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)

A recently hatched baby Egret bird seen in a nest at the Gatorland Bird Rookery in Kissimmee, Florida on March 17, 2022. Gatorland is known as The Alligator Capital of the World and has a 10 acre natural bird rookery. (Photo by Ronen Tivony/SOPA Images/Rex Features/Shutterstock)

Vegas Golden Knights center Mattias Janmark (26) punches Nashville Predators center Nick Cousins (21) in a fight during the third period at T-Mobile Arena in Las Vegas, Nevada on March 24, 2022. (Photo by Stephen R. Sylvanie/USA TODAY Sports)

A monkey tries to quenche its thirst from a water tap on a hot summer day in Prayagraj on May 20, 2023. (Photo by Sanjay Kanojia/AFP Photo)

A dolphin swims alongside ships and fishing boats at the Bosphorus in Arnavutkoy district of Istanbul, Turkiye on May 21, 2023. (Photo by Isa Terli/Anadolu Agency via Getty Images)

A family pose for a picture as thousands of redheads fill a Dutch city Breda to celebrate International Redhead Day event in Breda, The Netherlands on Sunday, 4 September 2016. Every year natural redheads from more than 80 countries come together at “Roodharigendag” annual weekend long festival to celebrate their ginger genes. The event also holds the world record for the largest number of natural redheads being in one place. (Photo by Akmen/London News Pictures)