This is a list of known fatal bear attacks that occurre in North America by decade in reverse chronological order. Three species of bear, the Brown Bear (Ursus arctos), the American Black Bear (Ursus americanus) and the Polar Bear (Ursus maritimus) are identified in the article. The Grizzly Bear (Ursus arctos horribilis), the Kodiak Bear and the Mexican Brown Bear are treated as subspecies of the Brown Bear. There were about 52 recorded deaths due to black bears between 1900 and 2003 and about 50 deaths due to brown bears and about 5 due to polar bears in the same period. The most recent data is the most reliable and complete, but does not necessarily include all of the fatal attacks that have occurred in North America. Prior to recent decades bear attacks were not well documented, particularly those which took place in isolated regions. As a result there were more attacks and fatalities than have been recorded as shown here, particularly in Canada and Alaska.