Stefan Dobrovolny of Austria and Inigo Munoz Elorza of Spain (R) stand in front of a quad bike during a simulated Mars mission on Tyrolean glaciers in Kaunertal, Austria, August 7, 2015. The Austrian Space Forum is sending some of its researchers to practice weight-less walking in spacesuits on a glacier which resembles the terrain on Mars. (Photo by Dominic Ebenbichler/Reuters)

Edinburgh Zoo is proud to introduce this baby three-banded armadillo Rica who was born to mum Rio and dad Rodar in Edinburgh, Scotland, UK on Sunday 24 August 2014. A tiny 81g at birth and around the same size as a golf ball, Rica is a female three banded armadillo who has grown rapidly in her first month, already quadrupling in weight. (Photo by SWNS/ABACAPress)

Goyo, an eight-month-old mini pig, plays with a dog in Mexico City, December 21, 2015. Mini pigs can grow to about 30 kg (66.1 lbs) in weight and about 35 cm (1.1 ft) in height, according to the company Mini Pigs Mexico. The company says that the mini pigs' popularity as pets is growing and around 300 are sold every year in Mexico, with prices ranging from $350 to $1,600. (Photo by Edgard Garrido/Reuters)

Pensioner Karl Szmolinsky, who raises a breed of rabbits called giant grays, shows Robert 2, an 8.5kg giant grey who is 74cm long and has ears 25.5cm long, in the backyard of his house on January 15, 2006 in Eberswalde, Germany. In November Szmolinsky sold eight giant greys to a delegation from North Korea, whom he said want to raise the breed as a source of meat for the North Korean population. Szmolinsky said his rabbits reach a maximum weight of 10.5 kg (23.1lbs.). (Photo by Sean Gallup/Getty Images)

Gorillas sit next to a ruler during a photocall for the annual weigh-in at London Zoo in London, Britain August 24, 2017. During the weigh-in, animals across the zoo have their vital statistics recorded including their height and weight and the information is then shared with zoos across the world to help zookeepers compare important information on thousands of endangered species. (Photo by Neil Hall/Reuters)

Dont get catty. These roar-some images show the moment two female tigers came to blows in a bitter dispute over territory. Rarely ever seen in the wild let alone on camera, the dramatic images show a white Siberian tiger and orange-coloured tiger slashing ferociously at each others face and eyes. The intense altercation erupted into violence when the smallest of the pair, the orange striped tiger known as Shadow, attempted to expand its hunting ground. But white tiger, TiBo, wasnt willing to give up the ground without a fight and was forced to use its size and weight to put Shadow firmly back in her place. (Photo by Alex Kirichko/Caters News/SIPA Press)

“The Sumatran Rhinoceros (Dicerorhinus sumatrensis) is a member of the family Rhinocerotidae and one of five extant rhinoceroses. It is the only extant species of the genus Dicerorhinus. It is the smallest rhinoceros, standing about 120–145 centimetres (3.9–4.76 ft) high at the shoulder, with a body length of 250 centimetres (8.2 ft) and weight of 500–800 kilograms (1,100–1,800 lb). Like the African species, it has two horns; the larger is the nasal horn, typically 15–25 centimetres (5.9–9.8 in), while the other horn is typically a stub. A coat of reddish-brown hair covers most of the Sumatran Rhino's body”. – Wikipedia

Photo: Emi, a Sumatran rhinoceros lies in the mud with her three-week-old female calf at the Cincinnati Zoo and Botanical Garden August 19, 2004 in Cincinnati, Ohio. Emi made history by becoming the first Sumatran rhino to produce two calves in captivity. (Photo by Mike Simons/Getty Images)