Behavioural Analysis of Two Rodent Species from Different Ecological Habitats

The systematics of the genus Mus over the Iberian Peninsula, as well as in the entire Mediterranean region,is as yet unclear. The species Mus spretus, Lataste (1883) and Mus musculus (with two sub-species refered to as M.m.brevirostris, Waterhouse (1837), the southern, and M.m.domesticus, Rutty (1772), the northern forms), have been noted in the Peninsula (1,2,3). The biochemical similarity of these two Mus musculus forms has led several authors (4,5,6) to conclude that they are equivalent. Here both morphotypes will be refered as M.m. brevirostris. Until recently, M.spretus was considered a subspecies of M.musculus (7) but, as it is sympatric with M.m.brevirostris in Iberia and the South of France, this contravenes the modern definition of a subspecies (8). Indeed, recent biochemical studies (3,4,9,10,) confirm that Mus spretus is clearly distinct from Mus musculus brevirostris. Based on biochemical data, Bonhomme and colleagues (9,11) claimed that there were four groups with genetic distances at species level in the genus Mus in Europe, with M.spretus and M.m.brevirostris/domesticus being two of them.