Seasonal variations of the digestive tract of the Eurasian beaver Castor fiber
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).
- AOAC (2005) Association of Official Analytical Chemists Official Methods of Analysis. 18th edn., ArlingtonGoogle Scholar
- Baldizan A, Dixon RM, Parra R (1983) Digestion in the capybara (Hydrochoerus hydrochaeris). S Afr J Anim Sci 13:27–28Google Scholar
- Barreto GR, Quintana RD (2012) Foraging strategies and feeding habits of capybaras. In: Moreira J, Ferraz K., Herrera E, MacDonald D (eds) Capybara: biology, use and conservation of an exceptional neotropical species. Springer-Verlag New York Inc, pp 83–96. https://doi.org/10.1007/978-1-4614-4000-0_4
- Byanet O, Abayomi AO, Aondohemba TJ (2015) Comparative morphometric analysis of the gastrointestinal tract of the captive greater cane rat (Thryonomys swinderianus) and African giant pouched rat (Cricetomys gambianus). Ital J Anat Embryol 120:49–58. https://10.13128/IJAE-16474
- Central Statistical Office, Environment (2016) Statistical information and elaborations. Warsaw, p 154. http://stat.gov.pl/en/topics/agriculture-forestry/forestry/forestry-2016,1,7.html
- Gonzalez-Jimenez E, Parra R (1972) Estudios sobre el chigűire. Hydrochoerus hydrochaeris: 1. Peso de los diferentes organos y partes del cuerpo. Acta Client Venez 23(Supll.1):30Google Scholar
- Gruninger RJ, McAllister TA, Forster RJ (2016) Bacterial and archaeal diversity in the gastrointestinal tract of the North American Beaver (Castor canadensis). PLoS ONE 11:0156457. https://doi.org/10.1371/journal.pone.0156457
- Halley D, Rosell F, Saveljev A (2012) Population and distribution of Eurasian beaver (Castor fiber). Balt For 18:168–175Google Scholar
- Janiszewski P, Gugołek A, Łobanowska A (2006) Use of shoreline vegetation by the European beaver (Castor fiber L.) Acta Sci Pol Silv Colendar Rat Ind Lignar 5:63–70Google Scholar
- Korzeniowski W, Żmijewski T, Jankowska B, Kwiatkowska A, Niewęgłowski H, Szaciło K (2002) Percentage of carcass and by products obtained from beavers depending on body weight and sex. Acta Sci Pol Technol 1:13–20Google Scholar
- Magurran AE, Garcia CM (2000) Sex differences in behaviour as an indirect consequence of mating system. J Fish Biol 57:839–857. https://doi.org/10.1111/j.1095-8649.2000.tb02196.x CrossRefGoogle Scholar
- Morgan LH (1868) The American beaver and his works. Lippincott and CO., PhiladelphiaGoogle Scholar
- Mortimer C (1733) The anatomy of a female beaver, and an account of castor found in her. By C. Mortimer, MDRS Secret. Phil. Trans Soc 38: 172–183. https://doi.org/10.1098/rstl.1733.0032
- Rosell F, Sun L (1999) Use of anal gland secretion to distinguish the two beaver species Castor canadensis and C. fiber. Wildl Biol 5:119–123Google Scholar
- Richard-Hansen C, Vié J-C, Vidal N, Kéravec J (1999) Body measurements on 40 species of mammals from French Guiana. J Zool 247:419–428. https://doi.org/10.1111/j.1469-7998.1999.tb01005.x CrossRefGoogle Scholar
- Schwaibold U, Pillay N (2003) The gut morphology of the African ice rat, Otomys sloggetti robertsi, shows adaptations to cold environments and sex-specific seasonal variation. J Comp Physiol B 173:653–659. Google Scholar
- Simonsen TA (1973) Beverens næringsøkologi i Vest-Agder, Meddelelser fra Statens Viltundersøkelser, 2. serie, nr. 39:1–61. (The beaver’s dietary ecology in Vest-Agder. Report from the National Game Survey, 2nd series, pp 39:1–61)Google Scholar
- Spaeth DF, Bowyer RT, Stephenson TR, Barboza PS, Van Ballenberghe V (2002) Nutritional quality of willows for moose: effects of twig age and diameter. Alces 38:143–154Google Scholar
- Wilsson L (1971) Observations and experiments on the ethology of the European beaver (Castor fiber L.) Viltrevy 8:115–166Google Scholar
- Wunder BA (1992) Morphophysiological indicator of the energy states of small mammals. Energetics of gestation and lactation in small mammals: basal metabolic rate and the limits of energy use. In: Tomasi TE, Horton TH (eds) Mammalian energetics: interdisciplinary views of metabolism and reproduction, Cornell University Press, Ithaca, New York, pp 83–105Google Scholar
- Ziółkowska N, Lewczuk B, Petryński W, Palkowska K, Prusik M, Targońska K, Przybylska-Gornowicz B (2014) Light and electron microscopy of the European beaver (Castor fiber) stomach reveal unique morphological features with possible general biological significance. PLoS ONE 9:e94590. https://doi.org/10.1371/journal.pone.0094590 CrossRefPubMedPubMedCentralGoogle Scholar