( On July 26, a Simeulue long-tailed macaque forages in a tree on Simeulue Island, Indonesia. /CFP)

In the forests of Indonesia’s Simeulue Island, a critically endangered Simeulue long-tailed macaque climbs through the trees. This species, found only on the island off the west coast of Sumatra, is among the world’s most endangered primates.

( On July 26, a Simeulue long-tailed macaque climbs down a coconut tree on Simeulue Island, Indonesia. /CFP)

According to the IUCN Red List, the Simeulue long-tailed macaque is currently classified as “Critically Endangered,” with its population estimated to have declined by at least 95% over the past three generations. Surveys show that their numbers have sharply dropped from around 50,000 to fewer than 250, although scientists believe that about 1,000 individuals may still exist.

The sharp decline is driven by deforestation, agricultural expansion, and human-wildlife conflict, as the monkeys are often seen as pests for raiding crops. In response, an international nonprofit launched a conservation project on Simeulue Island in 2021.

( On July 24, volunteers from the conservation project for the long-tailed macaques on Simeulue Island tell stories about the species to students at a local elementary school. /CFP)

The group works to protect the species by studying macaque behavior, raising public awareness, and collaborating with local communities to promote coexistence. Similar efforts are underway in Malaysia, the Philippines, Cambodia, India, and Bangladesh to protect macaques and their subspecies across South and Southeast Asia.

Now on the brink of extinction, the Simeulue macaques are fighting to hold on to their last remaining habitat.