ice, and open water, and for hunting the seals which make up most of its diet. Although most polar bears are born on land, they spend most of their time at sea. Their scientific name means "maritime bear, and derives from this fact. Polar bears can hunt their preferred food of seals from the edge of sea ice, often living off fat reserves when no sea ice is present. The polar bear is classified as a vulnerable species, with eight of the nineteen polar bear subpopulations in decline.[6] For decades, large scale hunting raised international concern for the future of the species but populations rebounded after controls and quotas began to take effect.[citation needed] For thousands of years, the polar bear has been a key figure in the material, spiritual, and cultural life of Arctic indigenous peoples, and polar bears remain important in their cultures.
(2010) Õpetajate poolt väärtustatud toetussüsteemid uurimusliku õppe läbiviimiseks loodusteaduste tundides. [Magistritöö] http://www.google.ee/url? sa=t&rct=j&q=mugavusvalim&source=web&cd=10&ved=0CFYQFjAJ&url=http%3A%2F%2Fwww.ut.ee %2Fbiodida%2Fmagfail%2Fkristi_rikka_bioloogiaop_magtoo2010.pdf&ei=10vcTvq7A4md wbytrCRAQ&usg=AFQjCNFa4Wkos8yMcQvoaYgGnrg5keMJIw&cad=rja (25.03.2012). Rudolph, A.E., Craford, N.D., Latkin, C., Heimer, R., Benjamin, E.O., Jones, K.C., Fuller, C.M. (2011) Subpopulations of Illicit Drug Users Reached by Targeted Street Outreach and Respondent Driven Sampling Strategies: Implications for Research and Public Health Practice. Annals of Epidemiology, Vol.21, No 4, p 280289. Salganik, M.J., Heckathorn, D.D. (2004). Sampling and Estimation in Hidden Populations Using RespondentDriven Sampling. Sociological Methodology, 34, 193239. Salla, KA. (2011) Noorte subkultuur erikoolis kui totaalses asutuses. [Magistritöö]
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