Check out these winning images from the Wildlife Photographer of the Year 2012 competition.
Anna Henly (UK) took this image on a boat in the Svalbard archipelago early in the morning. The polar bear was walking on broken ice floes, a reminder that global warming is eroding the marine sea ice environment that the bears rely on for survival.
The turquoise tint on Peyto Lake in Banff National Park, Canada, is caused by light bouncing off silt suspended in the water, known as "glacial milk". Vladimir Medvedev (Russia) waited for an opportunity between snowfalls to overcome the challenges of light in such a pale environment.
This black-headed gull caught Eve Tucker's eye as it sat in the middle of the extraordinary patterns in the water. Eve (UK) realised these patterns were in fact the reflections of some of the tallest buildings in London surrounding the Docklands at the heart of the business and banking area of Canary Wharf.
The overall winner of the Veolia Environnement Wildlife Photographer of the Year is Paul Nicklen (Canada) for his photo 'Bubble-jetting emperors'. It was taken near the emperor penguin colony at the frozen edge of the Ross Sea, Antarctica. Paul waited for the return of parent penguins, staying still in the freezing water and using a snorkel to breathe.
Junior overall winner Owen Hearn took his image 'Flight paths' at his grandparents' farm in Bedfordshire, UK. Owen, aged 14, photographed the red kite at the site chosen for London’s third airport in the late 1960s. "Opposition to the planned airport stopped it going ahead, which is why I can photograph the wildlife on the farm today," he explained.
Thousands of Caribbean flamingos - the largest and pinkest of the five species - gather each winter on the estuary of the Ria Celestun on Mexico's Yucatan peninsula. From the door of a plane, Klaus Nigge (Germany) used lenses with image stabilisers to get an aerial shot showing the beauty of the mass get-together.
Luciano Candisani (Brazil) was the winner in the Behaviour: Cold-blooded Animals category. His image shows a yacare caiman lurking in the shallow, murky waters of Brazil's Pantanal. Organised by London's Natural History Museum (NHM) and BBC Wildlife Magazine, the competition is now in its 48th year. An exhibition of the best pictures opens this Friday at the NHM and runs until March.
Steve Winter (US) was the winner of the Wildlife Photojournalist Award. The animal is one of fewer than 400-500 wild, critically endangered Sumatran tigers. Steve set up an auto-trap camera to catch this shot. A former tiger hunter, now a park ranger, advised Steve where to set up his equipment.
Kim Wolhuter (South Africa) won the Gerald Durrell Award for Endangered Species. Kim has been filming African wild dogs at Zimbabwe's Malilangwe Wildlife Reserve for more than four years. He knows one pack intimately. "I have travelled with them, on foot, in the pack itself, running with them as they hunt."
Gregoire Bouguereau (France) won the Behaviour: Mammals category with this image of cheetah cubs chasing a Thomson's gazelle calf that their mother had caught but not killed. At first, the cubs took no notice of the calf lying on the ground. But when it struggled to its feet, "the cubs' natural predatory instincts were triggered," says Gregoire.