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 dachshunds is dressed in an outfit as it is shown off during the eighth annual Dachshunds Parade in Saint Petersburg, Russia on May 25, 2019. (Photo by Olga Maltseva/AFP Photo)

The sun bear (Ursus malayanus), also known as the honey bear, is a bear found primarily in the tropical rainforest (the dense lowland forests) in Southeast Asia; North-East India, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Southern China, Peninsular Malaysia, and the islands of Sumatra and Borneo.

A person rides a swing hanging from a crane with hot air balloons fly in the background in Nevsehir, Turkey on October 14, 2021. Tourists and those who want to take photos set up swings on the cranes they rent and then have their photos taken in the setting created by hot air balloons in the backgrounds. (Photo by Behcet Alkan/Anadolu Agency via Getty Images)

Flames burn in a field in Capaci, near Palermo, in Sicily, southern Italy, Wednesday, July 26, 2023. On the island of Sicily, two people were found dead Tuesday in a home burned by a wildfire that temporarily shut down Palermo's international airport, according to Italian news reports. Regional officials said 55 fires were active on Sicily, amid temperatures in the 40s Celsius. (Photo by Alberto Lo Bianco/LaPresse via AP Photo)

A man looks inside an overturned truck after an accident along the road between Nouahibou and Nouakchott, Mauritania December 3, 2009. (Photo by Rafael Marchante/Reuters)

Runner-up; Hon Yen marine ecosystem. Phu Yen, Vietnam. Every year between May and August, the coral of this rich and diverse ecosystem becomes exposed at low tide. (Photo by Truong Hoai Vu/Royal Society of Biology Photography Competition)

Miniscule larvae carve winding tunnels as they eat through small leaves in a small forest near the town of Velbert in western Germany in July 2022. The hungry green sawfly larvae measure just three millimetres in length and are difficult to spot on the leaves of the beech tree unless up close. (Photo by Christian Brockes/Solent News)