Open-field behavior in guinea pigs: Developmental and adaptive considerations

Two experiments were conducted with guinea pigs to test implications of a model which holds that social reinstatement tendencies and attempts to evade predation are the primary factors influencing how organisms initially react when placed in an open field. Because of the age-related reduction in need for maternal care, vocalization and ambulation latencies increased with age, and in support of the hypothesis that humans are perceived as predators, subjects tested in the presence of a human observer were less likely to move or vocalize than those tested alone. The data on vocalization latencies strongly suggest that the species- specific "whistle" of guinea pigs is a functional mammalian analog to the so-called "distress call" of domestic fowl.