There are now less than 400 Sumatran tigers in the wild
One of four rare Sumatran tiger cubs born earlier this year at a Devon zoo has been put down after it was seriously injured.
Kemala, a six-month-old female, broke both shoulders in a bad fall in her enclosure at Paignton Zoo on Thursday.
The cubs, born to mother Banda and father Tenang, are part of a Europe-wide captive breeding programme aimed at saving the endangered species.
The zoo said devastated keepers found the cub soon after the fall.
Zoo spokesman Phil Knowling said vets did all they could for the cub, but the decision was taken to put it to sleep on Saturday.
"It's a great shame and everybody's very down about it," he said.
"When you work with animals, particularly rare species, you have your ups and your downs and this is definitely a low point."
A second cub, Aryo, who is limping, is being closely monitored by the zoo's keepers.
It is thought he may have hurt himself in a "rough and tumble" with Kemala.
When the cubs were born, Paignton Zoo set up cameras in their den to enable the public to see them on the internet.
The World Wildlife Fund has estimated there are now less than 400 Sumatran tigers left in the wild. The animals have been endangered by loss of habitat and poaching.
Paignton Zoo is a member of the European endangered species programme for Sumatran tigers.
It works alongside other zoos to protect the species from extinction and the three remaining cubs will be moved when they are about 18 months old as part of the captive breeding programme.
It is not the first time the zoo has lost one of the rare tigers - a seven-month-old cub, thought to have a heart condition, died.