09-07-2025
Koalas spend just 10 minutes a day risking their lives on the ground, tracking suggests
Koalas spend 20 hours a day sleeping, and most of the rest eating.
That means they can only squeeze 10 minutes in each day to move between trees, according to a new study.
Unfortunately, this time on the ground is the riskiest part of their day, said Gabriella Sparkes, a PhD student at the University of Queensland, who led the study.
Roughly two-thirds of koala deaths occur when they're on the ground — mostly from dog attacks and vehicle collisions.
"It's this disproportionate amount of death on the ground when we're talking about an animal that should be spending most of its time in the trees," Ms Sparkes said.
She presented the study today at the 2025 Society for Experimental Biology Annual Conference in Belgium.
Ms Sparkes and her team studied koalas around Pittsworth in Queensland, south-west of Toowoomba.
"It's a really agriculturally fragmented landscape," she said.
"You end up with tiny woodland patches, and then lots of strip vegetation along roads and along farms."
To understand how koalas spend their time, the researchers captured and fitted 10 animals with collars sporting GPS trackers and accelerometers.
Accelerometers, which measure movement and speed, are also used in pedometers and phones to track steps.
Unlike GPS trackers, they don't need satellite connections to log data, which is useful when you're studying something that loiters under trees.
This allowed the team to get much more granular data on koala movement than previous studies have allowed.
"Going through a koala's accelerometer trace, we could identify all the climb-downs and the climb-ups, and that really helped us pinpoint these ground visits," Ms Sparkes said.
The koalas had their steps tracked for an average of eight days each before the team removed their collars — although they were unable to get one back.
"The koala's out there somewhere," Ms Sparkes said.
The researchers found koalas visited the ground an average of just two or three times a day.
These visits totalled less than 1 per cent of the koala's day.
One koala embarked on a 45-minute odyssey across a field one night, but that was an exception.
Generally, the koalas kept their time on the ground very brief — roughly 4.5 minutes on average, adding up to about 10 minutes a day.
Ms Sparkes said koalas in different areas of the research site moved differently in her study, with those living in strips along roadsides and fields spending more time on the ground.
"Koalas in the wooded areas went to the ground more frequently in a night, but spent less time there," she said.
This means, unsurprisingly, that cleared areas and roadsides are more dangerous locations for koalas to live.
Karen Marsh, an ecologist at the Australian National University who wasn't involved in the study, said koalas in different areas would potentially spend different amounts of time on the ground.
"For example, feed trees might be more dispersed in open habitat such as paddocks or fragmented landscapes compared to forested areas," Dr Marsh said.
Time of year and conditions might also have an influence.
"Males might also spend more time on the ground in the breeding season when they are trying to locate females," Dr Marsh said.
Mathew Crowther, an ecologist at the University of Sydney who also wasn't involved in the research, said he was surprised to see how little time koalas in this study spent on the ground.
"Koalas have to move a lot because of their quite specialised diets," Professor Crowther said.
Koalas need to ensure they're getting enough nutrients to justify digesting the toxins in eucalyptus leaves.
"You've got to make sure when you're conserving habitat that you have enough trees for them to get to, and also enough feed trees as well," Professor Crowther said.
He said that this study, which was more detailed than previous movement research, could help to inform habitat restoration efforts.
Landscapes should be arranged so koalas don't have to spend much time on the ground, Professor Crowther said.
"Because obviously they don't want to," he said.
Dr Marsh agreed, saying that understanding koalas' ground movements could help to manage threats against them.
"For example, you may be able to strategically incorporate artificial habitat structures, such as poles, or replantings at key danger points to help them to get off the ground," she said.
