Dr. Jon Aars is a senior research scientist at the Norwegian Polar Institute, Norway. He holds a M.S. from University of Oslo (1994) and a Ph.D. from the same university (1998). From 1991 to 2002, he worked with small rodent demography and genetics, in fragmented landscapes (landscape ecology and metapopulation systems). Since 2003, he has worked on polar bear ecology in Svalbard, Norway. He has been working on space use, diseases, population genetics, evolutionary genetics, feeding ecology, and toxicology. However, his main interest has been population ecology.