A Humboldt penguin stands on weighing scales whilst being photographed by members of the press during a photocall at the annual weigh-in at London Zoo in London, Britain, 24 August 2016. Every animal that is in the zoo is weighed and measured and the statistics recorded so the data can be shared with zoos across the world. (Photo by Hannah McKay/EPA)

Two chimpanzees share a piece of watermelon at Taronga Zoo on December 23, 2010 in Sydney, Australia. (Photo by Rick Stevens/Taronga Zoo via Getty Images)

“Boom, a three-year-old Staffordshire Bull Terrier, who loves birds and rabbits. He has already acquired a legion of fans on his Facebook page, and who can blame them? He might actually be the cutest pup we've ever laid eyes on (and his little buddies seem to agree). Check out these pics and see if you don't fall in love!” (Photo by Boom)

Visitors to the Nightmare Fears Factory in Niagara Falls, Canada, are obliged to navigate their way round the supposedly haunted building in total darkness while live actors jump out of them. The Nightmare Fears Factory team have been using hidden cameras to take pictures of their guests' terrified reactions, which they've then posted on the company's Facebook page. And it turns out they're all pretty funny. (Photo by Nightmare Fears Factory)

German photographer Tobias Lang had a brilliant idea, he started photographing his friends and their pets and suddenly folks from all over the world where asking him to capture them too. Check out his Facebook page to see. Tobias is in the process of putting together a coffee table book of his impressive collection. Photo: Pet owner Isabel with her blind housecat, “Captain Jack”. (Photo by Tobias Lang)

As national soccer teams and the photographers who have been covering them start to trickle home from the Brazil World Cup, it’s time to revisit the “On the Sidelines” project. This Reuters Pictures project was billed as a chance for photographers to share “their own quirky and creative view of the World Cup”. Photo: People watch from outside as a dancer performs inside a bar in Porto Alegre June 21, 2014. In a project called “On The Sidelines” Reuters photographers share pictures showing their own quirky and creative view of the 2014 World Cup in Brazil. (Photo by Marko Djurica/Reuters)

Elaine Vandiver shares a moment with a two-year old alpaca as they touch noses as she washes him at her farm at 1560 Stateline Road Monday, May 11, 2015, in Walla Walla, Wash. (Photo by Michael Lopez/Walla Walla Union-Bulletin via AP Photo)