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 participant Saint Nicholas parade walks from house to house dressed in the traditional devil and Nicholas costumes in Francova Lhota district of Zlin, Czech Republic on December 3, 2017. This type of parade is one of the most popular age old tradition in a few villages in Wallachia region (eastern part of Czech Republic). Saint Nicholas walks the streets going from house to house three days and Saint Nicholas gives sweets to children and the devils get up to mischief. (Photo by Lukas Kabon/Anadolu Agency/Getty Images)

Guests attend preview event for “Candytopia”, the outrageously interactive candy wonderland, opening in San Francisco, USA on September 6, 2018. (Photo by Kelly Sullivan/Getty Images for Candytopia)

Cemetery workers lift a corpse from a coffin to a metal plate as they prepare the body for cremation at a cemetery in Maracaibo, Venezuela, November 27, 2019. Some overcome the financial burden of a relative's death by renting caskets, a cheaper option than buying one. (Photo by Rodrigo Abd/AP Photo)

The body of an unidentified man lies on a road barrier near a village recently retaken by Ukrainian forces on the outskirts of Kharkiv, Ukraine, Saturday, April 30, 2022. Ukraine's second-largest city, has been under sustained Russian attack since the beginning of the war in late February. (Photo by Felipe Dana/AP Photo)

Artists and dancers perform dances during the Qhapaq Raymi (summer solstice) Festival in Cusco, Peru on December 21, 2022. Cusco is one of the most touristic cities in Peru and tries to return to normality, after two weeks of intense demonstrations in the country that left a balance of 26 deaths nationwide. (Photo by Lucas Aguayo Araos/Anadolu Agency via Getty Images)

This undated handout image courtesy of the San Diego Zoo Wildlife Alliance shows “Pat”, a Pacific pocket mouse fondly named after actor Sir Patrick Stewart. A mouse named after “Star Trek” actor Patrick Stewart is officially the world's oldest in captivity, a US zoo has announced Pat the Pacific Pocket Mouse – the smallest species of mouse in North America – bagged the title when he hit nine years and 209 days old on February 8, 2023. (Photo by Ken Bohn/San Diego Zoo Wildlife Alliance via AFP Photo)

Members of the Pentacle Drummers perform in front of a burning wicker man during the Beltain Celtic Fire Festival at Butser Ancient Farm, in Waterlooville, Hampshire on Saturday, April 29, 2023. (Photo by Andrew Matthews/PA Images via Getty Images)