The Bengal tiger (Panthera tigris tigris)

The Bengal tiger (Panthera tigris tigris) is the most numerous tiger subspecies in Asia, and was estimated at fewer than 2,500 individuals by 2011. Since 2008, it is listed as Endangered on the IUCN Red List and is threatened by poaching, loss and fragmentation of habitat. None of the Tiger Conservation Landscapes within its range is considered large enough to support an effective population of more than 250 adult individuals.[1]

The tiger arrived in the Indian subcontinent about 12,000 years ago.[3] India's tiger population was estimated at 1,706–1,909 individuals in 2010.[4] By 2014, the population had reputedly increased to an estimated 2,226 individuals.[5] Around 440 tigers are estimated in Bangladesh, 163–253 tigers in Nepal and 103 tigers in Bhutan.[6][7][8][9]

The Bengal tiger ranks among the biggest wild cats alive today.[2][10] It is therefore considered to belong to the world's charismatic megafauna.[11] It is the national animal of both India and Bangladesh.[12]
Bengal tigers weigh up to 325 kg (717 lb), and reach a head and body length of 320 cm (130 in).[20] Several scientists indicated that adult male Bengal tigers from the Terai in Nepal and Bhutan, and Assam, Uttarakhand and West Bengal in north India consistently attain more than 227 kg (500 lb) of body weight. Seven adult males captured in Chitwan National Park in the early 1970s had an average weight of 235 kg (518 lb) ranging from 200 to 261 kg (441 to 575 lb), and that of the females was 140 kg (310 lb) ranging from 116 to 164 kg (256 to 362 lb).[21] Thus, the Bengal tiger rivals the Amur tiger in average weight.[22]

Verifiable Sundarbans tiger weights are not found in any scientific literature. Forest Department records list weight measurements, but all are guesstimates and not verifiable. There are also reports of head and body lengths, some of which are listed as over 366 cm (144 in). More recently, researchers from the University of Minnesota and the Bangladesh Forest Department carried out a study for the US Fish and Wildlife Service and weighed three Sundarbans tigresses from Bangladesh. Two of them were captured and sedated for radio-collaring, the other one had been killed by local villagers. The two collared tigresses were weighed using 150 kg (330 lb) scales, and the tigress killed by villagers was weighed using a balance scale and weights. The three tigresses had a mean weight of 76.7 kg (169 lb). One of the two older female's weight 75 kg (165 lb) weighed slightly less than the mean because of her old age and relatively poor condition at the time of capture. The teeth wear of the two radio-collared females indicated that they were between 12 and 14 years old. The tigress killed by the villagers was a young adult, probably between 3 and 4 years old, and she was likely a pre-territorial transient. Skulls and body weights of Sundarbans tigers were found to be distinct from tigers in other habitats, indicating that they may have adapted to the unique conditions of the mangrove habitat. Their small sizes are probably due to a combination of intense intraspecific competition and small size of prey available to tigers in the Sundarbans, compared to the larger deer and other prey available to tigers in other parts.[23]