Zoo spokesman Tobias Stenbaek Bro said Monday that he and the zoo's scientific director, Bengt Holst, received several threats over the telephone and in emails. They quoted one email as saying: "The children of the staff of Copenhagen Zoo should all be killed or should get cancer."

The giraffe, Marius, was killed on Sunday using a bolt pistol, then skinned and fed to lions in front of visitors, including children.

Marius, a healthy male, was put down Sunday using a bolt pistol, said zoo spokesman Tobias Stenbaek Bro. Visitors, including children, were invited to watch while the giraffe was then skinned and fed to the lions.

Marius' plight triggered a wave of online protests and renewed debate about the conditions of zoo animals. Before the giraffe was killed, an online petition to save it had received more than 20,000 signatures.

But the public feeding of Marius' remains to the lions was popular at Copenhagen Zoo. Stenbaek Bro said it allowed parents to decide whether their children should watch what the zoo regards as an important display of scientific knowledge about animals.

Stenbaek Bro said the zoo, which now has seven giraffes left, was recommended to put down Marius by the European Association of Zoos and Aquaria because there already were a lot of giraffes with similar genes in the organization's breeding programme.

The Amsterdam-based EAZA has 347 members, including many large zoos in European capitals, and works to conserve global biodiversity and achieve the highest standards of care and breeding for animals.