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The royal touch - The Duke and Duchess of Cambridge, Prince William and Catherine, meet Leuca the Koala during a visit to Taronga Zoo, in Sydney, last month. AAP/Dan Himbrechts

How many visitors can a koala bear? Not many, it seems

Everyone loves to get close to a koala. They are an Australian icon and a major ecotourism attraction. A photo with a koala is a holiday must for many overseas visitors.

But how well do these celebrity koalas cope with frequent, up-close or intense interactions from unfamiliar humans?

A study we conducted at the Animal Welfare Science Centre, University of Melbourne, showed that koalas displayed to the public are disturbed by noisy and up-close encounters with human visitors. The results are published this month in Applied Animal Behaviour Science.

The more visitors within a five-metre radius of the koalas, the more vigilance behaviour koalas displayed, which puts them in an alert state.

We also investigated the effect of noise itself: the louder the noise, the more likely koalas interrupted their normal daytime activity and adopted a vigilant posture.

Not the most active of animals

People often see koalas as nonchalant animals that do little but sleep all day. Hence, the common belief was that koalas will probably not show an outward response to humans.

Awake for a photo when koalas should be asleep. Flickr/Yun Huang Yong , CC BY

But our research showed just the contrary: people can disturb koalas. If visitors get too close to them, or if they are too loud, koalas interrupt their normal activity.

In some cases, this is probably encouraging for visitors: it makes for a much better picture when the koala is looking at you, right?

Why does increased vigilance in koalas matter? Vigilance is quite a normal behaviour. Remaining alert to their surroundings allow animals to detect threat, and decide how to act appropriately.

But problems occur when that alert response is triggered too often, which can result in chronic stress. Vigilance is usually linked to the fight-or-flight response, one of the main mechanisms of the stress response.

This stress response is often an energy-costly mechanism too. This may be a more serious issue for koalas than for other species, since koalas have evolved on an extremely low energy diet of eucalyptus leaves, so minimise energy expenditure by sleeping 18 to 20 hours a day.

In fact, in this study, the koalas spent half as much time vigilant as they spent looking for food. Hence, this higher time spent vigilant may come at the cost of less time left to forage.

Not enough energy is a problem

These results provided interesting practical knowledge for the Koala Conservation Centre, at Phillip Island, Victoria, with whom we worked. Recording koala behaviour proved to be a valuable, non-invasive monitoring tool to assess visitor-related disturbance in captive koalas.

Watching the koalas at the Koala Conservation Centre. Flickr/Jonathan Lin, CC BY-ND

This means the rangers can act to try to reduce disturbances as much as possible by adopting different visitor management strategies.

This study is only a first step into a complex topic. Further research is needed to determine whether those frequent disturbances actually impact koala welfare. It may, or it may not, but science-based knowledge is required in the field of animal welfare science.

Other factors may also need to be considered, such as previous experiences and the way animals are raised.

Koalas on public display

Some studies on this so-called “visitor effect” raise an ethical dilemma for establishments that display animals to the public. A balance needs to be achieved between visitor experience and education on one hand and animal welfare on the other. Other studies suggest a positive effect on animal welfare from such human encounters.

Even in captivity a koala needs to sleep much of the day. Flickr/Kim, CC BY-NC-SA

Our study was done in semi-captive settings, with koalas able to roam freely in large boardwalk enclosures.

Some wildlife parks allow hands-on experiences with koalas. The impact of these practises on the koalas’ behaviour and welfare has not been scientifically assessed, but it does remain a crucial question if we aim to protect our must-see native fauna.

In the meantime, the best attitude may be to keep a distance with this wonderful animal, so that both parties can continue to enjoy living together in a sustainable way.

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