This photo taken on August 7, 2016 shows mahjong enthusiasts playing mahjong under water in a swimming pool at a diving club in the Chinese city of Chongqing. Only participants with proper diving certification were allowed to take part in the underwater competition. (Photo by AFP Photo/Stringer)

World medieval jousting champion Rod Walker poses before next month’s St Ives Medieval Faire, the only solid wood lance joust tournament in the southern hemisphere in Sydney, Australia on August 26, 2016. (Photo by Dan Himbrechts/AAP)

A man rides a horse through a bonfire on January 16, 2009 in the small village of San Bartolome de Pinares, Spain. In honor of San Anton, the patron saint of animals, horses are riden trough the bonfires on the night before the official day of honoring animals in Spain. (Photo by Denis Doyle/Getty Images)

Florence the baby zebra foal, runs in its enclosure at Edinburgh zoo September 4, 2008 in Edinburgh, Scotland. This arrival at the zoo is particularly important as the Grevy's zebra is listed as endangered, with only an estimated 1,500 to 2,000 remaining in the wild. (Photo by Jeff J Mitchell/Getty Images)

The quokka the only member of the genus Setonix, is a small macropod about the size of a domestic cat. Like other marsupials in the macropod family (such as the kangaroos and wallabies), the quokka is herbivorous and mainly nocturnal.