If the latest research data culled by the experts in the forest department, National Tiger
Reservation Project and Wild Life Institute of India are any indication to go by, the big striped cat may be in the process of losing out much of its royal veneer.
Years of evolution, lack of sweet water affecting the height and growth of the mangrove forests, the pressure of tidal waters in the mouth of the Bay of Bengal and the attendant hassle of an arduous search for prey are believed to have taken their toll on the big cat, triggering a genetic mutation, apparently leading to formation of an entirely new sub-species of Panthera tigris tigris (the existing species), researchers have primarily concluded.
All these have not only impacted the height and weight of the tigers in the Sunderbans, but also been contributing to a steady genetic mutation of the tigers in the Sunderbans, according to the experts studying such factors.
For the last few years, forest officials and experts working in the Sunderbans have been observing during the routine job of equipping tigers with radio-collars that these animals are not of the same size and weight compared with those found in other parts of India. The data that has emerged during the latest tiger census carried out in the Sunderbans, reveals that while a proper male tiger on an average, weighs 180 kg (female 160 kg), the Sunderban tigers weigh less, hardly 100 or little over 100 kg.
According to Sunderban Tiger Reserve Director Subrata Mukherjee, the experts’ ‘suspicions’ have come true when a tiger was trapped recently at a place near Sajnekhali. The tiger had strayed into human territory and killed three goats in as many days. The forest staff laid a trap and the tiger was caught.
After a thorough examination, it was found that the completely healthy tiger weighed barely 98 kg while the average weight of the animal of his age ought not to have been less than 140 kg.
Normally, forest officials had earlier found it quite difficult to transport and ferry a caged or tranquilised tiger because of its weight. In sharp contrast, the Sunderban tigers have turned much lighter and smaller in size, points out Mukherjee.
Wildlife scientists and experts have now undertaken a thorough study to explain the latest discovery. “We’re currently analysing various factors; for instance, the mangrove forest in the Sunderbans, the primary habitat of the Royal Bengal Tigers, has lost height. The physiological stress of the tigers has considerably gone up.
They’ve to negotiate swift currents in the tidal waters of the rivers to catch a prey or they’ve to slip themselves through tricky openings while on the prowl. The regular stress and toil might be taking their toll on their built. However, it’s still not clear whether all these have triggered a genetic mutation process,” says Mukherjee.
The latest findings have spurred the experts into wondering whether the process would lead to the birth for a new generation of sub-species of the existing variety. “Scientists in Bangladesh where a large part of the Sunderbans is located, have also noticed an identical change in the structure of the tigers,” claims Pranabesh Sanyal, a very well-known tiger expert.
“Scientists there are of the opinion that salinity level of the rivers in the Sunderbans has been affected due to global warming and lack of sweet water sources which have been affecting the mangrove forest, might be impacting the tiger specie as well in the Sunderbans.”
Such large prey as barasingha and wild buffalo which once used to be the major feed of the tigers in the Sunderbans, has now become extinct. The chital and wild boar on which the tigers depend now, are much smaller in size and hence, the big cat has turned smaller, opines Sanyal.
The officials in the Sunderbans have now collected the blood, hair and seat samples of the trapped animal for its dispatch to the Centre for Cellular & Molecular Biology in Hyderabad for DNA and other tests. The results would reveal whether the environmental and other changes in the Sunderbans have really been affecting the genetic conditions of the tigers there vis-a-vis their counterparts elsewhere in India.
The heavyweights and lightweights
*The Bengal tiger is found primarily in India and Bangladesh. Males in the wild usually weigh 205 to 227 kg, while the average female weigh about 141 kg. However, the northern Indian and the Nepal's Bengal tigers are somewhat bulkier than those found in the south of the Indian subcontinent, with males averaging around 235 kg.
* The Indochinese Tiger, also called Corbett's tiger, is found in Cambodia, China, Laos, Burma, Thailand, and Vietnam. These tigers are smaller and darker than Bengal tigers: Males weigh from 150 to 190 kg while females 110 to 140 kg
* The Malayan Tiger is found in the southern part of the Malay Peninsula.The Malayan tiger is the smallest of the mainland tiger subspecies, and the second smallest living subspecies, with males averaging about 120 kg and females about 100 kg.
* The Sumatran Tiger is found only on the Indonesian island of Sumatra. It is the smallest of all living tiger subspecies, with adult male weighs between 100 and 140 kg and female between 75 and 110 kg
*The Siberian tiger is confined to some areas in far eastern Siberia The largest subspecies of tiger, it has an average weight of around 227 kg for males.
* The South China Tiger males weigh between 127 and 177 kg while females weigh between 100 and 118 kg.