South African photographer Greg du Toit has been named this year's Wildlife Photographer of the Year for his image of African elephants in Botswana.

Du Toit's picture, Essence of Elephants, was picked by a panel of experts from almost 43,000 other entries in 96 countries.

The winners were announced at a gala awards ceremony at the Natural History Museum in London, where the photograph will take centre stage in an exhibition with other images shortlisted in the competition.

Speaking about Essence of Elephants, du Toit said: "My goal was to throw caution to the wind, to abandon conventional photographic practices in an attempt to capture a unique elephant portrait. This image hints at the special energy I feel when I am with elephants."

He spent 10 years trying to capture the perfect portrait of elephants and eventually got the shot in the Northern Tuli Game Reserve in Botswana.

Jim Brandenburg, chair of the judging panel, said: "Greg's image immediately catapults us to African plains. This image stood out for both its technical excellence and the unique moment it captures - it is truly a once in a lifetime shot."

The Young Wildlife Photographer of the Year 2013 was awarded to Udayan Rao Pawar, who took the title for his image of gharial crocodiles on the banks of the the Chambal River in Madhya Pradesh, India.

Named Mother's Little Headful, the picture shows 11 crocs gathered together on top of their mother's head. The 14-year-old said he camped close to the river overnight to capture the shot.

"When dawn broke I saw this scene. The mother rose to the surface from the murky depths of the river in response to the guttural calls of hatchlings, which then rushed towards her and climbed over her exposed head," he said.

Commenting on the image, competition judge, naturalist and acclaimed wildlife photographer Tui De Roy said: "The composition and timing of Udayan's photograph is perfect. The mother's gaze seems directed at you, appealing to you to let her live and thrive in peace. This image is beautiful and thought-provoking, but at the same time also wonderfully playful, making it a clear winner."

The exhibition of the images will run at the Natural History Museum between 18 October and 23 March, after which it will go on an international tour around the globe.