A leucistic Indian gaur has become the latest animal in the Nilgiris to have been recorded with the rare genetic condition.
Over the last few years, leucism — a condition which causes partial loss of pigmentation and manifests itself in a change in the skin pattern of the animal — has been recorded in two tigers, a Sambar deer, and even a three-striped palm squirrel in the Nilgiris.
This has raised concerns among environmentalists that the fragmentation and isolation of wildlife populations could be driving the prevalence of the condition among species in the upper Nilgiris.
A. Samson, a research biologist at the Bombay Natural History Society (BNHS), who had recorded albinism in a three-striped squirrel in Gudalur and photographed a leucistic Sambar deer in the Nilgiris, said that the genetic mutation that causes leucism, albinism and melanism among wildlife populations could be due to a number of underlying factors.
“The mutation could be caused by a number of factors, including in-breeding, pollution, environmental alterations, low-quality diet or follicular damage,” Mr. Samson said. The expression of these genetic mutations could signify a much more serious problem that needs to be addressed, he added.
“The fact that we are witnessing leucism or albinism among wildlife populations in the Nilgiris is not a good sign. Animals with these mutations may not only be genetically predisposed to contracting certain diseases due to a compromised immune system, but also face the prospect of having a reduced chance of survival in the wild due to a lack of camouflage,” he explained.
“Lack of genetic diversity among mating populations of a species is a major factor behind leucism and albinism among wildlife,” said B. Ramakrishnan, assistant professor at the Department of Zoology and Wildlife Biology of the Government Arts College in Udhagamandalam.
“The upper Nilgiris is primarily comprised of 80% grassland and 20% Shola forests. With grasslands being destroyed, corridors connecting different habitats and populations too have been disturbed, and in many cases, completely severed,” Mr. Ramakrishnan said.
Such disruptions to existing habitats have accelerated over the last few decades.
“As populations of wildlife have become more isolated, it would not be a surprise to learn that there is a lot of in-breeding taking place, resulting in these mutations,” he said. The only way to ensure genetic diversity was to restore destroyed wildlife corridors, which will facilitate the mixing of different populations, he said.
Forest Department officials in the Nilgiris division said that more research was needed to determine whether there was a higher rate of leucism or albinism manifesting in wildlife populations in the upper Nilgiris. “It could be that this particular expression of leucism is just a genetic mutation,” a top Forest Department official said.
