Fans cheer in the stands ahead of the CFL's 102nd Grey Cup football championship between the Calgary Stampeders and the Hamilton Tiger Cats in Vancouver, British Columbia, November 30, 2014. (Photo by Todd Korol/Reuters)

A woman poses for a photographer (not pictured) as a man sits next to her in downtown Catania, Italy April 20, 2016. (Photo by Tony Gentile/Reuters)

A masked reveller poses during the Venice Carnival in Venice, Italy February 12, 2017. (Photo by Tony Gentile/Reuters)

Ariana DeBose performs at the 76th Annual Tony Awards in New York City, U.S., June 11, 2023. (Photo by Brendan Mcdermid/Reuters)

American actress Elle Fanning arrives for the 77th Tony Awards at Lincoln Center in New York on June 16, 2024. (Photo by Eduardo Munoz/Reuters)

Spur Lacasse of Cochrane, Alberta rides the horse Rebel Warrior in the novice bareback event during the Calgary Stampede rodeo in Calgary, Alberta, in this July 12, 2014 file photo. (Photo by Todd Korol/Reuters)

Fallon Taylor of Collinsville, Texas, slips and falls with her horse in the barrel racing event during the Calgary Stampede rodeo in Calgary, Alberta, Canada July 8, 2016. (Photo by Todd Korol/Reuters)

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)