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 mahout cleans the dust from his elephant in Ahmedabad, India, February 8, 2017. (Photo by Amit Dave/Reuters)

Workers sleep on a railway track under repair in New Delhi, India, June 15, 2018. (Photo by Saumya Khandelwal/Reuters)

Ukrainian law enforcement officers restrain an activist of women's rights group Femen, who holds a protest outside the presidential administration headquarters while marking the International Day for the Elimination of Violence against Women in Kyiv, Ukraine on November 25, 2020. (Photo by Valentyn Ogirenko/Reuters)

The camera rolls as actors dressed as historical Chinese soldiers act as though they have been hit by artillery, during filming of “The Last Prince” television series on location near Hengdian World Studios near Hengdian July 24, 2015. Hundreds of well-trained actors and other professionals are available at the Hengdian World Studios. The well-organised team coordinate complicated battle scenes to satisfy the huge appetite for productions about the war against Japan. (Photo by Damir Sagolj/Reuters)

In this October 29, 2013 photo, Daniel smokes marijuana inside his apartment where he uses a hydroponics system to grow his weed in Mexico City. “I'm not a narco, dude. I just like to smoke”, said Daniel, who spoke on condition that his last name not be used because, he said, his home-grow operation is "super-illegal" despite being for personal use only. (Photo by Eduardo Verdugo/AP Photo)

People wear face masks while participating in the annual Memorial Day Parade on May 25, 2020 in the Staten Island borough of New York City. Dozens of cars and nearly 100 members of the patriotic motorcycle group Rolling Thunder joined the event. This year’s parade was diminished in size and in person-to-person contact due to the coronavirus outbreak. Across the country, events honoring the nation’s veterans have been cancelled or scaled back as America continues to experience high numbers of deaths and new cases of COVID-19. (Photo by Spencer Platt/Getty Images)

In this April 12, 2015 photo, Sayed Ahmed Abdoh poles his boat to check his fish traps in the Nile River, near Abu al-Nasr village, about 770 kilometers (480 miles) south of Cairo, Egypt. Abdoh caught some 20 fish this day and gave them to his friend, Salama Osman, a migrant worker in a Cairo apartment building, to celebrate his biannual return to their village. (Photo by Hiro Komae/AP Photo)