Most koalas don’t survive after leaving the safety of trees

Koalas are everywhere on postcards and souvenirs. People think of them as calm animals sleeping in trees. But life isn’t simple for koalas anymore.

Their numbers keep dropping across Australia. Habitat loss, disease, and land clearing cause serious damage. Many forests are now small patches surrounded by roads and buildings.

Most people don’t realize how risky it is for koalas when they leave trees. New research now shows something alarming. Koalas spend only about ten minutes a day on the ground, but those short minutes cause almost two-thirds of all recorded koala deaths.

Koalas risk lives when leaving trees

Gabriella Sparkes, a PhD student at the University of Queensland, wanted to gain a better understanding of koala behavior.

“Koalas are mostly tree-dwelling, but due to extensive land clearing, they’re increasingly forced to travel on the ground, which puts them at serious risk of injury and death,” said Sparkes. “I wanted to better understand what koalas do during these ground movements.”

Vehicles and dogs kill most koalas while they walk on the ground. Even though this danger is known, many details about their movements remained unknown.

“We don’t yet have a clear understanding of how often koalas come down from trees, how far or fast they move, how long they stay on the ground, or what influences those decisions,” noted Sparkes.

“These are critical knowledge gaps if we want to identify high-risk areas or times and develop strategies to reduce threats during these vulnerable moments.”

Tracking koalas in their habitats

Sparkes and her team used special collars on wild koalas. These collars had GPS trackers and sensors called accelerometers.

The GPS recorded their locations every five minutes. When koalas started walking on the ground, the system switched to record every five seconds.

The sensors measured their movements in detail. They showed if a koala was walking, sitting, or climbing.

“When paired with GPS tracks, this gives us an incredibly detailed view of how koalas move through their habitat,” said Sparkes.

Koalas prefer staying in trees

The results were clear. Koalas prefer staying in trees. They sleep, eat, and rest there most of the time. The researchers were surprised by how rarely koalas use the ground.

“What surprised us was how infrequently and briefly they use the ground—just 2-3 times per night, averaging around 10 minutes in total, or less than 1% of their day,” says Ms. Sparkes.

Koalas only climb down when they need to move between trees. But when trees are far apart, ground travel becomes unavoidable.

Koalas move slowly between trees

People often think animals move quickly when they’re in danger. But this research showed that koalas don’t rush. They move slowly and pause often. They spend almost as much time sitting as they do walking.

“They spent nearly as much time sitting and pausing as they did walking, and only about 7% of their time on the ground was spent bounding,” said Sparkes.

“This may indicate that koalas are carefully assessing their environment as they move, possibly evaluating trees before selecting one to climb, or it may reflect the energetic costs of bounding.”

Koalas may need to check for safety before climbing a tree. They might also avoid fast movements to save energy.

Ways to keep koalas safe

This study, which was the first to track fine details of ground movement in wild koalas, has revealed clear risks and raised more questions. Sparkes and her team now study what makes koalas stay longer in trees.

“We’re now looking at environmental features that influence how long koalas stay in trees,” said Sparkes.

“If we can identify the kinds of trees or habitat conditions that encourage koalas to remain in trees for longer, we may be able to design or manage landscapes in ways that reduce the need for ground travel.”

The goal is to find trees that keep koalas off the ground. The researchers also wanted to see if certain habitats lower the need for risky movements.

Small changes can help koalas survive

The team hopes their research can guide better conservation work. They suggest keeping tree canopies connected and reducing the space between trees.

Simple actions like planting the right trees may help. Koalas need safer, connected habitats to avoid ground travel.

“This research is just one piece of the puzzle, but it adds an important layer to our understanding of how koalas interact with increasingly human-altered environments,” said Sparkes.

The findings will be presented at the Society for Experimental Biology Annual Conference in Antwerp, Belgium, in July.

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