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)

Darth Vader balloon above Clifton Suspension Bridge during the hot air balloons mass ascent at sunrise on the first day of the Bristol International Balloon Fiesta on August 8, 2019 in Bristol, England. The Bristol International Balloon Fiesta is Europe's largest annual meeting of hot air balloons, attracting over 130 hot air balloons from across the globe. (Photo by Finnbarr Webster/Getty Images)

A fisherman waits to catch fish as he sits atop a stilt in the sea in Koggala, Sri Lanka on July 4, 2019. (Photo by Dinuka Liyanawatte/Reuters)

Iraqi Kurdish women work at a hand-weaving Kurdish traditional carpet shop, in the district of Raniya, about 70 kilometres (43 miles) east of Arbil, the capital of Iraq's northern autonomous Kurdish region, on February 11, 2025. (Photo by Safin Hamid/AFP Photo)

One of the Siberian tiger twins, born on April 13, 2025, is presented to the press at the Budapest zoo and botanic garden, on June 12, 2025 during their first veterinary examination. (Photo by Attila Kisbenedek/AFP Photo)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

Tsetse, six-year-old daughter of Dukha herder Erdenebat Chuluu, sits among her family's reindeer in a forest near the village of Tsagaannuur, Khovsgol aimag, Mongolia, April 21, 2018. Nyamaa is an ethnic Darkhad, herders of northern Mongolia who have historically inhabited the steppe that borders the Taiga forests. (Photo by Thomas Peter/Reuters)

Students of the Ballet Academy prepare to perform during the school annual ceremony in Baghdad, Iraq, Friday, April 1, 2022. (Photo by Hadi Mizban/AP Photo)