Two sheep fight in a competition in Zhangjiakou, Hebei province, China on August 1, 2017. (Photo by Reuters/China Stringer Network)

A woman uses protection masks to cover her face as protestors from the Million Mask March and anti lockdown protesters demonstrate, amid the coronavirus (COVID-19) outbreak in London, Britain on November 5, 2020. (Photo by Henry Nicholls/Reuters)

Two stags fight in a wildlife park in Aurach near Kitzbuehel, in the Austrian province of Tyrol. (Photo by Kerstin Joensson/Associated Press)

Firefighters use a rope to rescue a group of people stranded in a flooded street on July 12, 2018 in Chengdu, Sichuan Province of China. A strong storm has hit many parts of southwest China's Sichuan Province since Monday, causing landslides and floods in the region. (Photo by Wang Hongqiang/Chengdu Economic Daily/VCG)

Mother and son in disguise attend a Halloween celebration at Taipei Children's Amusement Park in Taipei, Taiwan, Sunday, October 29, 2023. (Photo by Chiang Ying-ying/AP Photo)

Battersea Power Station Ice Rink in London, United Kingdom on November 13, 2022. Running until 8th Jan. 2023, a large outdoor ice-rink outside the power station and next to the riverside brings in festive Christmas fun with vivid illumination. (Photo by Guy Corbishley/Alamy Live News)

People react as they ride an escalator on the London Underground during the “No Trousers Tube Ride” in London, Britain on January 7, 2024. (Photo by Hollie Adams/Reuters)

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)