Phayre's Leaf Monkey

By: Valerie Venier

The Trachypithecus phayrei, otherwise known as Phayre's Leaf Monkey, is an endangered species. The term Trachypithecus refers to blackness, which correlates with the color of the monkey.



Phayre's leaf monkeys can be found in forest regions all across the continent of Asia. The species tends to reside in bamboo, evergreen, or tea forests in particular. Within the forest areas the monkeys spend the majority of their time in the trees, rather than on the forest floor.

Community Interactions:

The two most discernible relationships that Phayre's leaf monkeys have within their habitat are of commensalistic and predator/prey nature. The way the species interacts with different varieties of trees is commensalistic. The monkeys eat the leaves and flowers off of the trees they live in. Because they are adapted to eat 80 different types of leaves it doesn't harm the tree, while the monkeys benefit since they are getting the nutrients they need. Occasionally when foliage isn’t as abundant the monkeys will eat bamboo shoots, which doesn't harm the plant either. The Phayre's leaf monkey's other relationship is predator/prey with native tribes that inhabit the same area as the monkeys. The tribes often hunt the leaf monkey and kill them for food.

Feeding Relationships:

Phayre's leaf monkey is an herbivore, but could also be considered a folivore, which means they eat leaves. The monkeys eat over 80 different types of leaves from the trees that they live in.


Phayre’s Leaf Monkey shies away from encounters with other species, instead they spend their days eating foliage from trees in bamboo forests, evergreen forests, or tea forests. Phayre’s leaf monkeys spend approximately 75% of their time in the trees eating leaves.

Population Dynamics:

Two factors that have effected the population of the Phayre's leaf monkeys are deforestation and pollution. Deforestation, which is a density dependent factor, has reduced the carrying capacity. Pollution, on the other hand, is density independent. Because of deforestation and pollution, the number of this species has nearly diminished.

Human Impacts:

Humans cause deforestation and are also at fault for the construction of paper mills, tea gardens, lumber yards, etc. that destroy Phayre’s leaf monkeys’ habitats. Not only do humans impact the species through this, but tribes of people within the regions that the monkeys live hunt them for food, which damages the population.

Cellular respiration

The Phayre’s Leaf monkey is an animal, so it does not perform photosynthesis. Instead, this species performs cellular respiration. To do this there are certain organelles within the cell that are necessary. The Mitochondria is required for converting the glucose that is produced from cellular respiration into ATP.


Phayre’s leaf monkey reproduces sexually because it is a mammal. The cells that make up the organism reproduce through both meiosis, and mitosis. Within a group of Phayre’s leaf monkey there is generally one alpha male that mates with several of the females, rather than pairing off to produce offspring.


The Phayre’s leaf monkey is a part of the Animalia kingdom, the Chordata phylum, the Mammalia class, the Primates order, and the Cercopithecidae family. Some organisms that are related to Phayre’s leaf monkey on a genus level are most species of lutungs, in specific, the Dusky leaf monkey is very similar to the Phayre’s leaf monkey. Since Phayre’s leaf monkey is a mammal there is a wide range of species that are related on the class level. The spectrum ranges from other monkeys like the old world monkey, all the way to species like lions, tigers, elephants, and even humans. In its habitat, the Phayre’s leaf monkey’s niche is eating a variety of leaves from trees. Because the species eats over 80 different types of leaves they have a highly adapted stomach and enhanced salivary glands that enable them to break down the cellulose and tough materials that are found in the leaves they eat.

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