A rare three-month-old white tiger cub died at a zoo in India's capital days after it showed signs of limping.

The cub was born in August this year to a white tiger couple, seven-year-old tigress Sita, and tiger Vijay. The cub and his two other siblings were being looked after by the zoo staff, who are now mourning the loss.

Zoo director Akanksha Mahajan said that the cub collapsed on Sunday morning after showing signs of limping in the left leg, reports The Indian Express. The cub was given supplements for his condition, but they could not help the baby tiger.

"...the hind portion of the cub was not functioning last week. We began giving medication and laser therapy...but then it collapsed Sunday morning," Mahajan said.

Meanwhile, another cub has also started showing signs of limping. Its blood samples have been sent for examination to the Indian Veterinary Research Institute, Bareilly.

"The report will be able to tell us if it's a pathological problem or a genetic one. There are two probabilities — it could be a viral or bacterial disease, or it could be a genetic issue. This can be diagnosed only once the blood report is available," added the zoo director. She added that the second cub is being given antibiotics.

The results from the blood tests carried out by local labs showed an increased leukocyte count in the second cub. An increased leucocyte count implies that there could be an infection in the body. The cub is responding to this treatment but continues to limp, according to Mahajan.

There are six main species of tigers living in the wild today: Siberian tigers, Bengal tigers, Indochinese tigers, Malayan tigers, Sumatran tigers, and South China tigers. Several subspecies of tigers have already gone extinct, including Bali and Javan tigers.

Tigers can also be categorised by their fur colour. White tigers—possibly the most well-known subtype—are produced when tigers carry a rare gene and were first bred in the early 19th century. It is so rare that it only occurs once every 10,000 births.

Tiger populations have been declining rapidly over the last 100 years, with 97% of wild tigers having been lost in the last 100 years.

They are poached for medicinal purposes and for their fur. They are hunted when they stray into inhabited areas as the forests around them shrink, leading prey to become scarce.

It is estimated that tigers have lost 93% of their natural habitat. Climate change is also posing a major threat, with rising sea levels threatening to wipe out even more of their habitat.

white tiger cubs
A white tiger cub looks at a fly in his enclosure at the Attica Zoological Park in Spata, east of Athens Louisa Gouliamaki/AFP