Rare Monkey Species: The World Most Threatened Primates

Some monkeys number only a few hundred individuals. Rarity in primates almost always comes from the same combination: a small natural range, heavy hunting pressure and forest converted to farmland faster than the species can adapt.

Key takeaways

• Several monkey species have fewer than 300 individuals left in the wild.
• Rarity is usually driven by small range plus hunting plus habitat conversion.
• Asia and West Africa hold the highest concentration of critically endangered monkeys.
• Some species have been rediscovered decades after being presumed extinct.
• Recovery is possible but requires sustained protection over decades.

The rarest monkeys in the world

Tonkin snub-nosed monkey — Vietnam

Perhaps 200 to 250 animals in fragmented limestone forest in northern Vietnam. Rediscovered in 1989 after being feared extinct. Distinctive pale blue face and thick pink lips.

Myanmar snub-nosed monkey

Described only in 2010 and already critically endangered, with a few hundred individuals in the mountains of northern Myanmar and adjacent China.

Roloway monkey — Ghana and Ivory Coast

One of Africa’s most threatened primates, with only a few isolated populations remaining after severe hunting and forest clearance.

Cotton-top tamarin — Colombia

Restricted to a small area of northwest Colombia with fewer than about 7,000 remaining. See Tamarin Monkey Guide.

Niger Delta red colobus — Nigeria

Confined to a small stretch of swamp forest under intense pressure from oil infrastructure and hunting.

Ka’apor capuchin — Brazil

A critically endangered Amazonian capuchin known from a shrinking area of eastern Amazonia.

Hainan black crested and Cat Ba langur

The Cat Ba langur, endemic to a single Vietnamese island, fell to around 50 animals before protection began; numbers have since crept upward.

Sclater’s guenon and the drill

Both Nigerian and Cameroonian specialities, heavily affected by bushmeat hunting. The drill is one of Africa’s most endangered primates.

What makes a monkey rare

Factor	Effect
Small natural range	Any local damage affects the entire species
Island or limestone endemism	No possibility of dispersal to new habitat
Slow reproduction	Recovery takes decades even under protection
Large body size	Preferred target for hunters
Specialised diet	Cannot survive in degraded or secondary forest
Proximity to expanding agriculture	Habitat converted faster than species can shift

Rediscoveries

Rarity is not always terminal. The black lion tamarin was presumed extinct until 1970, the Tonkin snub-nosed monkey until 1989, and Miller’s grizzled langur was rephotographed in Borneo after decades without records. Each rediscovery bought time — and in the tamarin’s case, a genuine recovery. See Success Stories in Monkey Conservation.

What these species need

The requirements are consistent: legally secure habitat, connectivity between fragments, real anti-poaching enforcement, and community benefit from protection. See How to Protect Monkey Habitats and Illegal Wildlife Trade.

Frequently asked questions

What is the rarest monkey in the world?

The Tonkin snub-nosed monkey is among the strongest candidates, with roughly 200 to 250 individuals remaining.

Why are so many Asian monkeys endangered?

High human population density, rapid agricultural expansion, and hunting for meat and traditional medicine.

Can rare monkeys recover?

Yes, with decades of sustained protection. The golden lion tamarin is the clearest example.

Have any monkey species gone extinct recently?

Several are considered possibly extinct, including Miss Waldron’s red colobus, last confirmed in the 1970s.

How do scientists count rare monkeys?

Line transect surveys, camera traps, acoustic monitoring and increasingly environmental DNA — see How Scientists Study Monkeys.

Related: Endangered Monkey Species, Monkey Conservation, Ultimate Guide to Monkeys.