An Oriental Garden Lizard sits on a tree in Gauhati, India, Tuesday, April 16, 2019. During the breeding season, the male lizard's head and throat turn a bright color. (Photo by Anupam Nath/AP Photo)

“Game of Thrones” star, actress Sophie Turner attends the “X-Men Dark Phoenix” Photocall At Cafe de l'Homme on April 26, 2019 in Paris, France. (Photo by Splash News and Pictures)

A worker throws a cloth during a drying process at Sukoharjo near Solo, Central Java province, Indonesia, April 23, 2019 in this photo taken by Antara Foto. (Photo by Mohammad Ayudha/Antara Foto via Reuters)

A family take a souvenir picture next to giant male panda Xiao Liwu, who was born at the San Diego Zoo and will be repatriated to China with his mother Bai Yun, bringing an end to a 23-year-long panda research program in San Diego, California, U.S., April 18, 2019. (Photo by Mike Blake/Reuters)

Brazilian actress Julia Stockler (L) and Brazilian actress Carol Duarte kiss while posing with Brazilian film director Karim Ainouz during a photocall for the film “A Vida Invisivel de Euridice Gusmao (The Invisible Life of Euridice Gusmao)” at the 72nd edition of the Cannes Film Festival in Cannes, southern France, on May 20, 2019. (Photo by Stephane Mahe/Reuters)

In this Friday, August 9, 2019, file photo, Pakistan Rangers soldiers face Indian Border Security Force soldiers at a daily closing ceremony on the Indian side of the Attari-Wagah border. India's recent clampdown has a long history in Kashmir and the conflict has existed since the late 1940s, when India and Pakistan won independence from the British empire and began fighting over rival claims to the Muslim-majority territory. India and Pakistan have fought two of their three subsequent wars over Kashmir, and each administers a portion of the region. India has long seen the Kashmiri struggle for self-determination as Islamabad's proxy war against New Delhi. (Photo by Prabhjot Gill/AP Photo/File)

16-year-old panda, Ye Ye, rests in an enclosure at the Wolong Nature Reserve, a conservation center that trains pandas for release into the wild. This image was published in the August 2016 National Geographic magazine as part of the “Pandas Gone Wild” story. (Photo by Ami Vitale/National Geographic Creative)

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)