Exit white tigress, enter chinkaras at Delhi Zoo

Currently, the capital's zoo has three pairs of endangered chinkara (Gazella bennettii) but the animals are at risk from inbreeding, which makes it mandatory to borrow animals from other zoos to maintain the genetic diversity of offspring, says Delhi Zoo officials.

"The two pairs of Chinkara are being brought from Gwalior to reduce inbreeding and slow down the loss of vigour as the existing animals have inbreeded for two to three generations.

But the continued inbreeding results in terminal lack of vigour and probable extinction as the gene pool contracts, fertility decreases, abnormalities increase and mortality rates rise," says Anand Krishna, currently in-charge of Delhi Zoo.

Line-breeding is still a form of inbreeding i.e. breeding within a family line and includes between two cousins, aunt and nephew, niece and uncle as well as between grandparent and grandchild. However, on the other hand, too much outcrossing is also not advisable as it can cause loss of type and therefore loss of a distinct breed.

The official says currently the zoo is the home for two male and female white tigers. The Bengal tiger (Panthera tigris tigris) is a subspecies of the tiger and is found in India, Bangladesh, Nepal, Bhutan, Burma, and southern Tibet.  Tigers are among the world's most threatened species, with only an estimated 3,200 remaining in the wild, according to the World Wildlife Fund.

Being hunted for game the chinkara population is also on the decline. Although Chinkara are under Schedule I of the Wildlife Protection Act, they still fall prey to occasional incidents of poaching. In a famous case film star Salman Khan was sentenced to five years in prison for shooting chinkara and blackbuck in Rajasthan.

"Besides, we have recently added a pair each of endangered fox and jackal and a highly poisonous Russel Viper for exhibit through exchange programme. Fox and jackals have been acquired from Bilaspur Zoo while Russel's Viper, a venomous snake is from Bagalore Zoo," says Krishna.