Interaction of separation distress with fear in infant dogs.

Forty-one Telomian, beagle, and F1 hybrid puppies were tested in the presence and absence of a sound-producing stimulus under 2 social conditions, single and paired, at 6, 7, and 8 weeks of age. The sound stimulus definitely produced fearful reactions, as measured by tail carriage, which were not affected by social condition and accompanying differences in distress vocalization. Nor was distress vocalization significantly altered by the sound stimulus. We conclude that sound-induced fear and separation distress are separate and independent affective states. Social condition and the presence of the sound stimulus produced interactive effects at the behavioral level in that paired animals showed longer latencies to contact and maintained greater distances from the sound stimulus.