Rare Asiatic lion cubs born at a Devon zoo in May have survived their first "critical" weeks.
A cub born last year had to be put down when it was two months old and vets discovered it had spinal defects
Asiatic lions have been hunted "to the edge of extinction" and the Gir Forest in Gujarat is now their only remaining natural habitat.
There are believed to be fewer than 300 of the creatures left in the wild and a similar number in zoos around the world, which operate a conservation breeding programme for endangered species.
The four cubs, who were born on 15 May, have not yet been sexed or named.
'Cautiously excited' "We don't get too close as we want them to be raised as naturally as possible," zoo spokesman Phil Knowling told BBC News.
"The cubs will stay with their mother for probably about 12 to 18 months - she's doing a good job and seems to be a natural."
For the eight-year-old father and mother, Mwamba and Indu, it is their first successful breeding after several failed attempts.
Neil Bemment, operations director and curator of mammals, said the survival of the cubs would be "very good news" for the endangered species.
"They have come through the critical first few weeks," he said.
"We have been letting Indu get on with being a new mum - so far she seems to be doing really well.
"We are cautiously excited - if she is successful then it will be thanks to a lot of care and attention from the keepers.
When the four cubs are deemed old enough, they will go to other zoos with an endangered species breeding programme.
Asiatic lions are smaller than African lions and have a distinctive fold of skin on the belly.