1-4-2015 ELEPHANTA ISLAND, MUMBAI - BONNET MACAQUE (Macaca radiata)

The bonnet macaque are very social animals and they communicate in a different range of facial expressions. The bonnet macaque, like other macaques, shares a linear dominance hierarchy; the alpha male is the most dominant male of the troop, followed by a beta male and a gamma male, and so on according to their dominance. Similarly, females also follow this linear hierarchy. The male and female hierarchies are different and of a non-overlapping or non-mixing types. Males are usually dominant over females. In their social groups females tend to stay in the same group they were born in, whereas males tend to disperse.

The females' dominance hierarchy is stable, whilst the males' dominance hierarchy is very dynamic. In the male hierarchy, males close in rank often fight to rise in rank. A male has the best chance of obtaining a high rank in his prime age, resulting in the greatest benefits to reproduction. High-ranking individuals have first access to breeding females.

Females are receptive during only a few months in a year, resulting in competition between males. In this situation, the ranks established by aggressive encounters come into play. Most of these aggressive encounters are easily resolved, but competition between similarly built or similarly aggressive males results in brutal and sometimes fatal fights. Female bonnet macaques attempt kidnappings of lower-ranking females. These are done mostly by mother females and the majority of the time they are not successful in completing it. Different males may employ various means to rise in rank.

Coalition formation between unrelated males to oust a more dominant male has been observed. Males often move from troop to troop to gain a higher rank with the resulting benefits. However, males remaining in a single troop have been observed to rise to become dominant male of that troop.

An important note is male bonnet macaques are generally far more laid back and carefree in their social lives than many other macaque species. Competition among male bonnet macaques is much more subdued and there is a much higher emphasis on pacifism. Male bonnet macaques groom each other, hug each other, sleep near each other, play together and engage in male-male mounting as a social defuser. While assertive males may take measures to monopolize matings, they cannot control females and these females will mate promiscuously, as macaques do. Some mysterious environmental pressures must have driven the bonnet macaque to form an unusually egalitarian social structure. Why this trend crops up convergently in separate macaque species rather than being an ancestral macaque trait is an enigma. A possible driving force may be these pacifist species inhabit more fertile habitats with more abundant food. Bonnet macaques are also strong swimmers.

In the case of females, the stable dominance hierarchy is a result of female philopatry, when individuals tend to remain with the troop into which they are born. This results in the formation of matrilinear groupings of closely related females.