Odisha's mysterious tigers: Why do melanistic big cats have darker appearance

Similipal Tiger Reserve is the world’s only landscape with melanistic tigers, a rare variant of the Royal Bengal Tiger. TOI’s Riyan Ramanath explains this special breed of tiger present in Odisha’s deep jungles

Chance discovery
The presence of melanistic or black tigers was always shrouded in mystery and the first discovery in the form of a sighting was made in 1975, but the breed was confirmed only in 1993 when remains of a poached black tiger were found deep inside the Similipal forest. In 2007, the first camera trap picture of a black tiger was obtained. Wednesday’s discovery of a melanistic tiger poaching is a first since 1993.

Physical appearance
They have more black pigmentation/ stripes on their body than the normal colour. They exhibit a unique coat pattern due to a genetic mutation that increases melanin production, resulting in thicker, more pronounced stripes that often merge giving them a darker appearance. Growth of melanin increases the width of black stripes thus making the animal look different from the normal Royal Bengal Tiger.

Genetic basis
Wildlife experts say melanistic tigers have different genes. The black tigers have thick stripes so close together that the tawny background is barely visible between the stripes. The most likely reason why this happens is due to mutation in the genes of tigers.

Taxonomic classification
A combination of these factors — a small founding population, isolated habitat, inbreeding, and genetic drift — are the likely evolutionary forces that have created Similipal’s unique population of black tigers.

Population status
Similipal Tiger Reserve (STR) has 13 melanistic tigers — seven females and six males — out of an estimated 35 Royal Bengal Tigers, according to a census conducted by state govt. There are, however, at least eight black cubs, whose presence in the 2,750sqkm radius is yet to be confirmed.

Protection
After Bandipur National Park in Bengaluru, Odisha’s Similipal is the country’s second to have a dedicated Special Tiger Protection Force (STPF) formed in 2013. In 2023, exservicemen were engaged in protection and govt provided them with firearms last year. Conservation efforts are ongoing to protect these rare tigers. National Tiger Conservation Authority recently approved melanistic tiger safari at Baripada in Mayurbhanj district.