In house mice (Mus domesticus), like in other mammals, individual recognition is essential to many aspects of social and reproductive behaviour. The major source of information about individual identity in rodents is urine, which contains a huge amount of proteinaceous chemosignals, i.e., the Major Urinary Proteins (MUPs). It has been suggested that such a considerable loss of protein (mainly in males in laboratory mice and in both sexes in wild mice) might imply potential highly selected biological functions. Recently, it has been shown that MUPs represent the major candidates for individual recognition in male mice, by conveying information about the ownership signature. Here I give a review of the biochemical and behavioural attempts to elucidate the structure, identity and the pheromonal functions of MUPs in house mice. Also, I discuss the potential mechanisms of MUP involvement in male-male, and in male-female social and reproductive interactions. No role of female MUPs on inter-female behavioural interactions has been postulated so far. I present here the results of a pilot experiment on female alliance formation in relation to individual MUP-profile sharing. Clearly, further studies are needed to elucidate the potential implication of MUP-mediating individual recognition in complex aspects of female mice sociobiology, such as the inter-female social preference development and communal breeding decision.
Keywords: pheromones, individual recognition, rodents, chemical communication, sociobiology