A JAPANESE zoo has culled 57 native snow monkeys by lethal injection after finding that they carried genes of an “invasive alien species,” officials said Tuesday.

    The Takagoyama Nature Zoo in the city of Futtsu in Chiba prefecture east of Tokyo, housed 164 simians which it believed were all pure Japanese macaques.

    But the operator and local officials discovered about one-third were crossbred with the rhesus macaque, which in Japan is designated an “invasive alien species.”

    A city official said Tuesday that Japanese law bans the possession and transport of invasive species, including the crossbreeds, and that culling of them is allowed under the law.

    He said the monkeys were put to death by lethal injection over about one month ending early February.

    The zoo operator held a memorial service for the monkeys at a nearby Buddhist temple to appease their souls, he added.

    Snow monkey-rhesus macaque crossbreeds were designated for culling when Japan’s environment law was revised in 2013.

    “They have to be killed to protect the indigenous environment,” an official with the Chiba prefectural government said.

    But Japan’s Environment Ministry said exceptions could be made, such as cases in which zoos apply for permission to keep them.

    “There are many zoos in the country, which rear animals that became classified as invasive species after the law was created,” a ministry official said.

    (SD-Agencies)