Lazy? Koalas Are Just Chilling Out

As a means of keeping cool, koala bears hug tree trunks, which can be up to 5°C cooler than the air during hot weather.

AsianScientist (Jun 6, 2014) – Thermal imaging has revealed that koalas (Phascolarctos cinereus) cope with extreme heat by resting against cooler tree trunks. This research has been published in the journal Biology Letters.

University of Melbourne researchers observed the behaviour of 30 Koalas during hot weather at French Island, to the city’s east. They found that while panting and licking their fur helps koalas cool down, this can also lead to dehydration.

Lead researcher Natalie Briscoe, from the University’s School of Botany, said koalas were observed hugging cool tree trunks.

“We found trunks of some tree species can be over 5°C cooler than the air during hot weather,” she said. “Access to these trees can save about half the water a koala would need to keep cool on a hot day. This significantly reduces the amount of heat stress for koalas.”

Researchers used a portable weather station on a long pole to measure what the koalas were experiencing in the places they chose to sit compared to the places available to them.

Co-author Dr. Michael Kearney said that the findings were important as climate change is bringing about more extreme weather.

“When we took the heat imagery it dramatically confirmed our idea that ‘tree hugging’ was an important cooling behaviour in extreme heat. Cool tree trunks are likely to be an important microhabitat during hot weather for other tree dwelling species including primates, leopards, birds and invertebrates.

“The availability of cooler trees should be considered when assessing habitat suitability under current and future climate scenarios.”

The findings explain why heat wave events can hit koala populations hard, said study collaborator Professor Andrew Krockenberger, from James Cook University,

“About a quarter of the koalas in one population died during a heat-wave of 2009, so understanding the types of factors that can make some populations more resilient is important.”

The article can be found at: Briscoe et al. (2014) Tree-Hugging Koalas Demonstrate a Novel Thermoregulatory Mechanism for Arboreal Mammals.

—–

Source: University of Melbourne.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist