A study done by L.E. Miller (2002) reported the presense of predator-sensitive foraging among many primate species including the ring-tailed lemur. As defense against predation, small groups of ring-tails tend to stay together when entering new territory. This supports the notion of predator-sensitive foraging because new areas will likely contain unknown risks and smaller groups are less able to fend off predators. There may be a "group size effect" because large groups have been found to spread out more when entering a new territory. Large groups also were more willing to enter new regions of the forest, therefore increasing both fruit feeding and predator encounters. When predation pressure was high, the smaller group avoided foraging on the ground (resulting in reduced leaf and fruit intake), changing its foraging behavior in order to lessen the chances for a predator attack. The smaller group was also more likely to associate with sifakas, perhaps in order to increase apparent group size. Larger groups showed fewere anti-predator behaviors; because of their larger size they were probably able to take more chances in foraging than the smaller groups (Miller 2002). This study confirms that predator sensitivity results in tradeoffs between safety and foraging success and that ring-tailed lemurs will behave in a way that balances these variables according to their social environments (group size).

Anti-predator defense includes vigilance and mobbing as well as alarm calling (Miller 2002). Ring-tailed lemurs have several alarm calls to alert group members to potential danger (Haring 2004). The troop will shriek when it sees a low-flying hawk. When a ground predator is spotted, the animals that spot the predator will beging a series of single clicks; these will raise in intensity to click-grunts which grow louder and more frequent until one animal begins to bark (high pitched call in short bursts), after which the rest of the troop joins in the barking in perfect synchrony whether or not they have seen the predator (Jolly 1966).

In agreement with this was another study that found that ring-tailed lemurs use different calls in response to different classes of predators. Optimal modes of escape differed for raptors as opposed to terrestrial carnivores and each mode of escape increased the lemurs' vulnerability to predators of the other class (Pereira 1991).