Koalas live in the trees and die on the ground, research shows

Koalas spend most of their time in trees — but are in deadly danger when they descend to the ground, new research shows.

The marsupials are an endangered species in Australia and their populations are rapidly declining due to habitat loss, fragmentation, and disease — plus further, urgent threats.

Koalas only spend around 10 minutes per day on the ground, but this ground-time is associated with two-thirds of recorded koala deaths.

“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,” says Gabriella Sparkes, a doctoral student at the university of Queensland, Australia.

She fitted the marsupials with GPS collars to look more closely at their movements. The devices recorded their location at short intervals, distinguishing between walking, climbing and resting, allowing for an unprecedentedly detailed analysis.

The marsupials typically descend from trees only two to three times per night, spending an average of just 10 minutes on the ground in total - less than 1% of their time, Sparkes says.

But an earlier study found that around two-thirds of all known koala deaths occur during this brief period — usally due to attacks by dogs or collisions with cars.

The researchers aim to use these findings to identify environmental conditions that are particularly dangerous for koalas and to develop more effective conservation strategies for the animals, which are listed as "vulnerable" on the International Union for Conservation of Nature's (IUCN) Red List.

"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," says Sparkes, suggesting continuous tree canopy connections or shorter distances between suitable trees.