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)

Crocodile meat parts stands on display on Huangsha Seafood Market in Guangzhou, Guandong Province, China, 20 January 2018. Tsukiji Market of China or Huangsha Seafood Market is biggest one in Southern China and one of the biggest in China, as there are literally hundreds of different varieties of fish and seafood scattered throughout the market. (Photo by Aleksandar Plavevski/EPA/EFE)

Children enjoy a sledge ride past ice swimming fans at the Zalew Zegrzynski lake in Nieporet, Poland, Sunday, February 25, 2018. A cold wave hit Poland with the temperature minus 8 degree Celsius (17.6 Fahrenheit) during the day and dropping to minus 16 degree Celsius (3.2 Fahrenheit) in the night in central Poland. (Photo by Alik Keplicz/AP Photo)

A boy plays with pelicans in Yoff, commune of Dakar, Senegal March 14, 2018. (Photo by Zohra Bensemra/Reuters)

An effigy representing Judas Iscariot burns as some people wearing masks watch during Holy Week in the Catia neighborhood of Caracas, Venezuela, Sunday, April 4, 2021. The Burning of Judas is an Easter-time ritual in many communities, where an effigy of Judas Iscariot is hanged on Good Friday, then burned on Easter Sunday. (Photo by Matias Delacroix/AP Photo)

An empty Turcot Interchange is shown in Montreal, Saturday, January 9, 2021, as the Quebec government imposed a curfew to help stop the spread of COVID-19 starting at 8 p.m until 5 a.m and lasting until Feb. 8. (Photo by Graham Hughes/The Canadian Press via AP Photo)

Addis Ababa police officers take part in a parade to display their new uniforms, and their readiness for the upcoming Ethiopian parliamentary and regional elections, in Addis Ababa, Ethiopia, June 19, 2021. (Photo by Baz Ratner/Reuters)

People take home sacrificial animals after purchasing it at a cattle market ahead of the Muslim festival of Eid al-Adha in Karachi on July 19, 2021. (Photo by Asif Hassan/AFP Photo)