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.

Stenbaek Bro said EAZA membership isn't mandatory, but most responsible zoos are members of the organization. He said his zoo had turned down offers from other zoos to take Marius and an offer from a private individual who wanted to buy the giraffe for 500,000 euros ($680,000).

Stenbaek Bro said a significant part of EAZA membership is that the zoos don't own the animals themselves, but govern them, and therefore can't sell them to anyone outside the organization that doesn't follow the same set of rules.

He also said is important for the breeding programs to work.

The zoo's scientific director, Bengt Holst, said the giraffe breeding program is similar to those used in deer parks, where red deer and fallow deer are culled to keep populations healthy.

"The most important factor must be that the animals are healthy physically and behaviorally and that they have a good life while they are living whether this life is long or short. This is something that Copenhagen Zoo believes strongly in,'' he said in a statement.

Holst said the zoo doesn't give the giraffes contraceptives because they have "a number of unwanted side effects on the internal organs'' and the zoo believes parental care is an important part of the animal's natural behavior.

The organization Animal Rights Sweden said the case simply highlights what they believe zoos do to animals regularly.

"It is no secret that animals are killed when there is no longer space, or if the animals don't have genes that are interesting enough,'' the organization said in a statement. "The only way to stop this is to not visit zoos.''

It pointed out some zoos work to preserve species of animals, but never individual ones.

"When the cute animal babies that attract visitors grow up they are not as interesting anymore,'' it said.