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Sumatran orangutan population numbers were wrong in last survey

A landmark survey conducted by researchers from Liverpool John Moores University in the UK shows that the critically endangered Sumatran orangutans’ are still in threat from human activities, and also revealed that the number of these orangutans living is more than double than previously estimated.sumatran-orangutans

The lead author of the study, Serge Wich from the Liverpool John Moores University, said, “The chance that there will be zero [Sumatran orangutans] in the near future is certainly less now.” Serge Wich and his team estimated in 2008 that only 6,600 Sumatran orangutans live in the wild, but now their new survey estimated about 14,600 orangutans are living in the wild.

Although poaching and illegal pet trade are affecting the population of these critically endangered species, the loss of forest habitat is said to be the biggest threat faced by Sumatran orangutans. Indonesian forests are being continuously burnt illegally by lighting fires on the forest to help converting them to build more palm oil plantations. In this process, some of the remaining habitat of Sumatran orangutans also being destroyed.

In 2008, Wich and his team’s survey suggested that these orangutans’ population had dropped by 80% in the past 75 years. Pointing on that statement, Wich said, the new study estimates would not significantly affect that claim. Because of rapid deforestations in Indonesia’s Sumatra island in the past decades and the population of orangutans will still have declined [about] that much, albeit a bit less.

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Actually, it’s not a good news at all. Researchers claim that in their previous study, they haven’t looked every places where these orangutans lived. In the new survey, the team has had a close look at all those places where Sumatran orangutans live in Indonesia. This includes the regions of Sumatra around 1500m above sea level. Previously, they assumed no orangutans live above 900m of sea level. In their previously logged locations, researchers have found some Sumatran orangutan population has seen a minor improvements.

According to the survey report published in journal Science Advances,  the authors have “drastically underestimated” the animals’ range for the estimate, now estimated as 2.56 times as big as previously thought. They have also noted that with more orangutans alive in these regions, there would be more loss of lives because of the current deforestation trends on the island. Researchers estimate there would be a loss of around 4,500 orangutans by 2030.

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But Wich warned that protecting Sumatran orangutans was not just a matter of avoiding extinction of the whole species. He said:

“Not all orangutans are the same. What we have discovered in orangutans, similarly as in chimpanzees and other great apes, is there are these differences between populations: different rich cultures of different vocalizations, different tool use and other behaviors. If we lose the orangutans in the peat swamp areas, say, then we lose most of the tool use cultures in orangutans in Sumatra.”

Moreover, the discovery of more Sumatran orangutans in the high altitude regions has impacted the studies on these species. The new survey has opened up furthermore to find the difference in eating habits and lifestyle between these high altitude orangutans and the ones which were discovered earlier.

Orangutans had a different diet during the first observation, eating trees not consumed by orangutans in low altitude regions. And they used tools differently too, Wich said. “There’s some unique cultural behaviors.” Meanwhile, the changes in the new population estimate will not affect the Sumatran orangutan’s conservation status, which the International Union for Conservation of Nature lists as “critically endangered.”

In Indonesia, there are strict anti-deforestation rules and regulations, still happens, even in the protected areas of Sumatra. There are regulations in Indonesia that there shouldn’t be any forest clearance when peatland areas are deeper than 3m and on slopes more than a certain steepness.

The study has also noted that the illegal deforestation often happened around the roads which pass through orangutan habitats. The authors urged that these roads should be stopped where possible.

For your information, orangutans are the only great apes that live besides humans. There are two species of orangutans live on the earth – Sumatran and Bornean. According to the earlier surveys, there are about 60,000 Bornean orangutans live on the planet. Paler, longer fur and a slightly lengthier face distinct the Sumatran orangutans from Bornean. Both of these species are the world’s largest arboreal animal, which lives most of their lifetime in the trees, swinging between one to another.

The good news is, as the new survey shows the number of these species doubled than the previous estimate, there would be more chance for the humans to attempt saving the species from the extinction. There would be more time to build up new strategies for officials.

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