Death of a white tiger in Nehru Zoological Park has shifted the focus yet again on ethical aspects of captive breeding of animals.
Captive breeding of white tigers — a genetic variation of the Royal Bengal Tiger species — has been debated against for long, as the white colour is acquired as a result of genetic mutation. On Thursday, an eight-year-old male white tiger named Kiran died of complications arising out of a neoplastic tumour in its lower jaw region. The tumour is suspected to be the result of an inherited health issue, as the father and grandfather of Kiran, both white tigers, died of similar causes.
While the genetic reasons are yet to be ascertained, experts do concur that captive breeding among white tigers is not advisable, as it compromises the immunity responses of the animals.
“World Association of Zoos and Aquariums as well as the Association of Zoos and Aquariums of USA too have issued guidelines against captive breeding of white tigers. When they are bred in captivity for white colour, they are obviously inbred. They will have compromised immunity. Their immune responses may not be as good as normal tigers. They do get some genetic defects,” said Karthikeyan Vasudevan from LaCONES.
In the wild, the chance for white members in tigers is as low as one in 10,000. Though white tigers are found only among the Royal Bengal species, no white tiger exists in the wild presently in India. Hence, captive breeding is the only option for zoos across the country to add the prized member to their animal inventories.
Generally, the rule in the zoo is to mate a white tiger with its ilk only, so that the cubs too are white in colour. Breeding between a normal and a white tiger may produce all normal cubs, as the recessive trait would be masked by the dominant trait, say experts. Prolonged inbreeding is certain to result in more and more genetic anomalies. Already, white tigers suffer from reduced life span compared to their normal cousins. Sources from the Nehru Zoological Park, however, provide other reasons too for the inbreeding. “We keep white tigers for educative and research purposes. We actually got another white tiger from Tirupati zoo to avoid the problems associated with inbreeding, but the tigers that died of tumours belonged to the same line. Another reason to restrict mating only among whites is to avoid passing of the recessive gene to normal tigers thereby perpetuating it further,” an expert from the zoo explained.While there are other zoos such as Nandankanan, Alipore and the National Zoological Park, which keep white tigers, the Nehru Zoological Park has the highest numbers at nine.
