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)

American actress Paris Jackson pulls faces at photographers during the “Melbourne Cup” race day festivities in Melbourne, Australia on November 7, 2017. (Photo by Media-Mode/Splash News and Pictures)

People react as a Canadian man wearing only a pair of shorts orders a drink from a fast food outlet in Gangneung Curling Centre on day 10 of the PyeongChang 2018 Winter Olympic Games on February 19, 2018 in Gangneung, South Korea. (Photo by Carl Court/Getty Images)

An actor dressed as Tyrion Lannister, poses for photographers with fake severed head before the screening of final episode of “Game of Thrones” on 20-meter-high screen at RZD Arena in Moscow, Russia on May 20, 2019. (Photo by Maxim Shemetov/Reuters)

Visitors look at an elephant swimming in a pool at Khao Kheow Zoo in Chonburi, east of Bangkok, Thailand on February 4, 2020. (Photo by Chaiwat Subprasom/SOPA Images/LightRocket via Getty Images)

Shepherd brothers Mustafa Erbay and Baran Erbay train their camels on snowy grounds, enabling them to become champions in competitions held in the Aegean and Mediterranean regions in Baskale district of Van, Turkey on February 1, 2020. (Photo by Ozkan Bilgin/Anadolu Agency via Getty Images)

A fisherman waits to catch fish as he sits atop a stilt in the sea in Koggala, Sri Lanka on July 4, 2019. (Photo by Dinuka Liyanawatte/Reuters)

A resident (unseen) uses a belt to get vegetables in Wuhan, in China's central Hubei province on March 13, 2020. China reported just eight cases of the coronavirus on March 13, with no new domestic infections outside the epicentre of Hubei province. (Photo by AFP Photo/China Stringer Network)