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)

Participants take part in the annual New Year' s Day Parade in central London, United Kingdom on January 1, 2018. Reports state that 8,000 performers representing the London boroughs and countries from across the globe are parading along the streets of London's West End on New Year’s Day. (Photo by Tolga Akmen/AFP Photo)

Residents recently returning to their area cleared by government troops react as they ride a tricycle a day after President Rodrigo Duterte declared the liberation of Marawi city in southern Philippines Wednesday, October 18, 2017. Sporadic explosions continue Wednesday as Philippine soldiers fought to gain control of the last pocket of Marawi controlled by Islamic militants. (Photo by Bullit Marquez/AP Photo)

Workers tend green onion plants among nearly 1,000 acres of terracing in fields in the Majalengka Regency of West Java in Indonesia in July 2021. (Photo by Andika Oky Arisandi/Solent News)

Artists dressed as Hindu gods reacts to the camera during the Bonalu festival procession in Secunderabad, the twin city of Hyderabad, on July 26, 2021. (Photo by Noah Seelam/AFP Photo)

Nigerian make-up artist, Mary Oni, creates artwork on her chest using make-up, in her home in Lagos, Nigeria on January 26, 2022. (Photo by Seun Sanni/Reuters)

Security chase a spectator on centre court during a rain delay on Day Two of the National Bank Open presented by Rogers at IGA Stadium on August 10, 2021 in Montreal, Canada. (Photo by Minas Panagiotakis/Getty Images)

Anti government protesters splash water on each other as they celebrate the traditional Songkran new year festival during a protest in Bangkok, Thailand, 13 April 2022. (Photo by Diego Azubel/EPA/EFE)