Object play occurs in diverse animals in addition to birds and mammals. Although many carnivores engage in object play in a predatory context, many non-predators do so also. Conjectures over the years on the motivation to play are reviewed dealing with intrinsic, developmental, and stimulus factors. We then report on quantitative studies of the play of puppies from 6 litters (3 breeds) when given 5 different toys with different sensory and functional properties at half week intervals from 3 to 7 weeks of age. The propensity to engage with objects begins early, play complexity increases rapidly, the structure of the play is similar to adult object play, and breed differences were found. Object play with predatory characteristics appears before weaning, suggesting that hunger is not the primary motivation. Studying the development of object play in different dog breeds may be useful in addressing questions of domestication and play evolution.

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.

Studies exploring the development of object play of wolf pups are lacking. Comparisons of wolves vs. dogs can aid in teasing out the influences of domestication on any differences uncovered between wolves and various dog breeds. We investigated the development of object play from 2 to 9 weeks of age (14–63 days) in 2 litters of hand-reared wolf pups (Canis lupus). Both litters of pups were video-recorded in their home enclosures at week and mid-week timepoints. Each litter was given a separate set of the same five commercial dog (Canis lupus familiaris) toys with differing sensory and functional qualities. The first 10 min of activity from each session were analyzed using the Noldus Observer XT program and a previously developed ethogram of object related behaviors. The results were analyzed using repeated measures LMMs. Percent of time spent playing with toys, behavioral counts and behavioral diversity all increased significantly with age for wolf pups, and they were generally developmentally ahead of dog puppies. Wolves, like dogs, had preferences for some toys. These findings expand our grasp of infant wolf behavior, the comparative development of object play in canines, and provide a model for the study of domestication on play behavior.