The research program is a part of a larger study of the asymmetry in rodents. The goal is to detect the biological damege in free living rodents exposed to environmental pollution. Rodents populations of South Europe, belonging to species of subgenus Sylvaemus (Apodemus sylvaticus) are going to be examined. The research is based in the study of asymmetries and anomalies of teeth and palatal ridges. The dental maxillary profiles and palatal ridges of each animal will be faced with drawing tube on Wild microscope. The age will be determined using the method of the dental tubercles erosion. Frequencies of new and/or supplementary tubercles will be analyzed according to the species and population.

In other studies it was observed that wild rodents populations (Apodemus sylvaticus and A. flavicollis) show a high frequency of asymmetries and and anomalies of teeth and intermolar crests. A great number of supplementary tubercles was find in upper molars of Lucenian, Calabrian and Balkanian rodents populations, and this fact can be considered as primitive character. the presenceof a similar frequency of tubercles in Apodemus sylvaticus from Spain, will be studied to determine the extension of this primitive character.

The palatal ridges asymmetry in different populations of South Europe Apodemus might also be used as indicator of damage in the environment pollution monitoring.