Tokumaru, R. S., Ades, C., Monticelli, P. F. 2015. Social support does not require attachment: Any conspecific tranquilizes isolated guinea-pig pups. Applied Animal Behaviour Science 171, 197-203.

Guinea pig pups produce typical distress whistles when isolated. Whistles’ frequency is decreased or abolished when they contact with the mother and, to a lesser degree, a sibling or even an unfamiliar female, is regained. Those non-aggressive companions were considered social support providers for reducing pup physiological stress responses and whistling rate in an unfamiliar environment. However, what would happen if the isolated pup would be in contact with an adult male, normally indifferent to pups, in such distress situation? The role of attachment and familiarity to males in promoting changes in distress responses of isolated pups was verified. Tests consisted of separating three week old pups from their family, in a familiar or an unfamiliar environment, and introducing a conspecific in the cage after one minute (mother, sibling, father or a strange male). Whistling and other behaviors were compared between the alone period and the accompanied period. Main factors were prior presence/absence of father (pups were raised with father until testing or only for the first week after birth), sex of pup, novelty of test environment and companion. It was verified that (1) all conspecifics reduced whistling rate (F4,88 = 77.89, p < 0.001), but pups behaved differently with different conspecifics; (2) suppression of isolation induced behavior did not necessarily occur because of previous attachment (e.g., pups in the PAF condition spent more time pausing, F1,22 = 7.68, p < 0.05, less time in passive contact with companions, F1,22 = 10.63, p < 0.01, and ate/drank less, F1,22 = 6.18, p < 0.05). It was concluded that the suppression of pup's isolation induced behavior by companions must not be used alone as a measure of attachment. It must be seen in an evolutionary perspective where the presence of any conspecific represents security offering self-protective behavior cues as finding a place to hide, and providing dilution effect against predation.

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