Seasonal variations of the digestive tract of the Eurasian beaver Castor fiber
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Forage availability for wild rodents varies with season. In turn, the composition of food can affect morphometric parameters of the digestive tract. This study was performed in Eurasian beavers (Castor fiber) whose population was close to extinction in most Eurasian countries, but has now increased. Due to the previous low number of studies, information about the effect of forage availability on the digestive tract morphology has previously been lacking. This study was performed using beavers captured from the natural environment during three seasons of different forage availability: winter, summer and autumn. It was found that the diet of the beaver varied during the year; in winter it was dominated by woody material consisting of willow shoots, whereas in summer the diet was primarily herbs, grass and leaves. Season also affected the mass of digested contents of the digestive tract. The digestive content increased in the caecum and colon in winter and autumn, when poor-quality food dominated the beaver’s diet. The results indicated that the digestive tract parameters of beavers varied based on the composition of available forage.
KeywordsDigestive tract Season Beaver Food preferences
The authors are grateful to Jan Goździewski from the Polish Hunting Association in Suwałki for capturing and delivery of animals.
This study was supported by a grant from the National Science Centre, grant No. NN 311 510139.
Compliance with ethical standards
The animals were captured with the approval of the Regional Directorate of Environmental Protection in Olsztyn, Poland (ministerial approval: RDOS-28-OOP-6631-0007-638/09/10/pj), and the experiments were performed in accordance with the standards of the III Local Ethical Commission for Experiments on Animals at Warsaw University of Life Sciences-SGGW (Permit number 11/2010).
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