A protester holds up a symbolic chain as the trial of ousted Egyptian president Hosni Mubarak continues on February 16, 2012 in Cairo, Egypt. (Photo by Carsten Koall/Getty Images)

A photographer could bear-ly believe his eyes when a bear started waving at him. The friendly animal wandered to the front of his enclosure before sitting back in full view of zoo guests. He then lifts his powerful paw and excitedly waves in an almost human-like way at his new audience. The hilarious encounter was captured by keen photographer Andrey Slepnev, 31, while on a trip to Madrid Zoo, Spain on March 24, 2016. (Photo by Andrey Slepnev/Caters News)

Pedestrians and vehicles make their way past the Potala Palace early on a rainy morning in Lhasa, capital of the Tibet Autonomous Region in China, Saturday, September 19, 2015. Chinese officials have taken foreign journalists on a visit to the region, normally off-limits to them, weeks after Communist Party officials commemorated the 50th anniversary of the establishment of the Tibet Autonomous Region. (Photo by Aritz Parra/AP Photo)

Young female Ibex on the fork of Disteis (2,200 m), near the top of the Jof di Montasio (Friuli, Italy). (Photo by Stefano Zocca)

Exhausted grave diggers rest in between funerals at a cemetery designated for Covid-19 victims in Bandung on June 15, 2021, as infection numbers soar in Indonesia. (Photo by Timur Matahari/AFP Photo)

A Salvadoran clown is seen wearing colorful clothes and face make-up during the parade within the framework of the National Salvadoran Clown Day that is celebrated on the first Wednesday of every December by legislative decree in San Salvador, El Salvador on December 07, 2022. After the pandemic crisis, dozens of Salvadoran clowns took to the streets to celebrate their day, and invite families to respect the work of bringing smiles to children and adults in El Salvador. (Photo by Alex Pena/Anadolu Agency via Getty Images)

A camel is seen in front of the pyramids, which is one of the seven wonders of the world that was visited by 14.9 million tourists last year in Giza, Egypt on February 21, 2024. The pyramids were named after the tombs of fathers, sons and grandsons, including the largest pyramid Cheops (King Khufu), the middle pyramid Khafre (King Khafre) and the small pyramid Menkaure (King Menkaure). (Photo by Utku Ucrak/Anadolu via Getty Images)

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)