Five rare white tiger cubs have died at New Delhi's zoo because of "neglect" by their mother, an official said Tuesday.
The cubs, born last week, died over the weekend after the seven-year-old tigress refused to feed or care for them, curator of Delhi's National Zoological Park told AFP.
"The mother did not even try to feed the cubs. She would not even hold the babies close to her. She totally neglected them," Riaz Ahmad Khan said.
The zoo said it was unable to save them because they were too young.
A sixth cub survived against the odds and is now battling for its life in a veterinary facility, where it is being fed fresh goat's milk, Khan added.
Early death is common among white tigers since they owe their appearance to a genetic mutation, which can result in other defects such as low immunity and malformed organs, experts say.
White tigers hail from eastern and southern Asia, but have not been seen in the wild in India since the 1950s, according to conservationists.
Khan said the zoo had been trying to breed its white tigers in a bid to boost numbers. The zoo has six white tigers, four of which are female.
"White tigers are very popular with visitors. We try to ensure the breeding takes place between partners born of different sets of parents," he said.
Some experts say inbreeding of white tigers to boost numbers can magnify their genetic problems.
Indian zoos have been the target of fierce criticism from wildlife experts in the past over concerns including poor sanitation, overcrowding and contaminated food.
A rhinoceros died at the Delhi zoo last year from suspected anthrax while a female giraffe died of severe diarrhoea in 2011 after contracting a virus.
In 2010, 32 blackbuck antelopes died after drinking sewage water that flowed into their enclosures at the same zoo.
"We try to give the animals the best care possible but sometimes there are situations which are unavoidable," Khan said.
India is home to 1,706 Royal Bengal tigers and less than 100 white tigers, which are all in captivity, according to the last census in 2011.
Rampant poaching and loss of habitat due to human encroachment are cited as the major challenges to tiger conservation efforts.
Explore further: Three Bengal tigers born at Paraguay zoo