reindeer herds visit the grasslands in summer. other animals include red and arctic foxes, wolverines, moose, otters, and lynx in the southern areas. american minks, which were released near the olenitsa river in 1935–1936, are now common throughout the peninsula and are commercially hunted. beavers, which became endangered by 1880, were re-introduced in 1934–1957. all in all, thirty-two species of mammals and up to two hundred bird species inhabit the peninsula.