Love songs lead scientists to new populations of Skywalker gibbons discovered in Myanmar

Pairs of Skywalker gibbons wake up each morning and sing together, their voices echoing through the forest canopy of their home. The primate’s endearing love song has helped scientists confirm what was once a strong hunch: Myanmar has the largest population of endangered Skywalker gibbons on Earth.

When Star Wars enthusiast scientists identified Skywalker gibbons as a distinct species in 2017, there were fewer than 200 individuals, all located in southwest China. A study published today in the International Journal of Primatology is the first in the last century to confirm the presence of living Skywalker gibbons in Myanmar.

The study was led by the Karen C. Drayer Wildlife Health Center at the University of California, Davis, which facilitated the formation of the Myanmar Skywalker Gibbon Conservation Committee. Led by Myanmar investigators and comprised of Myanmar non-governmental organizations, the group was tasked with leading these important discoveries in their country. Field expeditions were led by partner organizations including Nature Conservation Society Myanmar and Fauna & Flora International–Myanmar.

“We were able to genetically identify 44 new groups of Skywalker gibbons in Myanmar,” said lead author Tierra Smiley Evans, a research professor in the One Health Institute at the UC Davis School of Veterinary Medicine. “This is a huge resource and success story for Myanmar.”

The exact number of individuals is unknown, but Skywalkers have been identified in areas previously thought to be occupied by the eastern hoolock gibbon. Population estimates from 2013 suggest that there could have been as many as 65,000 gibbons in the area where the Skywalkers have now been identified, making it the largest probable population of Skywalker gibbons in a single location.

Scientists suspect current numbers are lower due to continued hunting, limited protected areas and political unrest in Myanmar.

Love songs and chewed plants

Like their Jedi namesake, Skywalker gibbons cannot swim, which is why rivers tend to mark the boundaries of their species. This led scientists to believe that the Skywalkers probably extended as far as Myanmar between two rivers in the west and another in the east, but their theory was not confirmed until this study.

Security concerns related to civil and ethnic unrest, coupled with a global pandemic, have limited primate studies in Myanmar, particularly by foreign scientists. Smiley Evans said the study was only possible thanks to the efforts of the Myanmar field research team.

Between December 2021 and March 2023, the field team in Myanmar set up acoustic monitoring systems, listening to the Skywalker gibbons’ love songs every morning, recording their solos and duets, their start and end times.

Using a non-invasive DNA sampling technique created by Smiley Evans, they then collected plants and fruits chewed from the gibbons. Genetic analysis of these samples confirmed the species.

The team examined photographs to look for features that distinguish Skywalker hoolock gibbons from other hoolock species. These include thinner eyebrows, a black or brown beard instead of a white one, and incomplete white rings in females.

They also conducted threat assessment surveys in 12 villages to gather local knowledge about gibbons and the threats they face.

“Biologists did not believe that Skywalker gibbons could live in the small remaining patches in southern Shan State before starting this project,” said Pyae Phyo Aung, executive director of the Nature Conservation Society Myanmar. “I am delighted with our field team members who have done an excellent job, in a short time, building community confidence for further conservation actions. This area is degraded forest. It is really important for Myanmar and China to consider expanding conservation approaches. for the Skywalker gibbon in this new geographic area.

Red List Guidance

The results will help guide updates to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.

Although the findings increase population estimates for Skywalker gibbons, loss, degradation and ongoing human conflict in Myanmar continue to threaten the species, most of which live outside protected areas.

For these reasons, the authors suggest that the species retain its endangered designation on the IUCN Red List and that its habitat in Myanmar be considered for protected area status.

“We found Skywalker gibbons in two regions of Myanmar: Kachin State and as far south as Shan State, in degraded forests and at much lower altitudes than expected, showing us that they’re very adaptable,” Smiley Evans said. “There needs to be a system of protected areas that focuses on them.”