Play like me: Similarity in playfulness promotes social play.

Social play is associated with the experience of positive emotions in higher vertebrates and may be used as a measure of animal welfare. Altering motivation to play (e.g.

Context-dependent individual differences in playfulness in male rats.

Play has been proposed as an indicator of positive emotions and welfare in higher vertebrates. This study investigated playfulness in male rats by exploring its consistency across motivational states (with/without prior short social isolation) and two age points at early and late adolescence. Twenty-four male Lister Hooded rats housed in cages of four underwent two play tests: conspecific Play-in-Pairs and Tickling by the experimenter, which were compared with play in the home cage and basal anxiety levels.

Facial Indicators of Positive Emotions in Rats.

Until recently, research in animal welfare science has mainly focused on negative experiences like pain and suffering, often neglecting the importance of assessing and promoting positive experiences. In rodents, specific facial expressions have been found to occur in situations thought to induce negatively valenced emotional states (e.g.

Cross-modal recognition of human individuals in domestic horses (Equus caballus).

This study has shown that domestic horses are capable of cross-modal recognition of familiar humans. It was demonstrated that horses are able to discriminate between the voices of a familiar and an unfamiliar human without seeing or smelling them at the same moment. Conversely, they were able to discriminate the same persons when only exposed to their visual and olfactory cues, without being stimulated by their voices.