Rhesus Macaques: Fascinating Old World Monkeys
Rhesus macaques, more often referred to as Rhesus monkeys and also known as Nazuri monkeys, have the widest geographical distribution of any non-human primate and are found in a broad range of habitats in Bangladesh, as well as India, Pakistan, Nepal, Thailand, Burma, Afghanistan, Vietnam and southern China. These fascinating mammals are the most readily recognized species of Old World monkeys and, as they readily interact with humans, they are often found near, or even in, suburban areas where they are either revered, or considered to be a pest, depending on the belief system of the residents.
The Rhesus macaque has an expressive, pink-colored face framed by brown or grey close-cropped fur which also covers the rest of its body. Adult males measure around 53 cm from the base of the tail to the top of the head, and weigh on average about 7.7 kgs. Their tails measure between 20.7 and 22.9 cm in length. Females tend to be smaller and, while not being dominant, because the males are frequently absent from the troop, females are known to take charge.
As diurnal animals, Rhesus macaques sleep at night and are active in the day. While they are quite at home in trees, they tend to spend much of their time on the ground foraging for something to eat and grooming one another. Their preferred food is fruit, but they also eat seeds, roots, bark, cereals and small insects, such as grasshoppers, ants, termites and beetles. They are able to temporarily hoard their food in the pouch-like cheeks.
They are social animals, and live in troops that can be as small as 20 or as large as 200 individuals. Females tend to outnumber males by 4:1 and both sexes adhere to a hierarchy. Among females the hierarchy is matrilineal, with a young female’s ranking being dependent on the rank of her mother. It has been noted that the youngest females in the family group outrank their older sisters and this is thought to relate to the fitness and fertility of the younger sibling. There is seldom open squabbling about this pecking order, each female accepting her role in the troop. With males, juvenile macaques remain within the matrilineal line until the age of four or five years, when they are driven out by the dominant male of the group to fend for themselves.
While the family dynamics of Rhesus macaques are fascinating, their range of facial expressions, vocalizations and body language are just as important to each individual’s standing in the family group – and can be very entertaining to watch. So, when exploring the national parks and natural areas of Bangladesh and you come across a troop of Rhesus macaques, be sure to take some time to simply watch them and be entertained.