DEVELOPMENTAL-CHANGES IN THE SEQUENTIAL BEHAVIOR OF INTERACTING TIMBER WOLF PUPS

We used information statistics to quantify first-order sequential depe ndencies in the social behavior of two sibling wolf pups (Canis lupus) . Sequential dependencies in the behavior of the individual pups incre ased between the first sample (18-32 days of age) and two later sample s taken from 34-53 days and 64-106 days of age. Sequential dependencie s between pups were greatest during the second age sampled. We relate these findings to changes in the importance and style of interactions. In the first 32 days, social co-actions primarily involved mutual mou thing and pushing. Between 34 and 53 days, when interactions frequentl y became aggressive. pups were most responsive to the actions of their partner and tail-raising predicted biting. By 64 days, play-chasing w as the mode. By this age pups had formed a relationship, were less att entive to the specific actions of their partner, and biting was no lon ger predicted by tail-raising. These results illustrate the importance of considering demand characteristics in distinguishing capabilities from performance, and suggest that changing social organization may un derlie developmental changes in behavior. We also speculate that durin g these play-like interactions, pups may gain control over expressive displays. (C) 1997 Elsevier Science B.V.