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)

People visit a frozen waterfall illuminated by colorful lights at Dadunxia sceneic area on December 25, 2022 in Linxia Hui Autonomous Prefecture, Gansu Province of China. (Photo by Shi Youdong/VCG via Getty Images)

A palm squirrel and ring-rosed parakeet compete for space on a stump in a residential area of Chandigarh, India in the last decade of August 2024. (Photo by Anuj Jain/Solent News)

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)

Japanese macaques, also known as snow monkeys, play as they soak in a hot spring in Jigokudani valley in Nagano Prefecture, northwest of Tokyo Saturday, March 6, 2021. (Photo by Kiichiro Sato/AP Photo)

A Puffin jumps into its burrow with a mouthful of sea eels to feed its chick on Skomer Island, Pembrokeshire in Wales, Britain June 21, 2016. (Photo by Rebecca Naden/Reuters)

Seehund “Bruno” looks out of his transport box before making his way to the water on the beach of the island of Juist, Germany on August 14, 2013. Four young seals were released after six weeks of recovery at a rescue station in Norden-Norddeich. (Photo by Carmen Jaspersen/AFP Photo/DPA)