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)

An Iowa State Patrol trooper works the scene of an overturned semi truck along the westbound shoulder of Interstate 80 near Anita, Iowa, on Wednesday, December 15, 2021, after a band of intense weather crossed through the area. A powerful storm system is blowing through the Great Plains and Midwest, combining with unusually warm temperatures to close highways and prompt numerous tornado warnings. (Photo by Bryon Houlgrave/The Des Moines Register via AP Photo)

A woman walks between Christmas trees at a Christmas market opened prior to incoming Christmas and New Year festivities in St. Petersburg, Russia, Friday, December 15, 2023. (Photo by Dmitri Lovetsky/AP Photo)

An ancient oak tree sits in a Shropshire field as the first signs of Spring begin to show across the United Kingdom on February 19, 2014 in Bridgnorth, England. (Photo by Christopher Furlong/Getty Images)

A Rajasthani folk dance artist performs while standing on two glasses during the “Dhora Ri Mahak” festival in Bhopal, India, 07 January 2015. The event is being organised by the “Indira Gandhi Rashtriya Manav Sangrahalaya” anthropology museum. (Photo by Sanjeev Gupta/EPA)

The sunrise at Boscombe beach at Bournemouth in Dorset, southwest United Kingdom on February 23, 2021. (Photo by Steve Hogan/pictureexclusive.com)

Battersea Power Station. The chimney rims are thinner on top than you might expect. (Photo by Bradley L. Garrett)

The sunrises at 04.25am at St Mary's Lighthouse in Whitley Bay, on the North East coast of England on Tuesday, June 20, 2023, the day before Summer Solstice – the longest day of the year. (Photo by Owen Humphreys/PA Images via Getty Images)