“…In studying predation, primatologists have paid particular attention to whether adult males defend group members during predator attacks [DeVore and Washburn, 1963;Busse, 1976;Kappeler, 2000;van Schaik and Janson, 2000], the influence of predation on body size, on activity pattern and on degree of arboreality [Crook, 1972;Alexander et al, 1979;Popp, 1983;Gaulin and Sailer, 1984;Cheney and Wrangham, 1987;Isbell, 1994], whether predation pressure functions as the primary selective force favoring group living [van Schaik, 1983;Dunbar, 1988;Janson, 1992;Gursky, 2002a] as well as whether predation occurs frequently enough to influence primate demographic patterns [Caughley, 1977;Janson, 1984;Cheney and Seyfarth, 1985].…”