References

 

Woolverton, et al. Arctic Tale. National Geographic, 2007.

Curtsinger, Bill. Naturaleza al extremo. Numen, 2005.

Animals, a visual encyclopedia. Smithsonian. 2012. Pp. 86,87.

Alderton, David. The encyclopedia of animals. Chartwell books, Inc., 2009. Pág. 149

http://seaworld.org/en/animal-info/animal-infobooks/walrus/

http://alaskafisheries.noaa.gov/newsreleases/2013/walrushaulout093013.htm

http://www.nmfs.noaa.gov/pr/species/mammals/pinnipeds/

http://en.wikipedia.org/wiki/Walrus

http://animals.nationalgeographic.com/animals/mammals/walrus/

http://wwf.panda.org/about_our_earth/species/profiles/mammals/walrus/

http://news.bbc.co.uk/2/hi/programmes/6065512.stm