The development of object play in wolf puppies (Canis lupus)

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.