Ageing the beaver (Castor fiber L.): A skeletal development and life history calendar based on epiphyseal fusion

The skeletal development of 51 recent beavers (Castor fiber L.) from Sweden has been studied, with the purpose to put forward a method for ageing individuals from this species. The study of the epiphyseal fusion in 45 epiphyses allowed for the establishment of a calendar. The results indicate that the skeletal maturation of the beaver occurs as late as 12 years. It is suggested that such prolonged epiphyseal fusion is due to the aquatic mode of life of the beaver. The skeletal development additionally allows for the creation of five skeletally defined cohorts namely: juveniles, subadults, young adults, middle aged adults and old adults. It is suggested that this system be used when ageing skeletal remains of beaver from zooarchaeological assemblages and in wildlife management studies