Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)

Cambodian children sleep on a pavement at a park in Phnom Penh on July 8, 2016. (Photo by Tang Chhin Sothy/AFP Photo)

Highly commended birds : Crested guan by Tim Hunt (UK). ‘This photo shows a crested guan in the cloud forests of Costa Rica as it pauses while foraging on a lone branch. Due to the clouds that are so typical for this habitat, I could often only photograph the bird’s silhouette against a grey sky. But then, for a short moment only, the sun broke through the clouds, and I overexposed the image by over two stops in order to blow out the background and allow this beautifully marked bird to stand out’. (Photo by Tim Hunt/GDT European Wildlife Photographer of the Year 2015)

This handout picture taken on December 13, 2016 and released on December 14, 2016 by the Tiergarten Schoenbrunn zoo in Vienna, Austria, shows a baby sloth eating some salad as it hangs on it's mother's belly in their enclosure. The baby was born already on November 18, 2016, but according to the zoo it could be picured for the first time only now as it usually hides in it's mother's soft coat. (Photo by Daniel Zupanc/AFP Photo)

Migrant children play with leaves during Christmas Eve at a shelter, as they travel with their parents as part of a caravan with humanitarian visas to transit throughout the country, in Monterrey, Mexico on December 24, 2021. (Photo by Daniel Becerril/Reuters)

A wrestling camel adorned with colourful ornaments takes part in the Camel Beauty Contest ahead of the annual 40th Efes Selcuk Camel Wrestling Festival, in the Aegean town of Selcuk, near Izmir, Turkey on January 15, 2022. (Photo by Murad Sezer/Reuters)

A devotee dressed as a Roman soldier whips a penitent playing the role of one of two thieves sentenced to be crucified alongside Jesus Christ, during the Via Crucis or Way of the Cross reenactment in the Petare neighborhood of Caracas, Venezuela, Friday, April 15, 2022. Holy Week commemorates the last week of the earthly life of Jesus Christ culminating in his crucifixion on Good Friday and his resurrection on Easter Sunday. (Photo by Matias Delacroix/AP Photo)

A Ukrainian serviceman fires with a ZU-23-2 anti-aircraft cannon at a position near a front line in the Kharkiv region, as Russia's attack on Ukraine continues, Ukraine on August 10, 2022. (Photo by Vyacheslav Madiyevskyy/Reuters)