Sergeant Andrew Garrett watches K-Dog, a bottlenose dolphin attached to Commander Task Unit 55.4.3, leap out of the water while training near the USS Gunston Hall March 18, 2003 in the Persian Gulf. (Photo by U.S. Navy/Getty Images)

US Navy personnel walk on the flight deck aboard the USS Nimitz (CVN-68) aircraft carrier during its port visit to Busan on March 28, 2023. (Photo by Anthony Wallace/AFP Photo)

A decorated elephant march at the Navam Perahera, a Buddhist pageant of elephants, dancers and drummers, in Colombo February 3, 2015. Over 50 elephants participated in the street parade for Gangaramaya temple's annual Perahera festival, along with a nightly procession of traditional dancers, fire twirlers and traditional musicians. (Photo by Dinuka Liyanawatte/Reuters)

A woman poses for photographs after Gucci Cruise 2024 collection fashion show at the Gyeongbok Palace in Seoul, South Korea on May 16, 2023. (Photo by Kim Soo-Hyeon/Reuters)

Scuba divers during an ice diving class at the Sea Frogs scuba diving center in the Russian Far Eastern city of Vladivostok on January 30, 2022. The air temperature is –11°C (12.2°F), the water temperature is –2°C (28.4°F). Scuba divers undergo theoretical and practical training in ice diving and perform dives in the open water during the day and the night time as part of the Ice Diver NDL special program. (Photo by Yuri Smityuk/TASS)

A dog wearing a hat, a pair of sunglass and a lei standing in a fountain of water on August 5, 2022 in Hong Kong, China. The Hong Kong SongKran Festival will be held in a shopping centre from August 5 to 9. (Photo by Vernon Yuen/Rex Features/Shutterstock)

A woman pushes a child aboard a plastic basin as they wade through floodwaters brought about by Super Typhoon Noru on September 26, 2022 in San Miguel, Bulacan province, Philippines. Super Typhoon Noru made landfall in the Philippines overnight, causing widespread flooding and leaving at least five dead. High winds and heavy rains have flattened villages and have increased the threat of landslides. (Photo by Ezra Acayan/Getty Images)

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)