Dusky leaf monkey facts for kids

Quick facts for kids Dusky leaf monkey
Conservation status
Endangered (IUCN 3.1)
Scientific classification
Genus:	Trachypithecus
Species:	obscurus
Dusky leaf monkey range

The dusky leaf monkey (Trachypithecus obscurus), also called the spectacled langur, is a type of primate in the monkey family, Cercopithecidae. You can find these monkeys in Peninsular Malaysia, Myanmar, and Thailand. Sometimes, they are even seen in Singapore.

During the day, these small monkeys split into smaller groups. They look for leaves and fruit to eat in the tropical forests. The IUCN says the number of dusky leaf monkeys is shrinking. This is because their homes are being destroyed, and some are hunted. In 2015, the IUCN listed them as an endangered species.

What Kind of Monkey Is It?

The dusky leaf monkey belongs to the monkey family called Cercopithecidae. Within this family, it is part of the Trachypithecus group. Most scientists agree with this. However, some think it should be in a different group called Presbytis.

Different Types of Dusky Leaf Monkeys

Scientists also discuss how many different types, or subspecies, of dusky leaf monkeys there are. Some say there are 11, while others say there are seven. Currently, seven subspecies are officially recognized:

• T. o. obscurus
• T. o. flavicauda
• T. o. halonifer
• T. o. carbo
• T. o. styx
• T. o. seimundi
• T. o. sanctorum

What Do They Look Like?

Dusky leaf monkeys can have different fur colors. This depends on which subspecies they are. When they are born, baby dusky leaf monkeys have bright orange fur. But as they grow up, their fur changes color.

Their belly fur is usually lighter than the fur on their back. Their back fur can be shades of brown, black, or grey. A cool thing about them is the bright white fur around their eyes. This makes them look like they are wearing glasses!

Dusky leaf monkeys are fairly small. Male monkeys are usually a bit bigger than females. For example, one study found that male dusky leaf monkeys weighed about 7.39 kilograms (around 16 pounds). Females weighed about 6.47 kilograms (around 14 pounds). This means females are about 12% smaller than males.

Where Do They Live?

While the dusky leaf monkey's fur can develop into shades of grey, brown, or black, they are born with an orange coat.

Dusky leaf monkeys live in tropical forests across Malaysia, Myanmar, and Thailand.

Dusky Leaf Monkeys in Singapore

Sometimes, these monkeys are seen in Singapore. Between 2019 and 2020, three dusky leaf monkeys were found in northern Singapore. This area is close to the water that separates Singapore and Malaysia. Scientists believe these monkeys might swim to Singapore.

Researchers are a bit worried about these monkeys moving to Singapore. They could compete with local animals for food like leaves. They might also spread diseases to other animals that aren't used to them. However, these monkeys are not considered an invasive species. This is because they move to Singapore naturally, without human help.

How Do They Behave and What Do They Eat?

Dusky leaf monkeys feed in the emergent and canopy layers.

Scientists have studied how dusky leaf monkeys spend their time in Malaysia. For example, one study in 2016 found that these monkeys spent:

• 40% of their time resting
• 33% of their time eating
• 20% of their time moving

They also spent a little time grooming each other (4%), playing (2%), and looking for food (1%). Another study found similar results, with monkeys spending about 40% of their day eating.

Dusky leaf monkeys live in groups called troops. When they look for food, these troops often split into smaller groups. They usually eat leaves that grow high up in the forest canopy. They also rest high up in the trees after finding their food. While they eat more leaves, they prefer to eat fruit when it's available. The amount of fruit depends on the season.

These monkeys usually don't fight much within their groups. If they do fight, they tend to make up very quickly. One study found that they can resolve conflicts in as little as 60 seconds! They might hug each other to show they are friends again.

Mating Habits

Male dusky leaf monkeys can reproduce all year long. This means they don't have a specific mating season. Scientists think this might be because of the warm weather in Southeast Asia all year round. Many animals that have a mating season do so when the weather gets warmer.

Protecting the Dusky Leaf Monkey

Since 2015, the dusky leaf monkey has been listed as an endangered species on the IUCN Red List. A big reason for this is that human activities are destroying their natural homes in Southeast Asian forests. This has led to their numbers going down.

However, there are other dangers too:

• Predators: Sometimes, packs of pet dogs hunt and kill dusky leaf monkeys.
• Roads: Building roads through forests has caused many monkeys to be hit by cars. This is a major threat to their survival.
• Hunting: Dusky leaf monkeys are sometimes hunted for their meat. They are also seen as pests by farmers because they eat leaves on plantations. In the 1960s, some business owners in Malaysia would shoot them.
• Pet Trade: Baby dusky leaf monkeys are sometimes caught and sold as pets around the world. Sadly, these babies often don't get the right care and die.

People are working to help save the dusky leaf monkey. In 1977, the dusky leaf monkey was added to Appendix II of the CITES agreement. This means that trading these monkeys is heavily controlled and often illegal. This helps protect species that are threatened or endangered.

Images for kids

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  Dusky leaf monkey - Kaeng Krachan National Park

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  Adult male spectacled langur

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  Dusky leaf monkey - Ko Tarutao

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