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)

A rainbow forms on water from a spray machine used to suppress coal dust at the Krasnogorsky open pit coal mine, operated by Mechel PJSC, in Mezhdurechensk, Russia, on Monday, July 19, 2021. Russia’s government is betting that coal consumption will continue to rise in big Asian markets like China even as it dries up elsewhere. (Photo by Andrey Rudakov/Bloomberg)

A child is pictured with the face covered in blood during a religious procession to mark Ashura in Nabatieh, southern Lebanon on August 19, 2021. (Photo by Aziz Taher/Reuters)

Senior Buddhist monk Lobsang Tayang sits outside the Amarbayasgalant Monastery in the Baruunburen district, Selenge province, Mongolia, April 26, 2018. (Photo by Thomas Peter/Reuters)

A green rosella and a wallaby, known as a Pademelon, eye off as they drink from a water bowl put out for thirsty wild animals at a back-yard in Kayena, in northern Tasmania, 01 February 2019. Australia recorded its hottest month on record in January; it was also the hottest and driest month on record for the Australian island state of Tasmania. (Photo by Barbara Walton/EPA/EFE)

Female of pygmy hippopotamus called Malaya from Netherlands in zoo in Dvur Kralove nad Labem, Czech Republic, February 22, 2016. (Photo by David Tanecek/CTK via ZUMA Press)

A frozen public bench is seen next to a lake side due to the heavy wind conditions in Geneva February 8, 2015. (Photo by Pierre Albouy/Reuters)

An emu runs to escape an approaching wildfire as it burns near Potero, California, U.S. June 20, 2016. (Photo by Mike Blake/Reuters)