And as promising as that seems, this may not be enough for survival in the face of climate change, researchers warn.
Koalas are iconic marsupials found mainly in Australia. They are well adapted to life in trees thanks to their strong prehensile claws and thick fur that protects them from both heat and cold. Speaking of temperature, researchers have now discovered that koalas can regulate their body temperature much more precisely than previously thought.
Highest and lowest body temperature ever measured
In a recent study researchers studied a group of koalas for two weeks during the hottest period of 2019. And it turns out: on the hottest day of the study, when it was 40.8 degrees Celsius, the koalas also reached a body temperature of 40.8 degrees Celsius. And that is special, because this is the highest temperature ever measured in these animals. Remarkably, the lowest temperature ever measured in a koala was recorded that same morning: 32.4 degrees Celsius. For your imaging, koalas typically have a body temperature of around 36.3 degrees Celsius. This indicates that this endangered species regulates its body temperature on a much larger scale than previously thought.
To predict
These findings mean that koalas can somehow predict whether it will be a warm day. They then adjust their body temperature accordingly, lowering it significantly during cooler morning hours. “This strongly suggests that koalas predict the warmest days based on morning conditions,” suspects study leader Valentina Mella. “We’ve never seen this in koalas before.”
Coherence
The results indicate that air temperature and koala body temperature are closely related. On hot days, koalas employ a clever strategy by initially lowering their body temperature. This allows them to increase their body heat in accordance with the ambient temperature. This means that koalas do not need all kinds of cooling techniques to maintain a normal body temperature, like humans. “What surprised us was that koalas fluctuate their body temperature with changes in the environment,” says researcher Mella. “This appears to be a possible adaptive strategy to reduce the need for evaporative cooling, saving an estimated 18 percent of water.”
Regulate temperature
Koalas regulate their body temperature in different ways. For example, they use their thick fur for insulation, produce concentrated urine to save water and have a low metabolism, which means they generate less heat. They also pant and lick their fur to promote evaporative cooling. They also seek out cooler places and may press up against trees to exchange heat with cooler surfaces. Additionally, in a previous study, the same researchers observed koalas drinking water on very hot days, something that had never been seen before. But it seems that self-regulation of body temperature plays an even greater role in surviving hot days.
Climate change
You might think that in light of climate change, this is good news. Because if temperatures increase further in the future, the koala could adapt. However? Researchers aren’t so sure. “With increasing temperatures due to climate change, koalas’ survival strategy may become risky,” Mella warns. “Temperatures above 40 degrees can be fatal for mammals such as koalas.”
Temperature limit
Overall, researchers have shown that koalas have a remarkable ability to predict and adapt to weather conditions. But this ability, if global warming continues, could ultimately work against them too. The future of these animals therefore remains uncertain. “Global climate models predict that dry, hot weather conditions will worsen,” says Mella. “Periods of drought will also increase in frequency, duration and intensity. This will likely push koalas and other tree-dwelling mammals to their temperature limits.”
According to the researchers, it is therefore essential that we continue efforts to tackle climate change and protect and preserve koala habitats. “Our findings underline how crucial climate mitigation is to ensure the future survival of koalas,” Mella concludes.
