As we recently reported, a survey of the wild orangutan population in Sumatra revealed that there were actually about twice as many individuals as previously thought. This prompted headlines claiming that orangutans, a critically endangered species, were on the rebound in Sumatra. Despite the survey’s findings, however, scientists still say that orangutans are in a perilous position due to a single looming threat.

That threat? Humans. Despite the total increase in the count, researchers still believe orangutans are declining in other wild populations around the world, and wouldn’t be surprised to learn that Sumatra has even lost a significant number of orangutans. According to the Orangutan Conservancy, some scientists fear that the species could even be completely wiped out in the next 25 years.

The biggest challenge orangutans face is recouping habitat loss due to human activity. Orangutans are being pushed out of their natural ranges and squeezed into places that scientists never even thought to look for them – that’s one of the biggest reasons for the census discrepancy that was recently reported.

Habitat loss occurs because of a wide range of human activities, including but not limited to deforestation, palm oil production, illegal poaching for meat and the exotic pet trade. In the past 20 years, orangutans have lost over 80 percent of their natural habitat. To make matters worse, scientists estimate that as much as one-third of the wild population died during forest fires throughout 1997 and 1998.

The WWF reports that the Sumatran orangutan once ruled the entire island, but its range has since been restricted to a few regions in the north. There are currently nine wild populations of orangutans in Sumatra, and researchers say that only seven of them are viable in the long-term. Each population has only about 250 individuals, and there are only three separate groups that have more than 1,000 individuals.

Scientists were thrilled to learn that there were more orangutans in Sumatra than previously thought, but the wondrous creatures still face considerable threats from human activities.

A news release describing the details of the recent survey can be found here.