Copenhagen Zoo has killed a healthy giraffe because of rules imposed by a European zoo association to deter in-breeding despite a wave of online protests to save it.

Zoo spokesman Tobias Stenbaek Bro says it put down the male giraffe, named Marius, on Sunday using a bolt pistol and will feed its meat to carnivores in the zoo.

Stenbaek Bro says the zoo was recommended to put down the giraffe by the European Association of Zoos and Aquaria because there were already a lot of giraffes with similar genes in the organization’s breeding program.

Mr. Stenbaek Bro said EAZA membership isn’t mandatory but most responsible zoos are members of the organization, which works to conserve global biodiversity.

An online petition to save Marius had received more than 20,000 signatures.