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)

Japanese macaques, also known as snow monkeys, play as they soak in a hot spring in Jigokudani valley in Nagano Prefecture, northwest of Tokyo Saturday, March 6, 2021. (Photo by Kiichiro Sato/AP Photo)

A squirrel fights for its life in the bill of a great blue heron at the Mission Trails Regional Park in California in the second decade of April 2025. (Phoot by Decker Nomura/Solent News & Photo Agency)

People visit a frozen waterfall illuminated by colorful lights at Dadunxia sceneic area on December 25, 2022 in Linxia Hui Autonomous Prefecture, Gansu Province of China. (Photo by Shi Youdong/VCG via Getty Images)

A palm squirrel and ring-rosed parakeet compete for space on a stump in a residential area of Chandigarh, India in the last decade of August 2024. (Photo by Anuj Jain/Solent News)

(L-R) Madelaine Petsch, Julia Fox, Kacey Musgraves, Kim Petras and Aquaria attend the Moschino Prefall 2020 Runway Show front row at New York Transit Museum on December 09, 2019 in Brooklyn City. (Photo by Astrid Stawiarz/Getty Images for Moschino)

A Tibetan living-in-exile in India attends a peace march during the 62nd Tibetan National Uprising Day in the suburb of McLeod Ganj, the seat of the Central Tibetan Administration in exile, near Dharamsala, India, 10 March 2021. Tibetan Uprising Day is held annually on 10 March and commemorates the Tibetan uprising against the presence of the People's Republic of China in Tibet in 1959. (Photo by Sanjay Baid/EPA/EFE)

A woman, covered in coloured powder, takes part in the 2019 Colour Run, a 5 km run around the Luzhniki Olympic Complex, in Moscow, Russia on June 02, 2019. (Photo by Sefa Karacan/Anadolu Agency/Getty Images)