl). Following training, dogs were let in the maze from the entrance opposite to the one used in the learning phase, so that use of an egocentric strategy would lead them to search for food in one arm, while using an allocentric strategy would lead them into the opposite arm. Dogs' choices were used to determine their preferred strategy. In the last training phase, we assessed dogs' ability to resort to their non-preferred strategy to find the baited food bowl, by removing external cues and placing the baited bowl always at the same side of the dog, for subjects deemed as allocentric, and by keeping external cues and placing the baited bowl in a constant location relative to the cues, for dogs deemed as egocentric. No effect of sex was found on strategy preference, but ovariectomized females were significantly more likely to prefer an egocentric strategy, implying a role of ovarian hormones in biasing navigation strategies. The probability of resorting to the non-preferred strategy increased with aging in females and decreased in males. The higher requirement to cope with unpredictable environments during dispersal may support a predisposition to flexibly use different sources of information in younger males. By contrast, experience may be needed by females to reach the same proficiency, thereby justifying the increase in flexibility with ageing. In addition to increasing our knowledge about navigation, these results highlight effects of sex and ovariectomy on dog cognition, with potentially important implications regarding the management of dogs in different fields.