Central and South America sloth populations may face a serious existential threat climate change towards the end of the century. New research published September 27 in the journal PeerJ indicates that simply from a metabolic point of view, rising global temperatures could pose a serious threat to the species’ overall health and long-term survival.
Led by Rebecca Cliffe, a zoologist and founder of Sloth Conservation Foundationexperts conducted their latest research two-toed sloths (Choloepus hoffmanni), living in both highland and lowland areas with a spectrum of average ambient temperatures. Using a methodology known as indirect calorimetry, Cliffe’s team analyzed the sloths’ oxygen consumption and core body temperatures in situations that reflected the warming rate expected for their habitats by 2100 – somewhere between 2 and 6 degrees Celsius (3.6 to 10.8 degrees Celsius). degrees Fahrenheit). According to their research, the consequences are “expected to be profound.”
(Related: Sloth schedules are surprisingly flexible.)
“Sloths are inherently limited by their slow metabolism and their unique inability to effectively regulate body temperature, unlike most mammals,” Cliffe explains in an article. accompanying statement. “Our research shows that sloths, especially in high-altitude areas, may not be able to survive the significant increases in temperatures forecast for 2100.”
The biggest problems for sloths at higher altitudes stem from a sharp increase in resting metabolic rate (RMR) when confronted with warmer temperatures. This is especially problematic given their limited metabolic adaptability and difficulty in finding cooler habitats. While low-altitude sloths may be able to move to higher altitudes to find cooler homes, in contrast they still showed a biological survival trait called ‘metabolic depression’ that limits any further increase in RMR. This alone would pose its own threat to their health.
It’s not just sloth metabolisms that are worrying. The the animal’s digestion speed can be as much as 24 times slower than similarly sized herbivores. This means they can’t simply eat more food, as both global temperatures and sloths’ metabolisms increase.
Cliffe’s team admits in the study that their climate model was “rudimentary in omitting error and uncertainty considerations.” Despite this, “they predict that a relatively small increase in ambient temperature could leave high-altitude sloths in a situation where it is impossible to match their energy consumption to their energy budget.” It is this delicate balance between metabolism, digestion and habitat temperatures that makes the slow-moving species particularly sensitive to the effects of climate change.
