Blog | Monkeys of Swayambhunath: How did they evolve? What do they signify?

Sushil Hamal

  • Read Time 4 min.

Swayambhunath is an ancient stupa (a dome-shaped building erected as a Buddhist shrine) on a hill in the Kathmandu Valley, northwest of the city of Kathmandu.

Shortly after climbing the first steps, you can see a macaque. They are one of the most famous monkey species of the Old World (Cercopithecidae). Cercopithecidae is a family of monkeys native to Africa and Asia (New World monkeys are from Central and South America and Mexico). Rhesus monkeys have the largest geographic range of any non-human primate. They inhabit a wide range of altitudes and habitats, and their average life expectancy in the wild is 25 years, with a maximum life expectancy of 40 years recorded. They live in active, noisy troops that can number up to 200 animals.

Rhesus monkeys communicate using a variety of facial expressions, vocalizations, body postures, and gestures. They have demonstrated a range of complex cognitive abilities and even self-reliance. They are mostly herbivores and feed mainly on fruits, but many also eat seeds, roots, buds, bark, grains, insects, and small animals

These monkeys are considered sacred by devotees who visit and live near these ancient shrines. There is a very popular mythology that continues to be told from generation to generation among the inhabitants about the existence of these macaques. According to the Swayambhu Purana, the entire valley was once filled with a huge lake from which a lotus grew. The valley came to be known as Swayambhu, meaning “self-created.” The name comes from an eternal, self-existing flame (svyaṃbhu), over which a stupa was later erected. They are sacred because Manjushree, the bodhisattva of wisdom and learning, built the hill on which the stupa stands. He was supposed to leave his hair short, but he let it grow long and head lice grew. It is said that the head lice turned into these monkeys.

Dr Mukesh Kumar Chalise, an associate professor of zoology at Tribhuvan University, who has been observing these monkeys since 1991, has recorded some 425-450 individuals in Swayambhunath. However, the number of individuals has remained remarkably constant. Such a high number of macaques in such a small area of 2.5 hectares due to human food scraps, which under normal conditions could only support 40-50 individuals.

The increased contact with humans has already begun to have a detrimental effect on the health of the monkeys in Swayambhunath. The extra food provided by people visiting the stupa seems to be a charitable action, but giving food to the monkeys is doing more harm than good, one can simply say it is “unhealthy and unnatural.” While the population is booming, the quality of life of the rhesus monkeys in the city has suffered greatly compared to their counterparts in the countryside. The large population results in great competition among the monkeys, and the abundance and nature of the food have resulted in highly unusual reproductive habits. Sometimes the mother monkey even gives birth to twins and triplets, but research has shown that these cannot survive for more than a month because the mother does not provide enough milk. In their natural habitat [forest], the macaque mother starts reproducing at the age of four or five and allows at least two years between pregnancies, but in Swayambhunath, female monkeys start giving birth at the age of two and continue to do so about every six months. Frequent and early pregnancies have adverse effects on the health of both mother and child. This problem is directly related to the high percentage of human food in their diet. In general, modified foods and malnutrition in macaque can lead to excessive estrogen production, which causes infertility and breast tissue diseases.

The term used to describe human food donations is ‘wildlife feeding,’ defined as “offering food to an animal beyond its natural supply and the quality of the animal’s environment.” Recent studies have found that the effects of provisioning, which occur all over the world, are far-reaching and severe. Processed human foods are high in fat and sugar, causing primates to gain weight and putting them at increased risk for cardiovascular disease due to high cholesterol levels.

Recent studies have found the presence of human diseases such as influenza, tuberculosis, whooping cough, and skin diseases in the monkey population. This finding proves the supply theory of disease transmission between monkeys and humans. As a result, monkeys in urban areas live no longer than ten to twelve years, when they should live up to twenty years. Diseases can also be transmitted from monkeys to humans, such as the herpes B virus.

The lack of fruits and seeds in the diet also prevents the monkeys from fulfilling their natural role as seed dispersers through their excretions. The most striking effect on these monkeys is that they are greedy, opportunistic, and quarrelsome–they frequently fight over food and have learned to steal from and rob humans. Such behavior is not unheard of in rhesus monkeys in rural areas, where they live entirely in their natural habitats. Increased aggression damages their interpersonal relationships and diminishes the value of socialization and group cohesion

Although coexistence with animals is an integral part of Nepali culture and the presence of monkeys in temples shows harmony with human nature, we should not forget that the feeding of our native monkeys, which seems to us the most charitable, must limit human food to save the ecosystem. Their good health is very important for the natural biodiversity in Kathmandu.