“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

A firefighter carries a woman from her car after it was caught in street flooding as a powerful storm moves across Southern California on February 17, 2017 in Sun Valley, California. After years of severe drought, heavy winter rains have come to the state, and with them, the issuance of flash flood watches in Santa Barbara, Ventura and Los Angeles counties, and the evacuation of hundreds of residents from Duarte, California for fear of flash flooding from areas denuded by a wildfire last year. (Photo by David McNew/Getty Images)

The Grevy’s Illusion by Yaron Schmid, USA: a Grevy’s zebra staring at the camera in Lewa, Kenya. Third place – wildlife. (Photo by Yaron Schmid/The Nature Conservancy Global Photo Contest 2019)

Novice DSLR (Digital single-lens reflex camera), 2nd Place. “Smile of a Friend”, American Crocodile (Crocodylus acutus) in Jucaro, Cuba. (Photo by Antonio Pastrana/The Ocean Art 2018 Underwater Photography Competition)

A squid swims underwater off the shore of the coastal city of Qalamun, north of the Lebanese capital Beirut, on September 24, 2019. (Photo by Ibrahim Chalhoub/AFP Photo)

Sinterklaas (R) a legendary figure based on Saint Nicholas, Christian patron saint of children, and page Sooty Piet have a video call with children in Dodewaard, the Netherlands, 01 December 2021. The Christian feast of Saint Nicholas is celebrated annually with the giving of gifts on the eve of 05 December in The Netherlands. (Photo by Remko de Waal/EPA/EFE/Rex Features/Shutterstock)

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 woman falls to the beach after she was attacked by three white women segregationists, when she attempted a wade-in with several African American and white desegregationist demonstrators, June 23, 1964, St. Augustine Beach, Fla. The people in the photo are unidentified. (Photo by AP Photo/JK)