Although widely adored and studied, there remained one major mystery about an essential habit of koalas — how they drink water, which has finally been answered thanks to a new study and surprising video.
The study, published in the journal Ethology, cited 46 examples of koalas drinking rain water from tree trunks, something that previously had not been observed since such instances have to be captured in typically bad weather.
“For a long time, we thought koalas didn't need to drink much at all because they gained the majority of the water they need to survive in the gum leaves they feed on,” said Dr. Valentina Mella, the lead researcher on the University of Sydney project. “But now we have observed them licking water from tree trunks. This significantly alters our understanding of how koalas gain water in the wild. It is very exciting.”
Koalas rely on trees for their food supply and shelter, as well. In the wild they get about three quarters of their water intake from eucalyptus leaves, but also rely on smooth tree trunks after rainfalls to keep hydrated, even when the same water may be available nearby.
Dr. Mella’s data comes from observations made by citizens and independent ecologists between 2006 and 2019 mostly at the You Yangs Regional Park in Victoria and the Liverpool Plains in New South Wales.
Other observations came from Gunnedah and Mullaley, where a koala was seen drinking rain water from a tree trunk uninterrupted for 34 minutes.
The larger implication of Dr. Mella’s study is that the preservation of trees is essential for koalas to remain healthy — so is consistent rainfall. Australia is currently going through the longest dry period documented, which means koalas have had to seek artificial sources for water, like pools or fountains. They may even approach people and drink from their water bottles. Many of these instances have been documented on social media, but they are noted as a consequence of the state of the environment, rather than a new normal for the species.
Dr. Mella is currently fundraising to continue her research and also install artificial water stations for koalas in trees, so they can remain hydrated even in times of drought.
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