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)

Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

Elvis Presley impersonator Sean Wright poses next to the Elvis Express train at Sydney's Central station before it departs for the 26th annual Elvis Festival being held in the New South Wales town of Parkes in Australia, January 11, 2018. (Photo by Daniel Munoz/Reuters)

Workers tend green onion plants among nearly 1,000 acres of terracing in fields in the Majalengka Regency of West Java in Indonesia in July 2021. (Photo by Andika Oky Arisandi/Solent News)

An aircraft drops water during a wildfire near Olympia town, western Greece, Thursday, August 5, 2021. Wildfires rekindled outside Athens and forced more evacuations around southern Greece Thursday as weather conditions worsened and firefighters in a round-the-clock battle stopped the flames just outside the birthplace of the ancient Olympics. (Photo by Giannis Spyrounis/ilialive.gr via AP Photo)

Italian Prime Minister Giorgia Meloni (L) is welcomed by the European Parliament President Roberta Metsola ahead of a meeting at the European Parliament in Brussels, Belgium, 03 November 2022. (Photo by Stephanie Lecocq/EPA/EFE/Rex Features/Shutterstock)

A Rajasthani man displays his moustache during the closing ceremony of annual Camel Fair in Pushkar, in India's desert state of Rajasthan, on November 8, 2022. (Photo by Himanshu Sharma/AFP Photo)

A boy swims in Chao Phraya River as he helps to place a Krathong, or a “floating basket”, in the water amid a yearly festival during which rafts of neatly folded banana leaves, decorated with flowers, candles and incense, are offered to thank the water goddess for good luck and for using her water to grow crops and support all life, in Bangkok, Thailand on November 8, 2022. (Photo by Chalinee Thirasupa/Reuters)