Short-term benefits of play behavior and conflict prevention in Pan paniscus

Most theories on the function of play have focused on ultimate rather than proximate benefits. Play peaks during juvenility but, in some species, it is present in adulthood as well. In primates, social play and grooming often show a matched pattern because they bring individuals into close contact and favor social cohesion. In Pan, researchers […]

Ear and tail postures as indicators of emotional valence in sheep

To date, most studies on animal emotions have focused on the assessment of negative emotional states, and there is a lack of approaches to characterising positive emotional states. The aim of this investigation was to measure differences in ear and tail postures in sheep exposed to situations likely to induce states of negative, intermediate and […]

Do pigs distinguish between situations of different emotional valences during anticipation?

An animal’s welfare is strongly affected by its emotional state. Thus, many recent studies have focused on measuring the emotional states and responses of animals. However, there is still a lack of knowledge on assessing positive emotions, although it is widely accepted that positive emotions are needed to ensure good welfare. In the present study, […]

Physiological expression of emotional reactions in sheep

With the aim of judging emotional valence from an animal’s perspective, multiple physiological variables were recorded in sheep when they were exposed to situations likely to induce negative and positive emotional states. Fourteen sheep were conditioned for several weeks to anticipate the delivery of standard feed. In three experimental trials carried out thereafter, the animals’ […]

Common toads (Bufo arenarum) learn to anticipate and avoid hypertonic saline solutions

Toads (Bufo arenarum) were exposed to pairings between immersion in a neutral saline solution (i.e., one that caused no significant variation in fluid balance), followed by immersion in a highly hypertonic saline solution (i.e., one that caused water loss). In Experiment 1, solutions were presented in a Pavlovian conditioning arrangement. A group receiving a single […]

Chimpanzee (Pan troglodytes) anticipation of food return: Coping with waiting time in an exchange task

Despite controversial expectations that animals achieve reciprocal altruism, it is unclear if nonhuman species possess the necessary cognitive abilities. For reciprocal altruism, individuals must anticipate the loss of a commodity and accept a delay before some return. The authors investigated the abilities of 5 chimpanzees (Pan troglodytes) to cope with increasing waiting duration in exchange […]

Anticipation of future events in squirrel monkeys (Saimiri sciureus) and rats (Rattus norvegicus): Tests of the Bischof-Kohler hypothesis

The Bischof-Kohler hypothesis holds that nonhuman animals cannot anticipate a future event and take appropriate action when that event involves satisfaction of a need not currently experienced. Tests of the Bischof-Kohler hypothesis were performed with squirrel monkeys (Saimiri sciureus) and rats (Rattus norvegicus). In experimental trials with both species, a nonthirsty animal had its water […]

Predictors of anticipatory cortisol reactivity to subsequent stressors

Understanding the nature, predictors, and consequences of anticipatory biological stress responses are important in understanding long-term effects of repeated stressors. We examined anticipatory cortisol responses after an individual has actually experienced and reacted to a stressor once and is anticipating a second similar stressor. We hypothesized that how an individual reacts to the first stressor […]