The photographer was exhausted. For four days, he had been swimming with the schoolIn 2011, research by the National Autism Society in Britain found that one in three children with autism say that the worst thing about school is being picked on. of barracudaA tropical fish which grows to up to 1.8m long. in the Pacific trying to capture them from the perfect angle. With their formation constantly changing, it seemed impossible. But at last they seemed to accept him as part of the group - and he started to imagine how one fish sees another. With one click he captured them as an explosion of silver.

This is just one of the extraordinary images entered for the Natural History MuseumA big museum in London which displays evidence of life in the past, such as dinosaurs. 's Wildlife Photographer of the Year competition. Between now and 2 February, members of the public are invited to choose between 25 shortlisted photos for the People's Choice Award.

One shows a pair of Chinese golden pheasants swapping places on a tree trunk in a snowstorm. Another immortalises a black bear cub in Alaska dozing on a mossy branch, watched by a young bald eagleA large sea eagle which is the symbol of the United States.. A third focuses on a herd of anxious elephants in South Africa closing ranks to protect their young.

The photographers have shown amazing patience and determination. Andy Skillen waited in temperatures averaging -30C by a log which he hoped a bear would use to cross the Fishing Branch River in YukonAn area of northwest Canada which was the scene of a gold rush in the 1890s.. When she finally appeared, after a fishing expedition, her wet fur had frozen into icicles. "You could hear them tinkle as she walked past," Skillen says.

Despite the challenges, there has been a boom in wildlife photo competitions. For the People's Choice Award, the organisers had to sift through 50,000 entries.

The reasons for the phenomenon are unclear, but it is likely that David Attenborough's hugely popular TV programmes are a major part of it. Lockdowns have given people more time to observe the creatures around them, and have produced wonderful pictures of animals in human settings they would not normally go near.

Anxiety about climate change has made us more aware of the species we share the planet with, the fragility of their habitats, and the importance of biodiversity. One particularly influential photo captured the final moments of the last male Northern White RhinoIt was originally named the wide rhino by Dutch settlers because of its wide mouth, but English-speaking settlers misheard this as white..

"It woke people up," says the photographer who took it, Ami Vitale. "You realise this isn't just the death of this ancient, gentle, hulking creature. That moment with just one animal is symbolic of what we're doing to this planet and every living creature on it."

Some photographers pride themselves on emphasising qualities animals have in common with humans. "With gorillas sharing 98.4% of our genetic make-up, it's more a case of photographing 'someone' than 'something'," says one of them, Nelis Wolmarans.

Steve Winter, a photographer for National Geographic, agrees. "One of my pet peeves is scientists saying: 'Don't anthropomorphiseAttribute human characteristics to something which is not human. animals'... I say 'Do.' The closer we are to animals, the more we understand that they have personalities, feelings."

Some say, yes: the most skilled photographers capture animals in situations which most humans would never otherwise see, and which add enormously to our understanding of them. Now that keeping animals in zoos is widely frowned upon, this is the best way of observing them.

Others argue that there is simply no substitute for watching animals in the wild and seeing how they interact with their environment. Photos actually take us further away from them, fooling us into thinking that we can get to know them by sitting at home looking at glossy images.