Genetic rescue

Odisha to introduce two female tigers to Similipal forests to improve genetic diversity of its melanistic tiger population

- HIMANSHU N

FOR DECADES, dense forests of the Similipal Tiger Reserve in Odisha have been home to a unique population of melanistic tigers. These rare big cats, distinguished by their thick, dark stripes that often merge into a “black” appearance, have roamed freely here. The reserve is the only habitat in the world where these pseudomelanistic tigers are found, making it a stronghold for their conservation.

Despite their rarity, a rise in the population of these pseudo-melanistic tigers in recent years has sparked concern of inbreeding depression, a condition where animals can experience reduced fitness and increased susceptibility to diseases, eventually leading to population decline or extinction.

In an effort to boost genetic diversity and avoid inbreeding, the Odisha forest department plans to introduce two new female tigers to the reserve. If successful, this will mark a significant step in safeguarding the long-term health and viability of Similipal’s unique tiger population.

In the “All India Tiger Estimation-2014”, the reserve recorded five tigers, of which only one was male. “The lone male tiger was pseudomelanistic and it mated with other female wildcats, thus transferring the trait,” says Prakash Chand Gogineni, field director at Baripada forest circle in Odisha.

By 2024, tiger number in the reserve grew to 24 adults, as per the “All Odisha Tiger Estimation 2023-24”, released by the state’s forest and environment department this February. Of these, 13 are pseudo-melanistic, with six males, states the report. “This means almost 60 per cent of the current population exhibit melanism,” says Gogineni. A 2020 study published in the Proceedings of the National Academy of Sciences identifies a mutation in the Taqpep gene (Transmembrane Amino-peptidase Q) as responsible for this pseudomelanism, likely because of the genetic isolation of the population.