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)

Jack Frost, an ultra rare albino Hedgehog, that has been rescued by Prickly Pigs Hedgehog Rescue in Otley, West Yorkshire on August 23, 2020. (Photo by Danny Lawson/PA Images via Getty Images)

April Haze, a San Jose-based stripper, teaches a pole dance class to her students at Revel Room Studios in Milpitas, California, April 15, 2021. As some of the United States' estimated 3,821 strip clubs start to open up again, women who work as strippers are confronting a transformed industry. Revenue in the industry is estimated to have decreased 17.4% in 2020 and is forecast to fall another 1.5% this year, according to research by IBISWorld. (Photo by Brittany Hosea-Small/Reuters)

A musician from the Rajan Band, Kotla Mubarakpur holds on to a decorated horse as he and others wait prior to performing at a wedding on November 22, 2011 in New Delhi, India. (Photo by Daniel Berehulak/Getty Images)

Piper Hoppe, 10, from Minnetonka, Minnesota, holds a sign at the doorway of River Bluff Dental clinic in protest against the killing of a famous lion in Zimbabwe, in Bloomington, Minnesota July 29, 2015. A Zimbabwean court on Wednesday charged a professional local hunter Theo Bronkhorst with failing to prevent an American from unlawfully killing “Cecil”, the southern African country's best-known lion. The American, Walter James Palmer, a Minnesota dentist who paid $50,000 to kill the lion, has left Zimbabwe. He says he did kill the animal but believed the hunt was legal and that the necessary permits had been issued. (Photo by Eric Miller/Reuters)

Smithfield meat porters march on the Home Office, bearing a petition which calls for an end to all immigration into Britain, 25th August 1972. (Photo by Keystone/Hulton Archive/Getty Images)

Members of the Women's Organization to War on Styles (WOW) picket a dress shop in Berkeley, Calif., August 23, 1947, in protest to longer skirts and padded hips. They are the wives of GI students at the University of California. Left to right: Jackie Houser; Wanda Ames; Dorothy Inman; Terry Ligon; Ruth Van Arkel; Carrol Reynolds, and Barbara Carmichael. (Photo by AP Photo)

A Romanian honor guard soldier stands still as three military aircraft carriers are crossing the sky during a ceremony held at the Unknown Soldier Memorial, in Carol I Park, on the occasion of the Heroes' Day commemoration, in Bucharest, Romania, 10 June 2021. (Photo by Robert Ghement/EPA/EFE)