An intimate moment captured of a rescued gorilla in the arms of her caretaker has been chosen as the winner of the Wildlife Photographer of the Year People's Choice Award.

Pikin the lowland gorilla was going to be sold for bushmeat after being removed from her habitat, but was rescued by Ape Action Africa.

The image, by Canadian photographer Jo-Anne McArthur, was taken while Pikin was in transit to a larger sanctuary, calmly resting with her human companion, Appolinaire Ndohoudou, after waking from sedation.

Mr Ndohoudou helps rear gorillas, and was also forced from his home — like Pikin — in Chad due to civil war.

McArthur said she was thankful the picture had resonated, hoping it would inspire people, "to care a little bit more about animals".

The photo won the award from almost 50,000 entries, with four other finalists announced.

When polar bear mothers and cubs emerge from their dens in the early spring, the cubs stay close to their mothers for warmth and protection. ( Wildlife Photographer of the Year: Debra Garside )

In early spring, polar bear cubs emerge from their dens while staying close to their mothers for warmth and protection.

Canadian photographer Debra Garside had to wait six days near the den of this polar bear family in Wapusk National Park, Canada, before they finally emerged.

Despite being spring, the low temperatures provided challenging shooting conditions, with temperatures ranging from -35 degrees Celsius to -55C.

Garside said the high winds also made it near impossible to avoid frostbite.

Lakshitha was on safari in Maasai Mara National Reserve, Kenya, when he spotted an unusual sight - a lilac-breasted roller riding a zebra. ( Wildlife Photographer of the Year: Lakshitha Karunaratha )

Normally lilac-breasted rollers prefer perching high up in foliage.

But this roller spent an hour or more riding around on the back of a zebra, enjoying the occasional insect meal.

Sri Lankan photographer Lakshitha Karunarathna spotted the roller while on a safari in Maasai Mara National Reserve, Kenya.

Karunarathna said he waited for the surrounding zebras to form the perfect background before taking this tight crop.

Every year from July to late October southern humpback whales migrate north from their Antarctic feeding grounds to give birth in the warm sheltered waters off Tonga. ( Wildlife Photographer of the Year: Ray Chin )

This mother and her calf were floating peacefully in the waters around the island group of Vava'u, Tonga.

Southern humpback whales migrate there from their Antarctic feeding grounds every year, from July to late October, to give birth in the warmer waters.

When Taiwanese photographer Ray Chin spotted the pair and approached them, they swam a bit closer to have a look at him as well.

Chin took the shot while the pair were making an elegant turn.

Luciano had to climb the cecropia tree, in the protected Atlantic rainforest of southern Bahia, Brazil, to take an eye-level shot of this three-toed sloth. ( Wildlife Photographer of the Year: Luciano Candisani )

Sloths are often seen high up in the canopy of the Atlantic rainforest of southern Bahia in Brazil.

The three-toed animals like to feed on the leaves of the cecropia trees.

As such, Brazilian photographer Luciano Candisani had to climb up this tree in order to get an eye-level shot.

The Wildlife Photography of the Year exhibition is showing at the Natural History Museum in London until May 28.