Politics of monkeys

Hanuman langurs (Presbytis entellus) considered sacred are found throughout India. They generally live in groups with a complex social organization having dominance hierarchies.

- S. K. SAIDAPUR

They are both polygynous and polyandrous. A group may consist of one male, several females and their offspring or all male groups. Multiple-male groups consist of many males and females of different ages. Single males, driven out of the group wander alone.

Hanuman langurs are known for flaunting infanticide phenomenon that was discovered in Dharwad, Jodhpur and Abu some fifty years ago. Briefly, in mixed compositions the dominant male monopolizes all females. Subordinate males can mate with females stealthily when dominant male is not in the vicinity. Dominance of larger male is maintained due to his aggressive powers which enables him mating success, and siring as many offspring as possible. In a way langurs live in a harem.

A subordinate male member of langur troop is incapable of taking head-on the resident dominant male and defeat him. Consequently, the subordinate males face a setback in accomplishing mating success and siring offspring. As a result, they hatch a plot to jointly fight the dominant male and drive him away. Then, the subordinate males (who are of comparable strength) fight among themselves; the winner becomes new resident commander and takes over the troop (harem).