Howler Monkeys and Harpy Eagles: A Communication Arms Race

Abstract

Predation is considered by many researchers to be a selective pressure and strong evolutionary driving force in natural ecosystems. Predation phenomena are dynamic interactions that by definition need more than one agent: at least one predator and one prey. The interaction gets exponentially more complicated when we consider multiple agents and different strategies. These predator-prey interactions can be viewed as evolutionary arms races. There have been numerous studies on prey adaptations (Blumstein et al., 2000; Hauser & Caffrey, 1994; Marler et al., 1992; Endler, 1991; Cheney & Seyfarth, 1990; Hauser & Wrangham, 1990; Ryan et al., 1982), but few report both detailed adaptive responses to predation and ways predators can improve their killing efficiency (Berger et al., 2001). This lack of knowledge is even more striking for predation upon primates (Shultz et al., 2004; Gil-da-Costa et al., 2003; Zuberbühler, 2000a; Zuberbühler et al., 1999).