A UCalgary primatologist says human activities threaten the already Critically Endangered Javan slow loris and explains how they might use sleep to adapt to climate change.
By Avrille Aiello
The Javan slow loris, an odd little nocturnal primate, wakes up from a long sleep around sunset and begins its day exploring the Indonesian forests and foraging for plant gum, nectar and insects. These venomous Southeast Asian tree dwellers are among the most peculiar of primate species.
Slow lorises on the island of Java are currently facing many challenges, including climate change, habitat encroachment, and the illegal animal trade. Dr. Kathleen Reinhardt, an instructor at the University of Calgary, has been studying a wild population of the Critically Endangered Javan slow loris.
Changing environments
Slow lorises are forced to live at higher altitudes because human agricultural practices are expanding on Java. Reinhardt says, “it’s a combination of population growth and climate change” that drives the expansion of farms into areas that are not traditionally used.
First, everything on Java is being pushed to higher elevations because the cities below are expanding rapidly. Second, Reinhardt explains, “every 100m, the temperature variation can drop by one degree Celsius. By moving up to higher elevations, you can avoid some of the more extreme heat.” While the farmers adapt to climate change by moving to cooler areas for their crops, lorises are exposed to more extreme daily temperature fluctuations at higher elevations.
Climate and temperature are highly integrated with the lives of lorises. Critically, their main food sources are impacted by fluctuations in temperature. Reinhardt indicates that these changes affect the growth cycles of food-producing plants and how their prey insects fly.
A 2016 study by Reinhardt and colleagues found that Javan lorises living at higher altitudes spend more time travelling and foraging and less time resting than other groups. The slowed development of food resources at colder temperatures forces the animals to actively look for food and spend more time travelling between food patches. Reinhardt says that the lorises are spending more time and energy at night acquiring the same amount of food that they could get at lower altitudes.
After a hard day’s night
The Javan loris researchers found that these primates are using torpor, a period of inactivity like hibernation. Reinhardt says, “torpor is largely influenced by food availability and temperature.” This population of slow lorises may be using it as a strategy to cope with the costly demands of living in conditions of cold and food scarcity.
The phenomenon of torpor use was not studied in this species previously. And as this revelation was recent, Reinhardt mentions that we do not know if lorises have always used torpor or if we are just learning about it now. However, it’s hypothesized that more and more animals are using torpor to respond to increasing stressors in their habitats.
“Who wants a venomous pet, anyways?”
Distressingly, a major threat to wild loris populations is the illegal animal trade. Although these creatures are extremely adorable, with their wide eyes and fuzzy fur, they are assuredly a regrettable companion. Not only are they active during the night, but they are also poisonous and rather smelly.
“Because of the illegal wildlife trade, you get a lot of confiscations,” says Reinhardt. “When you want to reintroduce them, you want to know what habitat they can actually go into.” According to Reinhardt, reintroductions have been unsuccessful in the past because researchers did not know what habitats are most suitable for lorises. Reinhardt mentions that studying the adaptations of the animals and knowing what areas they can handle helps conservationists understand the best reintroduction and relocation areas.
Looking forward
What does the future of the Javan slow loris look like? Reinhardt says it is hard to say, but their population health in 10 years will depend on humans. Habitat loss, encroachment by humans, the wildlife trade, and climate change caused by humans are things that need to be addressed to keep these endangered animals alive.
There is still optimism among loris researchers. “For a species that is so specific in their ecological niche, they are surprisingly adaptive.” Reinhardt ends by noting that the use of torpor demonstrates an ability to adapt to ecological extremes, which could be a positive indication for the future of lorises.