Wildlife campaigners have slammed staff at a Japanese zoo for deciding “which animals live and die” after 57 snow monkeys were culled by lethal injection.
The monkeys were killed after it was found they carried genes of “invasive alien species”.
DNA testing showed that the monkeys at the Takagoyama Nature Zoo in Chiba had been crossbred with the rhesus macaque, which is not indigenous and is banned under Japanese law.
The zoo housed 164 primates which they believed were all pure Japanese macaques, AFP reports.
But it was later discovered that about one-third had been crossbred and they were culled. It is not clear when the crossbreeding occurred, or if the zoo is at fault.
Chris Draper, Born Free’s associate director, told the Huffington Post UK: “This has all the echoes of Marius the giraffe, who was killed at Copenhagen Zoo.
“It comes down to a sort of human assessment of genetic purity that determines which animals live or die.
“I think it’s tragic that these animals were culled.”
Draper said the Japanese zoo could have allowed the population to die out and control the animals’ reproduction, rather than killing the snow monkeys.
“Zoos need to assume responsibility and lifetime care for the animals they keep and breed - by that I mean a natural lifespan,” Draper said.
The zoo operator reportedly held a memorial service for the monkeys’ souls at a nearby Buddhist temple.
A local official said the animals “have to be killed to protect the indigenous environment”.
An official from the country’s environment ministry said that the culling was unavoidable because there were fears they might escape and reproduce in the wild.
A World Animal Protection spokesperson said: “Wild animal populations often need to be managed but culling animals should be a last resort, when all other options have been exhausted.
“We believe that this tragedy could have been avoided if the management was genuinely committed to the welfare of these macaques, and looking to explore humane alternatives.”
Junkichi Mima, spokesman for conservation group WWF Japan, said invasive species cause problems “because they get mixed in with indigenous animals and threaten the natural environment and ecosystem”.
In 2014, Marius the giraffe was culled to prevent inbreeding and to keep the giraffe population down.
Despite the move sparking international outrage at the time, the zoo’s scientific director, Ekstra Bladet, stood by the decision, saying: “You have to accept that there is a surplus of animals that cannot be included in the genetic chain without causing inbreeding problems. international outrage.”