A Danish zoo that prompted international outrage by putting down a healthy giraffe and dissecting it in public has killed two lions and their two cubs to make way for a new male.

"Because of the pride of lions' natural structure and behaviour, the zoo has had to euthanise the two old lions and two young lions who were not old enough to fend for themselves," Copenhagen zoo said.

The 10-month-old lions would have been killed by the new male lion "as soon as he got the chance", it said.

The four lions were put down on Monday after the zoo failed to find a new home for them, a spokesman said. All four were from the same family.

He said there would be no public dissection of the animals since "not all our animals are dissected in front of an audience".

Within a few days the new male will be introduced to the zoo's two female lions, who have reached breeding age.

The zoo's chief executive, Steffen Straede, said: "The zoo is recognised worldwide for our work with lions, and I am proud that one of the zoo's own brood now forms the centre of a new pride of lions."

Last month the zoo's scientific director, Bengt Holst, received death threats over the decision to kill an 18-month-old giraffe, Marius, who was put down with a bolt gun before children were allowed to watch his body being chopped up, dissected and fed to lions.

The move shocked thousands of animal lovers around the world who had signed an online petition to save him. The zoo said on its website it had no choice but to prevent the animal attaining adulthood since under European Association of Zoos and Aquaria rules inbreeding between giraffes is to be avoided.

Many Danes were surprised and even angered by the international reaction to the event, with a leading expert on the ethics of the treatment of animals decrying the "Disneyfication" of zoo creatures.