Japan zoo kills 57 snow monkeys over 'alien genes'

A zoo in Japan has culled 57 of its snow monkeys by lethal injection after discovering they carried the genes of an 'invasive alien species'.

Takagoyama Nature Zoo in Chiba, northern Japan, said DNA testing showed the monkeys had been crossbred with the rhesus macaque, which is non-indigenous and banned under Japanese law.

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A local official said the animals had to be killed to protect the native environment. If they escaped, they could reproduce in the wild and threaten the native species.

According to the BBC, Junkichi Mima, a spokesman for conservation group WWF Japan told AFP news agency that invasive species, including crossbreeds, cause problems "because they get mixed in with indigenous animals and threaten the natural environment and ecosystem".

According to the Telegraph, the zoo operator held a memorial service for the monkeys at a nearby Buddhist temple.

Japanese macaques, known as snow monkeys, are a popular tourist attraction, and can often be seen bathing in hot springs in the wild.

According to Wikipedia, the Japanese macaques a terrestrial Old World monkey species that is native to Japan. They get their name snow monkey because they live in areas where snow covers the ground for months each year – no other nonhuman primate is more northern-living, nor lives in a colder climate.

Individuals have brown-grey fur, red faces, and short tails.