A market trader in Gaibandha in Bangladesh on September 25, 2019, surrounded by bottle gourd vegetables, which sell for around 3p ($ 0.04) each. (Photo by Solent News)

Brazilians celebrate at the annual New Year's Eve beach party on December 31, 2011 for the Copacabana Reveillon in Rio De Janeiro, Brazil. (Photo by Konrad Fiedler/Getty Images)

“Sperm whale opening it's huge mouth, Ogasawara Islands, Japan. Sperm whales are the biggest carnivorous animals on the planet. Each teeth in the mouth of adult specimen weights more than 1 kilogram. Interestingly enough that modern marine biologists believe that these teeth despite being fearsome play little role in capturing and eating giant squid – with their main function being mainly ritual aggression between males!”. (Photo by Alexander Safonov)

Maratus is a spider genus of the Salticidae family (jumping spiders). These spiders are commonly referred to as peacock spiders due to their colorful abdominal flaps that they display during courtship. In at least one species, Maratus vespertilio, the expansion of the flaps also occurs during ritualised contests between males. All described species, except M. furvus, are endemic to Australia. (Photo by Jurgen Otto)

Gymnast Valeria Kurochkina from Yekaterinburg performs during the Circus of Our Childhood festival at the Yekaterinburg Circus in Yekaterinburg, Russia on December 7, 2019. The festival marks the centenary of establishing state circuses in Russia. (Photo by Donat Sorokin/TASS)