A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

An Indian rag picker collects plastic bags at an industrial area on the outskirts of Jammu, India, Tuesday, June 5, 2018. The U.N. says government bans on plastic can be effective in cutting back on waste but poor planning and follow-through have left many such bans ineffective. (Photo by Channi Anand/AP Photo)

Two Girls who managed to evade the police walk away as police on foot and horseback push back to te curd at Park Row, In New York on April 26, 1960, A milling throng of more than 1,000 High students who storned city hall in a Demonstration supporting teachers wage demands. (Photo by AP Photo)

A woman poses after she got an image of a lion tattooed on her back as part of awareness campaign to save Asiatic lions and in preparations for the upcoming Navratri festival in Ahmedabad, India, October 5, 2018. (Photo by Amit Dave/Reuters)

Playboy founder Hugh Hefner (not pictured) arrives at Stansted Airport on June 2, 2011 in Stansted, England. The photograph is a recreation of a picture originally taken in the 1960's, with ten of the new London Bunnies. Mr Hefner is back in the UK to mark the launch of the new Playboy Club in Mayfair, which opens on June 4. The clubs opening will welcome back the iconic Playboy Bunny to Londonafter a 30 year absence. Famous Bunnies have included Debbie Harry and Lauren Hutton. (Photo by Dan Kitwood/Getty Images)

A mother bear takes a dip in the water to cool off in the warm summer sun but refuses to leave her three youngsters behind – so they climb aboard her back. (Photo by Jon Langeland/Solent News & Photo Agency)

Dhruva Aliman does a back somersault as he dismounts from a slackline on the beach at Santa Monica, California on October 19, 2014. Slackline is a balance sport where a line of webbing is adjusted at different levels of tension between two anchor points and participants (called slackers) perform tricks and stunts including somersaults. (Photo by Mark Ralston/AFP Photo)

Kristen Wiig (2nd L) and Maddie Ziegler (2nd R) dance to Sia's “Chandelier” as the artist (R) stands with her back to the audience while performing at the 57th annual Grammy Awards in Los Angeles, California, February 8, 2015. (Photo by Lucy Nicholson/Reuters)