A Descriptive Methodology for Studying the Ontogeny of Object Play and Breed Differences in Dogs (Canis lupus familiaris)

SIMPLE SUMMARY: The development of object play in animals, including dogs, has been understudied compared to social play behavior. The aims of the present study are to describe the development of a detailed ethogram of object play for dogs that can also be applied to studies of related canids. Moreover, we describe the ontogeny (i.e., the development) of object play in three breeds of domestic dogs from 3–7 weeks of age as they interacted with five different pet toys (objects). Individual behaviors were then categorized into three groups as follows: those that occurred only in the solitary context; those that occurred only in the social context; and those that occurred in both contexts. Theses behavior groups were analyzed for differences across breed and age. Solitary object play developed first, and social object play developed later across breeds. Uncovering early developing breed differences in object play behaviors may aid in understanding both how play develops and the role that selection and domestication has played in the evolution of dogs and their behavioral variability. ABSTRACT: Play behavior is a prominent aspect of juvenile behavior for many animals, yet early development, especially play with objects, has received little attention. Our previous study on object play introduced our general methods, focusing on litter differences in the developmental trajectory of object play and toy preferences. Here, we present a detailed ethogram of more than 30 observed object play behaviors. We focus on breed differences in the development of play in the three following breeds: Welsh Terriers, Vizslas, and standard Poodles. Puppies were video recorded from 3 to 7 weeks of age at half-week intervals upon the introduction of a standard set of five toys into their home environments. Ten minutes of video from each session for each puppy were analyzed using the Noldus Observer XT program. Aside from analyzing individual behaviors, they were also grouped into three behavioral categories. These were behaviors that occurred only in a solitary context, only in a social context, or in both contexts. Solitary object play developed first, and social object play developed later across breeds. There was a significant three-way interaction between breed, developmental age, and the context in which play occurred. Pairwise comparisons within each breed, age, and context are discussed, but a prominent result is that the onset of many behaviors occurred later in Welsh Terriers compared to the other breeds.