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)

Shooting star by Tony Wu, US/Japan. Winner, underwater. The electrifying reproductive dance of a giant sea star. As the surrounding water filled with sperm and eggs from spawning sea stars, Wu faced several challenges. Stuck in a small, enclosed bay with only a macro lens for photographing small subjects, he backed up to squeeze the undulating sea star into his field of view. The dancing posture of spawning sea stars rising and swaying may help release eggs and sperm, or may help sweep the eggs and sperm into the currents where they fertilise together in the water. Kinko Bay, Japan. (Photo by Tony Wu/Wildlife Photographer of the Year)

Model Georgia Salpa attends the UK Premiere of “A Good Day To Die Hard” at Empire Leicester Square on February 7, 2013 in London, England. (Photo by UK Press)

(2nd from R) Miss Georgia Betty Cantrell reacts to advancing, en route to victory, at the Miss America Pageant at Boardwalk Hall, in Atlantic City, New Jersey, September 13, 2015. (Photo by Mark Makela/Reuters)

A member of the USA Knights team is seen wearing a face-like helmet shield during the International Medieval Combat championships at the castle of Belmonte, May 4, 2014, in Belmonte, Spain. The steel armor the knights wear can cost up to $10,000 and weigh 80 pounds. (Photo by Juan Naharro Gimenez/Getty Images)

Stunning images show the rolling splendor of the "iceberg capital of the world" under auroras. The photographer even includes himself in many of the shots – a signature of his that offers a fresh take on the conventional selfie, as well as providing a sense of scale to his works. Ziskas shot the photographs over a 10-day visit to western Greenland in September. Here: the photographer even includes himself in many of the shots – a signature of his that offers a fresh take on the conventional selfie, as well as providing a sense of scale to his works. (Photo by Paul Zizkas/Caters News)

People sit next to a pool where the Tower of Madrid skyscraper is reflected at sunset in Madrid, Thursday, November 26, 2015. The tower was the tallest in Spain since it was finished in 1957 until 1982. (Photo by Francisco Seco/AP Photo)

Ben Green, of St. Augustine, flies into the pool on his inflatable alligator to find the hidden lizard at the bottom of the pool in the “Evading Arrest Obstacle Course” during the inaugural Florida Man Games, Saturday, February 24, 2024, at Francis Field in St. Augustine, Fla. (Photo by Corey Perrine/The Florida Times-Union via AP Photo)