We have long considered Asia’s only great ape—the round-bellied, long-armed, rusty-red orangutan—to be one of humankind’s closest relatives. These arboreal primates share 97 percent of our DNA and display remarkable cognitive abilities, including logic, reasoning, and tool use. High above the forest floor, this female Bornean orangutan (Pongo pygmaeus) gazes skyward, seemingly assessing the falling rain in Tanjung Puting National Park on the island of Borneo, Indonesia. Clutching a batch of leaves over her head as a makeshift umbrella, she cleverly provides some dry relief for the baby nestled against her chest. Like other orangutan mother-offspring pairs, this duo will spend nearly a decade together—the longest parental investment of any non-human animal on Earth. During this time, the mother will teach the baby how to climb, eat, sleep and travel through the canopy at great heights. Orangutans typically build a new nest each night, sometimes as high as 35 meters (115 feet) above the forest floor, and rarely descend to the ground. Referred to by the indigenous Malay people as orang hutan, which translates to “person of the forest,” orangutans are well adapted to their life aloft and do their part to help the rainforest ecosystem thrive. Through their highly varied diet, which includes fruits, leaves, and shoots from more than 500 plant species, orangutans play a central role in seed dispersal and maintaining vital forest diversity.

Despite this natural stewardship, the endangered Bornean orangutan and its subspecies counterpart—the critically endangered Sumatran orangutan—face a myriad of threats to their arboreal homes, from unsustainable logging, mining, and hunting to the rampant clearing of forests for oil-palm agriculture. Over the past two decades, Bornean orangutan habitat has been reduced by 50 percent, and the subspecies’ population has been cut in half as a result. Faced with declining numbers of orangutans and other tropical forest dwellers like rhinos and tigers, government agencies and NGOs have recently come together to create certification standards for the sustainable harvest of palm oil—the most widely used plant oil on the planet—in a concerted effort to curb the deforestation caused by this rapidly expanding industry.

Tanjung Puting National Park, Borneo

Thomas Marent

Thomas Marent is a professional wildlife and nature photographer based in Switzerland. Marent became passionate about photography with the purchase of his first camera when he was 16. He first ventured into the rainforest in Australia when he was 23 and has channeled his passion toward documenting the creatures of these unique ecosystems around the world ever since. He published the popular book “Rainforest” in 2006. It has since been translated into 15 languages. His latest book project will feature the world’s rainforest primates.

Katie Jewett

Katie Jewett

Katie Jewett is a science writer, producer, and communications manager at the Stanford Center for Ocean Solutions where she loves learning something new every day about our planet. Previously, she spent winters in the Colorado Rockies and summers living and working on the water.

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