A person shields themself from snowfall as they walk to a taxi in Midtown Manhattan, New York City on January 6, 2024. Forecasters warned on January 5 that a deluge of snow and wintery conditions could bring travel chaos to the US northeast this weekend, with some 25 million people subject to a storm warning. (Photo by Adam Gray/AFP Photo)

An alligator and his reflection seen in the Wakodahatchee Wetlands in Delray Beach, Florida on May 2, 2024. The wetlands attract nature lovers and wildlife photographers and are home to more than 140 bird species and a variety of other wildlife. (Photo by Ronen Tivony/ZUMA Press Wire/Rex Features/Shutterstock)

A walrus takes centre stage after barging another out of the way to be in a photograph in Svalbard, between mainland Norway and the North Pole in January 2025. (Photo by Olav Thokle/Syndicated Photos/Solent News)

A one-and-a-half-month-old orphaned two-toed sloth clings a sloth plush toy at the Panamerican Conservation Association (APPC) during a conservation activity for International Sloth Day, in Panama City, Panama, on October 19, 2025. (Photo by Enea Lebrun/Reuters)

An African giant pouched rat sniffs for traces of landmine explosives at APOPO's training facility in Morogoro on June 17, 2016. APOPO trains the rats to detect both tuberculosis and landmines at its facility. Every year landmines kill or maim thousands of people worldwide. The trained rats sniff for explosive and so are able to detect the presence of landmines far faster than conventional methods which involve metal detection. (Photo by Carl De Souza/AFP Photo)

Female Siberian tiger Dasha yawns in the new enclosure at the zoo in Duisburg, Germany, 30 March 2016. The new facility is three times larger than the old one and will be opened to the public on the same day. (Photo by Roland Weihrauch/EPA)

Six month- old baby elephant “Clear Sky” is kept afloat with the help of a harness during a hydrotherapy session at a local veterinary clinic in Chonburi Province on January 5, 2017. After losing part of her left foot in a snare in Thailand, baby elephant 'Clear Sky' is now learning to walk again – in water. (Photo by Roberto Schmidt/AFP Photo)

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)