References
1. Arkive. 2015. Common otter (Lutra lutra). Available: http://www.arkive.org/common-otter/lutra-lutra. Accessed March 2, 2015.
2. Arkive. 2015. North American otter (Lontra canadensis). Available: http://www.arkive.org/north-american-otter/lontra-canadensis. Accessed March 2, 2015.
3. Baitchman, E. J., G. V. Kollias. 2000. Clinical anatomy of the North American river otter (Lontra canadensis). J. Zoo. Wildlife. Med. 31(4):473-483
4. Black, J.M. 2009. River otter monitoring by citizen science volunteers in northern California: social groups and litter size. Northwestern. Nat. 90(2): 130-135.
5. Chadwick, E., and E. Sherrard-Smith. 2010. Pregnancy among otters (Lutra lutra) found dead in England and Wales: foetal development and lack of seasonality. IUCN Otter Spec. Group Bull. 27(1): 33-41.
6.Clavero, M., J. Prenda, and M. Delibes. 2003. Trophic diversity of the otter (Lutra lutra l.) in temperate and Mediterranean freshwater habitats. J. Biogeogr. 30: 761-769.
7. Crowley, S., C.J. Johnson, and D.P. Hodder. 2013. Spatio-temporal variation in river otter (Lontra canadensis) diet and latrine site activity. Ecoscience. 20(1): 28-39.
8. Davis, H.G., R.J. Aulerich, S.J. Bursian, J.G. Sikarskie, and J.N. Stuht. 1992. Feed consumption and food transit time in northern river otters (Lutra canadensis). J. Zoo. Wildl. Med. 23(2): 241-244.
9. Gorman, T.A., J.D. Erb, B.R. McMillan, D.J. Martin, and J.A. Homyack. 2006. Site characteristics of river otter (Lontra canadensis) natal dens in Minnesota. Am. Midl. Nat. 156: 109-117.
10. Hamilton, W. J., W. R. Eadie. 1962. Reproduction in the otter, Lutra canadensis. J. Mammal. 45(2): 242-252.
11. Hauer, S., H. Ansorge, and O. Zinke. 2002. Reproductive performance of otters Lutra lutra (Linnaeus, 1758) in Eastern Germany: low reproduction in a long-term strategy. Biol. J. Linn. Soc. 77: 329-340.
12. Iversen, J.A. 1972. Basal energy metabolism of mustelids. J. Comp. Physiol. 81(4): 341-344.
13. Jackson, H.H.T. 1961. Mammals of Wisconsin. pg. 383
14. Koepfli, K. P., K. A. Deere, G. J. Slater, C. Begg, K. Begg, L. Grassman, M. Lucherini, G. Veron, and R. K. Wayne. 2008. Multigene phylogeny of the Mustelidae: resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation. BMC. Biol. 6:10.
15. Kruuk, H. 2006.Otters ecology, behaviour and conservation.Oxford University Press, New York, NY.
16. Kruuk, H., A. Moorhouse, J.W.H. Conroy, L. Durbin, and S. Frears. 1989. An estimate of numbers and habitat preferences of otters Lutra lutra in Shetland, UK. Biol. Cons. 49: 241-254.
17. Lanszki, J., M. Molnar, and T. Molnar. 2006. Factors affecting the predation of otter (Lutra lutra) on European pond turtle (Emys orbicularis). J. Zool. 270: 219-226.
18. Larivière, S., L.R. Walton. 1998. Lontra canadensis. Mamm. Species. 587: 1-8.
19. Madsen, A.B., A. Prang. 2001. Habitat factors and the presence or absence of otters Lutra lutra in Denmark. Acta. Theriol. 46(2): 171-179.
20. Miller Ben Shaul, D. 1963. The composition of the milk of wild animals. Int. Zoo. Yearb. 4(1): 333-342.
21. Reed-Smith, J. 2001. North American river otter. 2nd ed.
22. Reid, D.G., T.E. Code, A.C.H. Reid, and S.M. Herrero. 1994. Spacing, movements, and habitat selection of the river otter in boreal Alberta. Can. J. Zool. 72: 1314-1324.
23. Ruiz-Olmo, J., A. Batet, and F. Manas. 2011. Factors affecting otter (Lutra lutra) abundance and breeding success in freshwater habitats of the northeastern Iberian Peninsula. Eur. J. Wildl. Res. 57: 827-842.
24. Ruiz-Olmo, J., A. Loy, C. Cianfrani, P. Yoxon, G. Yoxon, P.K. de Silva, A. Roos, M. Bisther, P. Hajkova, and B. Zemanova. 2008. Lutra lutra. The IUCN Red List of Threatened Species.
25. Sales-Luis, T., N.M. Pedroso, and M. Santos-Reis. 2007. Prey availability and diet of the Eurasian otter (Lutra lutra) on a large reservoir and associated tributaries. Can. J. Zool. 85: 1125-1135.
26. Serfass, T. and P. Polechla. 2008. Lontra canadensis. The IUCN Red List of Threatened Species.
27. Stearns, C.R. and T.L. Serfass. 2011. Food habits and fish prey size selection of a newly colonizing population of river otters (Lontra canadensis) in eastern North Dakota. Am. Midl. Nat. 165: 169-184.
28. Stevens, C.E., I.D. Hume. 1995. The mammalian gastrointestinal tract. In: Comparative physiology of the vertebrate digestive system. Cambridge University Press, New York, pp. 59.
29. Williams, D.L., V.R. Simpson, and A. Flindall. 2004. Retinal dysplasia in wild otters (Lutra lutra). Vet. Rec. 155: 52-56.
2. Arkive. 2015. North American otter (Lontra canadensis). Available: http://www.arkive.org/north-american-otter/lontra-canadensis. Accessed March 2, 2015.
3. Baitchman, E. J., G. V. Kollias. 2000. Clinical anatomy of the North American river otter (Lontra canadensis). J. Zoo. Wildlife. Med. 31(4):473-483
4. Black, J.M. 2009. River otter monitoring by citizen science volunteers in northern California: social groups and litter size. Northwestern. Nat. 90(2): 130-135.
5. Chadwick, E., and E. Sherrard-Smith. 2010. Pregnancy among otters (Lutra lutra) found dead in England and Wales: foetal development and lack of seasonality. IUCN Otter Spec. Group Bull. 27(1): 33-41.
6.Clavero, M., J. Prenda, and M. Delibes. 2003. Trophic diversity of the otter (Lutra lutra l.) in temperate and Mediterranean freshwater habitats. J. Biogeogr. 30: 761-769.
7. Crowley, S., C.J. Johnson, and D.P. Hodder. 2013. Spatio-temporal variation in river otter (Lontra canadensis) diet and latrine site activity. Ecoscience. 20(1): 28-39.
8. Davis, H.G., R.J. Aulerich, S.J. Bursian, J.G. Sikarskie, and J.N. Stuht. 1992. Feed consumption and food transit time in northern river otters (Lutra canadensis). J. Zoo. Wildl. Med. 23(2): 241-244.
9. Gorman, T.A., J.D. Erb, B.R. McMillan, D.J. Martin, and J.A. Homyack. 2006. Site characteristics of river otter (Lontra canadensis) natal dens in Minnesota. Am. Midl. Nat. 156: 109-117.
10. Hamilton, W. J., W. R. Eadie. 1962. Reproduction in the otter, Lutra canadensis. J. Mammal. 45(2): 242-252.
11. Hauer, S., H. Ansorge, and O. Zinke. 2002. Reproductive performance of otters Lutra lutra (Linnaeus, 1758) in Eastern Germany: low reproduction in a long-term strategy. Biol. J. Linn. Soc. 77: 329-340.
12. Iversen, J.A. 1972. Basal energy metabolism of mustelids. J. Comp. Physiol. 81(4): 341-344.
13. Jackson, H.H.T. 1961. Mammals of Wisconsin. pg. 383
14. Koepfli, K. P., K. A. Deere, G. J. Slater, C. Begg, K. Begg, L. Grassman, M. Lucherini, G. Veron, and R. K. Wayne. 2008. Multigene phylogeny of the Mustelidae: resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation. BMC. Biol. 6:10.
15. Kruuk, H. 2006.Otters ecology, behaviour and conservation.Oxford University Press, New York, NY.
16. Kruuk, H., A. Moorhouse, J.W.H. Conroy, L. Durbin, and S. Frears. 1989. An estimate of numbers and habitat preferences of otters Lutra lutra in Shetland, UK. Biol. Cons. 49: 241-254.
17. Lanszki, J., M. Molnar, and T. Molnar. 2006. Factors affecting the predation of otter (Lutra lutra) on European pond turtle (Emys orbicularis). J. Zool. 270: 219-226.
18. Larivière, S., L.R. Walton. 1998. Lontra canadensis. Mamm. Species. 587: 1-8.
19. Madsen, A.B., A. Prang. 2001. Habitat factors and the presence or absence of otters Lutra lutra in Denmark. Acta. Theriol. 46(2): 171-179.
20. Miller Ben Shaul, D. 1963. The composition of the milk of wild animals. Int. Zoo. Yearb. 4(1): 333-342.
21. Reed-Smith, J. 2001. North American river otter. 2nd ed.
22. Reid, D.G., T.E. Code, A.C.H. Reid, and S.M. Herrero. 1994. Spacing, movements, and habitat selection of the river otter in boreal Alberta. Can. J. Zool. 72: 1314-1324.
23. Ruiz-Olmo, J., A. Batet, and F. Manas. 2011. Factors affecting otter (Lutra lutra) abundance and breeding success in freshwater habitats of the northeastern Iberian Peninsula. Eur. J. Wildl. Res. 57: 827-842.
24. Ruiz-Olmo, J., A. Loy, C. Cianfrani, P. Yoxon, G. Yoxon, P.K. de Silva, A. Roos, M. Bisther, P. Hajkova, and B. Zemanova. 2008. Lutra lutra. The IUCN Red List of Threatened Species.
25. Sales-Luis, T., N.M. Pedroso, and M. Santos-Reis. 2007. Prey availability and diet of the Eurasian otter (Lutra lutra) on a large reservoir and associated tributaries. Can. J. Zool. 85: 1125-1135.
26. Serfass, T. and P. Polechla. 2008. Lontra canadensis. The IUCN Red List of Threatened Species.
27. Stearns, C.R. and T.L. Serfass. 2011. Food habits and fish prey size selection of a newly colonizing population of river otters (Lontra canadensis) in eastern North Dakota. Am. Midl. Nat. 165: 169-184.
28. Stevens, C.E., I.D. Hume. 1995. The mammalian gastrointestinal tract. In: Comparative physiology of the vertebrate digestive system. Cambridge University Press, New York, pp. 59.
29. Williams, D.L., V.R. Simpson, and A. Flindall. 2004. Retinal dysplasia in wild otters (Lutra lutra). Vet. Rec. 155: 52-56.