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 squirrel fights for its life in the bill of a great blue heron at the Mission Trails Regional Park in California in the second decade of April 2025. (Phoot by Decker Nomura/Solent News & Photo Agency)

Ring-tailed lemurs sit on the hood of a truck while snacking inside the Buin Zoo in Santiago, Chile, Tuesday, June 15, 2021. The largest private zoo in Chile, experiencing a serious economic situation due to the closure of its doors as a result of the prolonged quarantine measures, has started a campaign coined, “Sponsor an Animal”, to raise money to maintain the animals. (Photo by Esteban Felix/AP Photo)

A green iguana, or American iguana sits on an Aldabra giant tortoise, the largest tortoise of the world, in their enclosure at the zoo park of Lille, northern France, on February 11, 2019. (Photo by Philippe Huguen/AFP Photo)

A grey seal basks under a rainbow on a beach on the Lincolnshire coast, England on November 21, 2017. (Photo by Sean Weekly/Caters News Agency)

A flying lemur glides through the air in West Java, Indonesia in the first decade of October 2023. The photographer said the animal veered away from him at the last minute. (Photo by Dzul Dzulfikri/Animal News Agency)

These Eurasian Otters seem ready for any danger as they all stand up on thier hind legs alert to any threats near to the English river bank. Amateur photographer and retired MOD worker Tony Moir, 57, spotted the otters whilst looking for kingfishers to photograph near the river Trent in East Yorkshire, UK. He was able to take just a couple of pictures before the excited animals spotted the photographer and ran away. (Photo by Tony Moir/Solent News)

A gaggle of goslings huddle together under the protective wing of a parent along the bank of the Deschutes River as a heavy downpour passes through Bend, Oregon, late Wednesday, April, 20, 2106 afternoon. (Photo by Ryan Brennecke/The Bulletin via AP Photo)