Macro or Micro? Scientists’ pictures baffle our sense of scale. It began when Stephen Young, a geography professor at Salem State University in Massachusetts, tricked his biologist colleague Paul Kelly into thinking a satellite image was one of his electron microscope scans. Can you guess whether they are close-up or very far away? (Photo by Paul Kelly)

“They're some of the most intriguing and complex creatures on the planet but they really do have nothing to hide – because theyre totally see-through. Transparent animals – creatures with clear glass-like skin – can be found all over the world but their very existence is still shrouded in mystery. The fascinating organisms verge on the invisible and their translucent skin often helps them elude predators”. – Caters News. Photo: Thornback Skate. (Photo by Ken Lucas/Caters News)

A dramatic rise in owning exotic pets in China is fuelling global demand for threatened species. The growing trade in alligators, snakes, monkeys, crocodiles and spiders is directly linked to species loss in some of the world’s most threatened ecosystems. Here: A fennec fox (Vulpes zerda) is groomed in a pet store in central Beijing. Native to the Sahara in North Africa, the species became a popular pet after being depicted as a character in Disney’s 2016 animated movie Zootopia. Individuals can cost between $2,000–$3,000. (Photo by Sean Gallagher/The Guardian)

The little new born wombat baby APARI sitting in its mothers pouch at the zoo in Duisburg, Germany, Thursday, March 29, 2018. Wombat mother TINSEL once was found in the pouch of its dead mother on a street in Australia and was raised by zookeepers before she came to Germany. The zoo tried for 40 years in vain to breed a wombat, until APARI was born as the first one last week. (Photo by Martin Meissner/AP Photo)

A food market shows off rows upon rows of dead animals, some of which have been beaten to death. Dogs and chickens can be seen lined up with their mouths hanging wide open. Shoppers even pick up some of the dogs and bats as they look for the best on the market. Retired biologist and amateur photographer Alf Jacob Nilsen took the shocking pictures of the market during a visit to Tomohon Village in Northern Sulawei, Indonesia. Pictured: Flying foxes (bats) for sale at the market. (Photo by Alf Jacob Nilsen/Solent News)

Two Herens cows lock horns during the qualification round of the annual “Battle of the Queens” cow fight finals in Aproz, in the western Alpine canton of Valais May 5, 2013. Each year when taken to the alpine pastures, the cows test their strength and fight for the herd's leadership. The competition continues until a new queen has forced all the other cows to retreat. (Photo by Valentin Flauraud/Reuters)

Ace Wu searches the deep to photograph stunning underwater creatures. Against their predominantly black backdrops, Wu’s breathtaking subjects glow with sublime vibrancy. In one, a fearsome fish glares at the camera with rows of sharp teeth showing, while in another, a translucent octopus looks like an extraterrestrial. Here: Wunderpus larva. (Photo by Ace Wu/Caters News Agency)

A comedic photo of a cheetah appearing to find something hilarious by Dutton Robert for the Comedy Wildlife Photo Awards 2016, South Africa, April, 2012. (Photo by Dutton Robert/Barcroft Images/Comedy Wildlife Photo Awards)