Zoo Animals and Their Human Audiences: What is the Visitor Effect?
The presence of human visitors has been shown to affect the behaviour of several different mammalian species in a number of different zoos, but the behavioural changes observed are not always consistent with a simple ‘stressful influence’ explanation. Data for non-primate species are too sparse to draw meaningful conclusions; but for primates, the evidence reviewed […]
Participation in group defence: proximate factors affecting male behaviour in wild white-faced capuchins
When two social groups of the same species confront each other, what factors influence whether individuals participate in the struggle for defence of their group and its resources? In white-faced capuchin monkeys, Cebus capucinus, adult males play an important role in the outcome of intergroup encounters by cooperating aggressively against their opponents. However, not all […]
Rival Presence Leads to Reversible Changes in Male Mate Choice of a Desert Dwelling Ungulate
Gregarious animals often face the problem of unintended interception of information by group members, as almost all communicatory interactions occur in a public domain. For example, individuals may observe and copy the choices of others. Male mate choice copying in species with internal fertilization remains a conundrum, as both the copying and the copied male […]
Sneaky Monkeys: An Audience Effect of Male Rhesus Macaques (Macaca mulatta) on Sexual Behavior
Males and females have different sexual interests and subsequently may show conflicting sexual strategies. While dominant males try to monopolize females, promiscuity benefits females and subordinate males. One way to escape monopolization by dominant males is to copulate in their absence. We tested this inhibitory effect of males on the sexual behavior of their group […]
Feeding nestlings does not function as a signal of social prestige in cooperatively breeding chestnut-crowned babblers
Humans are commonly concerned with social status, and often cooperate in the presence of others in an attempt to signal their potential as a social or reproductive partner. Whether or not cooperation might signal prestige in nonhuman animals is seldom tested and poorly understood. We investigated whether male chestnut-crowned babblers, Pomatostomus ruficeps, that are unrelated […]
Chimpanzee food calls are directed at specific individuals
If primates were capable of vocalizing to inform a receiver about an external entity, it would represent an important element of continuity with human language. We tested experimentally whether chimpanzee rough grunts, which function to refer to food, are produced selectively, indicating voluntary control, and whether they are directed at specific individuals. These are prerequisites […]