giraffe vet
People look on as a vet prepares to dismember Marius the giraffe at Copenhagen Zoo. The Danish zoo killed healthy giraffe and fed the 18-month-old animal's carcass to lionsReuters

The Copenhagen Zoo has euthanised four healthy lions a few weeks after it caused furor among animal lovers around the world by putting down and publicly dissecting a young giraffe.

The zoo said it killed a 16-year-old male lion, a lioness of around the same age and two younger females on Monday after a new male lion arrived on Sunday as part of a programme to renew the zoo's breeding stock.

"Now two young females born in 2012 have become mature and are healthy, they can take over from the old female and form a strong triangle with the new male," the zoo said, according to Aljazeera.

The zoo also stated that the lion cubs were too young to fend for themselves and would have been killed by the new male as soon as he got the opportunity.

The zoo was reportedly unable to find new homes for the animals.

In February, the zoo faced widespread criticism after it put down Marius, an 18-month-old giraffe, and dissected it in front of school children. The reason given for killing the animal was, 'to avoid in-breeding.'

The zoo staff received death threats after the healthy giraffe was killed. The zoo's head, Steffen Straede, said he did not expect the same reaction this time.

"I think people are more enlightened after Marius," he told the Ritzau news agency.

According to Reuters, the lions' body parts will be used for research.