The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

Landscape second place: Denis Ferreira Netto, Brazil. “In a helicopter flight through the sea mountain range, I came across this white cloud cover, which resulted in this magnificent image that resembles the head of a dinosaur”, the photographer said. (Photo by Denis Ferreira Netto/TNC Photo Contest 2021)

3-year-old Myla Mills plays with a two day old lamb in a toy pram in her family's farmyard in Arley, Worcestershire, United Kingdom on January 28, 2023. Early lambs are produced when the ram is free to tup the ewes over winter. (Photo by Peter Lopeman/Alamy Live News)

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)

A Humboldt penguin swims in a pool during the annual stock take at ZSL London Zoo in London, Thursday, January 2, 2020. Caring for more than 500 different species, ZSL London Zoo's keepers face the challenging task of tallying up every animal large and small, every mammal, bird, reptile, fish and invertebrate at the Zoo. (Photo by Frank Augstein/AP Photo)

Grumpy Cat attends the “Grumpy Cat: A Grumpy Book” Book Event at Bookends Bookstore on October 16, 2013 in Ridgewood, New Jersey. (Photo by Michael N. Todaro/WireImage)

This family of warthogs regularly visited our campsite in the Ethiopian highlands so I set up a remote camera with a wide-angle lens to photograph them as they rummaged around for food. They just had a mud bath. (Photo by Will Burrard-Lucas/Caters News Agency)

Barny, the Harveys Brewery dog has a sniff of a pint of beer at the Great British Beer Festival, at Olympia in London, Tuesday, August 11, 2015. The five day event is organised by the Campaign for Real Ale (CAMRA), with over 900 real ales, ciders, perries and international beers on offer. (Photo by Kirsty Wigglesworth/AP Photo)