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)

October winner. “A burst of the aurora borealis over Kirkjufell, taken in September 2016. This shot has been a holy grail for me and was finally captured after many trips”. MICK RYAN, JUDGE: Iceland is a hotspot for aurora photography and this composition of the symmetric, free-standing Kirkjufell and the trident waterfall is much-sought after. If you can time your visit when the aurora “kp” index is high and know the settings for nighttime aurora images, you may end up with a beautiful photograph like this. (Photo by DВ/The Guardian)

An activist is juggling next to police officers at the Dannenrod forest, during a protest of environmentalists against the extension of the A49 motorway, near Dannenrod, Germany, November 27, 2020. (Photo by Kai Pfaffenbach/Reuters)

Trialist Pavel Prikhodko attempts to pull an An-2 plane as a cat walks nearby during a charity event near the village of Tatarka in Stavropol Region, Russia on December 27, 2020. (Photo by Eduard Korniyenko/Reuters)

Students on their way home from school play in a river which has risen due to recent seasonal rains, in a remote village in Panca, Aceh province on January 22, 2021. (Photo by Chaideer Mahyuddin/AFP Photo)

Garbage men race on their tricycles along the track during the garbage men bicycle race at Ban Jelacic square in Zagreb, Croatia, 19 August 2020. Zagreb's authorities organised a street festival named “Cest is the best” despite the coronavirus pandemic in Croatia with some 219 infected people. (Photo by Antonio Bat/EPA/EFE)

A team of female swimmers wearing facekini pose on beach by the sea on August 18, 2020 in Qingdao, Shandong Province of China. (Photo by Qian Han/VCG via Getty Images)

People dance during a heavy metal concert at Omni Space in Beijing, China, August 14, 2020. China boasts a small but buoyant heavy metal scene, where bands mix genre standards with Chinese elements. Black metal is a sub-genre that creates a dark, moody atmosphere layering heavily distorted guitars and high-pitched vocals. (Photo by Thomas Peter/Reuters)