Somalis remove the body of a man killed in a blast in the capital Mogadishu, Somalia Saturday, October 14, 2017. A huge explosion from a truck bomb has killed at least 20 people in Somalia's capital, police said Saturday, as shaken residents called it the most powerful blast they'd heard in years. (Photo by Farah Abdi Warsameh/AP Photo)

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)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

A woman walks protecting herself from rain after Hurricane Matthew in Les Anglais, Haiti, October 13, 2016. (Photo by Andres Martinez Casares/Reuters)

A Hindu devotee offers prayers at the Sangam, the confluence of three rivers – the Ganges, the Yamuna and the mythical Saraswati, to take a ritualistic bath during Makar Sankranti festival that falls during the annual traditional fair of Magh Mela festival, one of the most sacred pilgrimages in Hinduism, in Prayagraj, India. Friday, January 14, 2022. (Photo by Rajesh Kumar Singh/AP Photo)

Medical students play with coloured powder as they participate in Holi celebrations, the Hindu spring festival of colours, inside Moti Lal Nehru Medical College campus in Allahabad on March 16, 2022. (Photo by Sanjay Kanojia/AFP Photo)

A protester lies on the ground after being pushed during a protest over coronavirus disease (COVID-19) restrictions in mainland China, during a commemoration of the victims of a fire in Urumqi, in Hong Kong, China on November 28, 2022. (Photo by Tyrone Siu/Reuters)

Sümi women gesture as they line up to perform a traditional Sümi rice pounding folk song called “Thishole” during Western Sumi Torimi Hoho Silver Jubilee at Thilixü Village in Chumoukedima district, India north eastern state of Nagaland on June 7, 2023. Altogether 1400 Sülimis perform their traditional rice pounding folk song to mark their 25th Anniversary. (Photo by Caisii Mao/Rex Features/Shutterstock)