Only after World War II did the secret spill: Ōkunoshima, located in the Inland Sea of Japan between Hiroshima and Shikoku, was the top-secret site for manufacturing chemical warfare. When the factories were closed down, a number of exotic wild rabbits were seen freely roaming the island. They were assumed to have been the test subjects for the chemical weapons, which the military failed to eradicate when the factory was demolished.

Men give bananas to monkeys gathered on the side of the road as India remains under an unprecedented lockdown over the highly contagious coronavirus (COVID-19) on April 08, 2020 in New Delhi, India. Wild animals, including monkeys, are roaming human settlements in India as people are staying indoors due to the 21-day lockdown. (Photo by Yawar Nazir/Getty Images)

Tasmanian devils play on May 31, 2023 in Sydney, Australia. Creatures living at the zoo welcomed the arrival of winter with snow and an array of treats. Many of the zoo's species would naturally experience seasonal changes within their wild ranges. With the support of the SEA LIFE Sydney Aquarium's sub-Antarctic penguin team, snow is predicted to hit the Darling Harbour-based attraction on Wednesday morning. (Photo by Jenny Evans/Getty Images)

Giant panda Ying Ying rests on a rock in its enclosure while a visitor takes a selfie at Ocean Park in Hong Kong, China, 24 September 2020. An An turned 35 in August. Giant pandas in the wild can live up to 20 years on average, while lifespans of those under human care can reach over 30 years. (Photo by Jerome Favre/EPA/EFE)

One-day-old baby giraffe calf Gus looks at the camera at Noah's Ark farm on May 12, 2017 in Bristol, England. The baby giraffe was born yesterday at the zoo farm in North Somerset. In the wild, populations of giraffes are suffering from a continuing decline, with 97,500 estimated in Africa in 2015. Since 1985 the total giraffe population has fallen by 35%. New arrival Gus joins brothers George, 4 and Geoffrey, 2. (Photo by Matt Cardy/Getty Images)

A male puma, named Bordo arrives for an examination and tests at a veterinary in Brasilia, Brazil, 31 October 2017 (issued 01 November 2017). Bordo, a young male puma, captured when he was a cub, will become the first animal of his species to be released in a sanctuary in the Brazilian savannah in Goias State close to Brasilia. The sanctuary, a preserve for wild cats, is in the first phase and is located on private lands but state funded. (Photo by Joedson Alves/EPA/EFE)

A lone male cheetah is set upon by a pack of African wild dogs. Peter Haygarth had been following the dogs as they hunted in Zimanga Private Game Reserve in KwaZulu-Natal, South Africa. On first encountering the cheetah, the dogs were wary, but as the rest of the pack arrived, their confidence grew and they began to encircle the cat. Peter kept his focus on the cat’s face. In a few minutes the spat was over as the cheetah fled. (Behaviour: mammals category). (Photo by Peter Haygarth)