Quokkas, tiny and furry internet stars, seem to grin for selfies, attracting fans from around the world to an Australian island - but what rules should visitors follow to keep them safe?
With their round faces, tiny ears, beady eyes and seemingly permanent smiles, quokkas have earned the reputation as "the happiest animals in the world."
These small marsupials, found almost exclusively on Rottnest Island off Australia's south-west coast, have become an internet sensation.
In times of global uncertainty, their irresistibly cute charm provides the perfect viral distraction.
Whether in videos or memes, the quokkas - also known as short-tailed kangaroos - have captured the hearts of people around the world with their cheerful expressions.
And yes, there is even a hashtag: #quokkaselfie. But let's be clear - they don't always smile.
Getting that perfect angle requires patience. Still, when the moment is right, their friendly grins in smartphone photos are almost impossible to resist.
The "illusion of a smile"
"While quokkas may appear to be smiling, this is actually due to their uniquely structured jaw - which gives them an illusion of smiling," explains Arvid Hogstrom, director of environment, heritage and park services at the Rottnest Island Authority.
Illusion or not, one thing is certain: quokkas are undeniably adorable. Their young, known as joeys, often peek out from their mothers' pouches, occasionally venturing out to explore the world - though never far from the safety of mum's side.
On the largely undeveloped island, with only a small number of visitor lodgings, shops and restaurants, quokkas are the undisputed stars.
It's easy to suspect that many visitors make the trip from Perth with one main purpose: to see these furry locals up close.
No natural enemies
Although the island is dotted with signs explaining how to interact responsibly with the animals, many tourists still try to nab the iconic "quokka selfie" at any cost.
Experts recommend keeping a distance of about two metres to protect the animals in the long term. But that's often easier said than done - if people don't approach the quokkas, the quokkas frequently approach them.
The marsupials are exceptionally trusting, largely because they have no natural predators on their island home.
And it's no surprise they seem so cheerful: windswept Rottnest Island is wild and beautiful, with rocky coves and white sand beaches.
Whales can sometimes be seen in the turquoise waters offshore as they continue their journey toward Antarctica, while a large seal colony near Cape Vlamingh lounges and splashes in the shallows.
Almost all guests explore the island by bike or on foot - only employees of the Rottnest Island Authority and the quokka tourist bus are on four wheels. Incidentally, the bus is emblazoned with a giant quokka - could it be any other way?
How do quokkas live?
The animals are roughly the size of a well-fed domestic cat and lead a rather cozy life: they are nocturnal and like to snooze in the shade of dense bushes during the day.
They often wake up in the early morning and late afternoon, when they hop all over the island in search of food. Grasses and leaves are on the menu - just like with their relatives, the kangaroos or wallabies.
Quokkas are sociable animals and usually live in family groups. Their life expectancy is around 10 years.
The name is believed to originate from the Noongar language, spoken by the region's Indigenous people, who also refer to the island as Wadjemup.
The better-known name, Rottnest, comes from Dutch sea captain Willem de Vlamingh, who landed on the island in December 1696. Mistaking the quokkas for unusually large rats, he named the island "Rotte nest" - meaning "rat's nest."
Tourism also has positive effects
According to estimates by the Western Australia tourism authority, around 10,000 to 12,000 quokkas live on the island.
Hogstrom says, "The quokka population varies seasonally, and year to year, due to various natural environmental conditions such as rainfall and heat."
Overall, quokkas are considered an endangered species but as controversial as the selfie boom may be, it does have some positive side effects.
"Tourism has contributed to increased awareness that quokkas are a vulnerable species, which has led to greater education about these unique animals," Hogstrom explains.
In fact, the Rottnest Island Authority is focussing on information rather than deterrence: Even on the ferry, visitors are shown a video explaining that quokkas are in need of protection.
Once on the island, signs, brochures and free guided tours explain how to encounter the animals without endangering them.
Strict rules - and high penalties
Clear rules apply: Touching and feeding are taboo. "Feeding quokkas can lead to problems with their digestive system and make them generally unwell," says Hogstrom.
Even leaves from human hands are problematic, as the animals would otherwise forget their natural foraging behaviour. Tourists should not offer water either - quokkas have learnt to draw liquid from plants.
"Touching quokkas can make them sick, spread disease - and even cause mothers to abandon their young if they carry an unfamiliar scent," he adds.
Anyone who breaks the rules must expect consequences. "Under the Rottnest Island Regulations 1988, any physical interactions with a quokka can lead to a $200 (Australian) on-the-spot infringement. It may also lead to eviction from the island," explains Hogstrom.
However, according to the expert, most visitors adhere to the guidelines and interact appropriately with the quokkas.
Fortunately, most visitors follow the guidelines and treat the animals with respect. The best way to enjoy their company is simply to observe them from a distance in their natural environment.
After all, guests are in the realm of the world's happiest animals - and it's worth keeping it that way.