The Brazilian photographer Marcio Cabral was stripped of a prestigious Wildlife Photographer of the Year award last week after judges noticed that the anteater at the foot of a glowing termite mound in his picture looked an awful lot like the taxidermy anteater found at the entrance to the national park where he captured the shot.

If Cabral did use a stuffed creature in his photograph – a charge he strongly denies – it would be a new low for those claiming to document “wild” animals, and emblematic of a murky underbelly in the field. Among the tricks regularly used without disclosure to get magazine-worthy natural history images are the hiring of trained animals, the gluing or freezing of insects into position and the use of bait to lure subjects closer to the camera.

“There’s a lot of fakery,” says the US photographer Clay Bolt, one of the judges in this year’s Wildlife Photographer of the Year awards. Although the British Natural History Museum’s awards offer the “gold standard” for competitions, with strict criteria for ethical photography and experts in biology and digital trickery on the judging panel, this would not be the first time such a photograph was judged to be a fake.

A taxidermy anteater kept at one of the entrances of Emas national park, where Cabral’s award-winning photo was taken. Photograph: NHM

In 2010, the Spanish photographer José Luis Rodríguez was stripped of his £10,000 ($14,000) prize after judges became convinced that he had hired a tame Iberian wolf from a Madrid wildlife park to stage the image of a species rarely seen in the wild, despite Rodríguez’s strong denials. “It may be a beautiful image, but because it’s Wildlife Photographer of the Year, we want the animals to be wild,” says Bolt.

One of the most common ways to take the “wild” out of “wildlife photography” is by visiting a game farm. These facilities provide a convenient way to take closeup shots of confined animals without having to wait days to track them down in their natural habitat. At Triple “D” in Montana, for example, photographers pay between $150 and $500 for a 90-minute session with one of the farm’s “models”, which include trained Siberian tigers, grizzly bears, snow leopards, wolves and cougars.

Pictures of game farm animals, typically well fed and selected for their pleasing aesthetics, are so common that they have reshaped public expectation of how certain creatures look. “I could show you two pictures: a skinny wild cougar hiding in a cliff face in the sleet, or a game farm cougar with a few extra pounds and a beautiful glossy coat in the snow,” says the Canadian wildlife photographer Alex Strachan. “A purist would want to see the wild cougar fending for itself, but 99% of people would rather see a photo of a big healthy cougar.”

Laura Kaye, a Canadian photographer who specialises in birds, says there is nothing wrong with photographers documenting captive creatures provided they are well looked after, but they should disclose the techniques they use to capture their work. Kaye is more concerned by the baiting of certain wild animals such as owls. In early 2017, she received a tip about where she could find and photograph the elusive great grey owl. When she arrived, she was surprised to see the owl swooping down directly in front of the group of photographers. It turned out that someone had bought a box of live mice from a pet shop and, every 10 minutes or so, was throwing one of them into the snow a few metres in front of the cameras.

A great grey owl perches on top of a camera during a shoot where some photographers were using shop-bought live mice as bait. Photograph: The Afternoon Birder

“People who do this can get great closeup flight shots of the owl coming in and eating a mouse, but you don’t want predatory animals associating humans with food. You end up changing their behaviour,” she says. It also puts photographers who have the patience to document birds in the wild at a disadvantage. “It might take you a day or a week to get those photos that someone with a cooler of mice can get in five minutes,” she adds.

The consequences of fakery can be even more grim for insects, small reptiles and amphibians. “People do quite terrible things to small creatures, like putting them in the freezer [to slow their movement], supergluing them in place or attaching them to wires,” says Bolt. It is not hard to find forums offering tips on keeping spiders and earwigs in one place by surrounding them with a smear of Vicks VapoRub or temporarily immobilising dragonflies and ants by popping them in the freezer for 20 minutes.

To the untrained eye, the image that went viral in 2015 of a frog “riding” a beetle rodeo-style is eye-catching and whimsical. The photographer said his picture had been taken in a “natural but controlled environment – this shot was not prepared at all”. But for some conservationists, the image suggested cruelty: the frog is nocturnal, they pointed out, and its open mouth indicates extreme distress.

Some of the most common tweaks are done with photo-editing software: colours are enhanced, backgrounds altered (for example, removing floating debris from an underwater shot) and animals photographed separately Photoshopped into a single image. Changes made digitally are relatively easy to detect by looking at the raw files, something that the most reputable competitions and publications insist upon. “Digital images leave quite a specific record, so you can tell if a photo has been tampered with,” says Strachan.

The British wildlife photographer David Slater says that “all professional photographers are guilty in some degree”, because of the difficulty they face in making a living. “If you try for the genuine shot, you are less likely to be published. That’s why most photographers will push their own ethical boundaries.”

Slater well knows the economic challenges of the field: he is best known for capturing the infamous “monkey selfie” that became the subject of a protracted legal dispute over whether Slater, a crested black macaque or no one should hold the copyright to a self-portrait taken by an animal. While the photographs became world famous, Slater earned almost nothing, and considered turning to dog-walking when he was forced to defend himself in a copyright infringement lawsuit putatively brought by the monkey.

Bolt agrees that the increased financial pressure on the media industry has driven a market for ethically questionable images. “Budgets are super low and everyone is in a hurry to get content out,” he says, adding that only leading publications such as National Geographic have the resources to do due diligence on the provenance of images.

The photographer David Slater was falsely accused of gluing a bee to a blade of grass. Photograph: David J Slater

In addition to harming his bottom line, Slater says, fakery has also led to unwarranted suspicion of authentic photographs. When he entered a photograph of a bee sleeping on a blade of grass in the 2009 British Wildlife Photography awards, many assumed that the bee was dead and the image staged. “Even when you do genuine photographs, people don’t believe you,” he says.

David Yarrow, whose black and white pictures of animals including elephants and lions fetch between £10,000 and £60,000 (roughly $14,000 to $83,000), has no qualms about using trained wolves and cheetahs. He argues that how we perceive these manipulations depends on whether or not a picture is framed as wildlife photography or art. “I am an artist. I make pictures rather than take them,” he says. “Nothing crosses the line in the art world. You can superimpose Krakatoa erupting in the background and Darth Vader coming over the hill.”

Yarrow suggests that a shift in career might even be lucrative for Cabral: “That photo is now worth probably more as a piece of art.”