Are smelly toys more fun? Shelter dogs' preferences for toys, scents, and scented toys

Abstract

As dogs reside in shelters awaiting adoption, it is critical that they remain behaviorally healthy. A variety of enrichment strategies improve the welfare of shelter dogs, including object (usually in the form of toys) and scent enrichment. However, for these interventions to be enriching, dogs must engage with the items and their welfare be positively affected. Thus, by identifying dogs’ preferences, shelters can improve the function of their enrichment. Using a 15 min free operant preference assessment, an assessment in which the subject is given free access to a variety of items and the duration of their engagement with each item is recorded, we investigated 34 shelter dogs’ preferences for four different toys: a stuffed toy, tennis ball, Nylabone, and flying disc. We also investigated dog’ preferences for four scents: hotdog, peppermint, duck, and an unfamiliar dog. Finally, we applied the dog's preferred scent to their most and least preferred toys to investigate whether adding their preferred scent would increase the amount of time they engaged with those items compared to unscented duplicates. During the toy preference assessment, we observed that dogs, on average, only interacted with toys 3.35 % of the 15 min session. However, we found that dogs engaged over eight times longer with the stuffed toy as compared to all other toys, F (1, 134) = 64.40, p <.001. There was a marginal effect of type during the scent assessment, F (3, 132) = 2.50, p =.062, but post hoc comparisons were not significant. When we applied each dog's preferred scent to their most and least preferred toys, we found statistically significant main effects for preference, F (1, 132) = 54.95, p <.001, and scent, F (1, 132) = 7.16, p =.008, and a significant preference-by-scent interaction, F (1, 132) = 4.66, p =.033. The addition of scent increased engagement with both toys, such that dogs spent 4.2 and 13.7 times more seconds with their most and least preferred toys, respectively. In addition to our results aligning with prior research demonstrating that dogs prefer soft versus hard toys, these findings suggest that combining objects and scents can increase dogs’ engagement with enrichment and may be especially impactful when providing shelter dogs with less preferred objects, such as hard toys.