Play alone proves little. A dog may chase several companions, yet repeatedly return to one when alternatives are available, suggesting that the attraction concerns the partner rather than merely the game. Choice carries more weight. In animal behavior, partner preference offers a way to distinguish broad sociability from a selective relationship.
Repetition needs careful interpretation. Two dogs that meet frequently may play together because their routines overlap, while matching size, energy or play style can make an encounter easier without establishing a deeper attachment. Availability can mimic affection. A stronger case would involve consistent choices across encounters, especially when the dogs also seek proximity or show affiliative behavior outside play, such as resting together or exchanging gentle contact. Context changes the reading. Not every recurring chase deserves the label of friendship, and no single gesture can establish what the relationship means to either animal when the game has stopped.
Friendship is a hypothesis. The useful question is whether a dog's preference persists beyond the conditions that first brought the pair together, rather than whether their romping resembles a human bond. Owners can watch quietly. Offering safe opportunities to choose, without forcing contact or overlooking signs of discomfort, can reveal whether a familiar companion attracts attention even when other playmates are present. Preference need not mean exclusivity. A dog can enjoy a wide circle while favoring particular partners, just as selective social bonds need not exclude sociability with others. The chase ends; the revealing moment may be which companion the dog settles beside.
