EN
This paper provides a criterion to determine the age of live Pyrenean desmans Galemys pyrenaicus (E. Geoffroy, 1811) by observing dental wear. The criterion is based on the comparison of the estimated age by examining the growth rings on dental sections and the wear observed on the upper canine tooth. Bone matter from different areas in the north of Spain was studied. This species has a high life expectancy. In its natural environment, the desman may live to be over 5 years old.