Uproar as giraffe put down at Denmark zoo

Despite widespread protest, Copenhagen Zoo has put down a healthy giraffe to prevent inbreeding.

A healthy young giraffe named Marius who was shot dead and autopsied in the presence of visitors to the gardens at Copenhagen zoo (AAP)

A Danish zoo has sparked outrage as it put down a young giraffe then chopped it up and fed it to lions as visitors, including young children, looked on.

The fate of 18-month-old Marius shocked animal lovers around the world, with thousands signing an online petition to save him and a billionaire offering to buy him and keep him in his Beverly Hills garden.

Copenhagen Zoo said the action was necessary to prevent inbreeding and Marius was put down with a bolt gun after being anaesthetised.

A crowd of visitors, including small children, looked on as an autopsy was carried out and the animal skinned and chopped up.

Some grimaced while others took photos.

A full-maned lion later tucked into the giraffe's remains in full view of the public.

"It was put down at 9.20. It went as planned. It's always the people's right to protest. But of course we have been surprised," zoo spokesman Tobias Stenbaek Bro told AFP.

He said some zoo staff had received death threats including scientific director Bengt Holst who "received a call in the middle of the night".

In a statement on its website, the zoo said that under European Association of Zoos and Aquaria (EAZA) rules, inbreeding between giraffes was to be avoided.

It said it had no choice other than to prevent the animal attaining adulthood, stating that castration is considered cruel with "undesirable effects" and there was no program to release giraffes into the wild.

The giraffe's impending death sparked outrage online, with more than 33,000 people signing various "Save Marius" petitions.

A Swedish zoo, which is not part of the EAZA network, tried in vain to get Marius transferred, while a Danish promoter living in Los Angeles, Claus Hjelmbak, told a Danish newspaper he had found a buyer, but that the zoo's director was not interested in a sale.

A wildlife park in Britain said it had urgently contacted the zoo on Saturday to adopt Marius but had received no response.