Comparative bite force in two syntopic murids (Rodentia) suggests lack of competition for food resources.

Closely related syntopic species have been shown to avoid competition by differentiating in the type of food they process. This can be achieved by changes in size or in the masticatory apparatus that produce modifications in bite force. The wood mouse (Apodemus sylvaticus L., 1758) and short-tailed mouse (Mus spretus Lataste, 1883) are two murid rodent species found in syntopy in the south of France. We measured bite force in wild specimens of both species to test for differences in performance. Despite its greater body mass, the wood mouse showed only slightly higher bite force than the short-tailed mouse. We found no clear sexual dimorphism in either species, however among the males of the short-tailed mouse, two groups appeared in terms of bite force. This bite force difference may correspond to a hierarchical organisation of these males. Overall, it seems that both species have similar bite forces and accordingly overlap in the resources they use. Other factors may exist that create a niche differenti...