Gibbons are just like us, but can they catch COVID?

Jessica Williams’ home for months at a time was a wooden shack by a river with no running water or toilet, in as remote a place as it’s possible to find. 

Cut off from any form of civilisation in the vast wilderness of Cambodia’s Veun Sai-Siem Pang National Park, Williams was observing wild gibbons for her PhD. 

The park is one of the few remaining places on Earth where gibbons live in the wild. She’s trying to find out how these small apes are affected by the presence of tourists. No one anywhere in the world has studied this before. Williams made some startling discoveries. 

Rising in pitch dark before 4.30am, she would prepare for a full day in the forest. 

“My guides and I would walk about 40 minutes out from the shack to this big open grass plain and we’d sit on the edge of the forest and wait for the gibbons to start calling,” Williams says. 

“This was my favourite part of the day. The sun would be rising, and you’d start hearing the gibbon groups singing. They’re really doing this to establish their territory. 

“Gibbons are monogamous like humans; they mate for life. So, a mated pair will sing a duet together signalling that they are a strong couple, and this is their patch. 

“The song doesn’t sound like anything you’d imagine; it’s more like an ambulance siren going off and it tells other groups if they try to come in, they’ll be fought off. They’re essentially saying, ‘don’t even bother to waste your energy and time encroaching into our territory’.” 

When Williams and her co-researchers heard a group calling, they sprinted through the forest to reach them. 

“Once we found them, we’d spend all day observing them, following them and noting down their behaviour,” Williams says. 

“We did this just on our own and then repeated the exercise when groups of tourists were taken into the forest to visit the gibbons.” 

She found the gibbons significantly alter their behaviour, to their own detriment, when tourists are present. 

Instead of resting and socialising, gibbons spend more time on the lookout for danger and displaying stress and anxiety behaviours when tourist groups followed them. 

“Animals monitor their environment and detect danger by scanning the landscape,” Williams says. “When tourists were present, we found they spent much more time scanning. 

“This was coupled with a decrease in time spent resting, which is essential for maintaining normal brain function and immune responses. 

“If the gibbons’ immune system is affected it can have negative side-effects. It can shorten their life or make them more susceptible to catching diseases – and because we’re all primates, they may be able to catch something from us.” 

Williams says due to a lack of research, we don’t know for sure if the small apes, like gibbons and siamangs, can catch COVID-19 from humans. 

“These animals are so unique they need our protection.”

Jessica Williams

But disease transmission from and to humans is well documented in the great apes like gorillas and chimpanzees. 

“Having reduced immunity in the face of large and frequently changing groups of people could be detrimental to the gibbons and once a disease has been transmitted it spreads through the entire population, so we can’t take any chances,” Williams says. 

Williams thinks it’s the strong bond between our ancestors and other primates that keeps tourists travelling to such remote areas to observe gibbons. 

“There were definitely times when I could relate to what they were doing and feeling. They’re just like humans, but in trees,” Williams says. 

“They’re just as clever, they like snacks as much as we do, and value family as much as we do; they just express it differently. But then you’d see the little ones go up to their mums and they’d hug each other!”  

She says tourism did halt with the first COVID lockdowns but tour operators in Cambodia and China are now gearing up to resume visits. She is urging caution as tourism picks up again.      

“We’re not against nature-based tourism, in fact we know it can create jobs and revenue and has the potential to combat destructive practices like logging or poaching,” Williams says.   

“We also know these programs were set to boom in Asia and so before things resume and expand, we want to make sure nature-based programs are better designed to prioritise the welfare of the animals.”  

For Williams that means carrying out temperature and health checks on tourists before they enter the forests and ensuring they wear PPE masks. She also recommends limiting visits to once a day, with small numbers and only when the gibbons are naturally active.   

These recommendations – the first ever designed for gibbons globally – have been adopted as international best practice.   

“We want the tour operators to pause and reset expectations for tourism and visitors by re-designing their programs based on this new research,” Williams says.     

“These animals are so unique they need our protection. The gibbons are just like us, but with longer arms.” 

Jessica Williams studied northern yellow-cheeked crested gibbons (Nomascus annamensis) at Veun Sai-Siem Pang National Park in Cambodia and Skywalker gibbons (Hoolock tianxing) at Mt Gaoligong National Nature Reserve in China. Her research published in Animal Biology has become the world’s first guidelines to protect wild gibbons used in tourism and appears in the Journal of Sustainable Tourism.