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)

Romanian female soldiers stand prior to the military parade on Romania's National Day in Bucharest, on December 1, 2022. (Photo by Daniel Mihailescu/AFP Photo)

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 fox stands along a street in the Central London, Wednesday, March. 1, 2023. (Photo by Kin Cheung/AP Photo)

Policemen guard Poland's Supreme Court as a protester lies on the pavement in Warsaw, Poland, on Thursday, April 22, 2021. A disputed disciplinary body within Poland's Supreme Court is examining a motion that could result in the arrest of a judge who has become a symbol of the fight for an independent judiciary. (Photo by Czarek Sokolowski/AP Photo)

A couple dance by the Golden Horn leading to the Bosphorus Strait separating Europe and Asia, in Istanbul, Friday, May 14, 2021. (Photo by Emrah Gurel/AP Photo)

A jogger is seen running at Hampstead Heath with London in the background on June 1, 2021. Britain sees temperatures increasing for the second day in a row after the mercury hit 25C (77 Fahrenheit) for the warmest day of the year so far on Bank Holiday Monday. (Photo by Joshua Bratt/London News Pictures)

Coronavirus vaccinated audience members watch Saudi prominent singer Mohammed Abdu as he performs at the newly built Super Dome, in Jiddah, Saudi Arabia, late Thursday, July 8, 2021. The concert is organized by the Saudi General Entertainment Authority after the kingdom lifted coronavirus restrictions on events in May. (Photo by Amr Nabil/AP Photo)