I examined historical records of unprovoked attacks by cougars on humans in the U.S. and Canada during 101 years (1890-1990). There were 9 attacks resulting in 10 human deaths and at least 44 nonfatal attacks. In a recent paper, I listed these attacks and discussed them in considerable detail (Beier 1991). Although extremely rare, attacks on humans have increased markedly during the last 2 decades, during which cougar numbers and human use of cougar habitats have increased. There is no substantial evidence that habituation underlies this increase in attacks. The data provide weak support for the notion that an attacking cougar may be disposed to attack humans again. Warnings apparently do not deter people from visiting parks in cougar habitat.