Roughly 4,000 Bengal tigers remain in the wild, spread across India, Nepal, Bangladesh, Bhutan, and small pockets of Myanmar. That number represents a genuine recovery from the low point of the early 2000s, when estimates dipped below 2,000. India alone accounts for the vast majority, with its tiger occupancy expanding by about 30% over the past two decades across a range of roughly 138,200 square kilometers.1Science. Tiger recovery amid people and poverty The rebound is real, but the story behind the headline number is more complicated and more fragile than it appears.
Where Bengal Tigers Live Now
India is the stronghold. The country’s most recent national tiger estimation, conducted in 2022, put the population at around 3,682 individuals across dozens of tiger reserves and the forests connecting them. That figure made India the largest tiger conservation unit in the world, home to roughly three-quarters of all wild tigers on the planet.2PubMed Central. The tide of tiger poaching in India is rising! An investigation of the intertwined facts with a focus on conservation Tigers in India occupy a wide range of habitats, from the mangrove swamps of the Sundarbans in the east to the dry deciduous forests of central India and the foothills of the Himalayas in the north. They also live alongside a staggering number of people: about 60 million share the connected habitats that tigers have colonized outside strictly protected areas.1Science. Tiger recovery amid people and poverty
Nepal has emerged as a notable success story. Its wild tiger population nearly tripled between 2009 and 2023, reaching an estimated 355 animals.3Biodiversity and Conservation. Assessing the aftermath of tripling the tigers’ population in Nepal: socio-economic and eco-environmental sustainability perspectives Nepal was one of the first countries to commit to the global goal of doubling tiger numbers, and it effectively met that target. Its tigers are concentrated in the lowland Terai Arc, particularly in and around Chitwan National Park and Bardia National Park.
Bangladesh’s tigers live almost entirely in the Sundarbans, the vast mangrove forest straddling the India-Bangladesh border. Genetic capture-recapture studies have estimated around 121 tigers in the Bangladeshi portion, at a density of roughly 2.85 tigers per 100 square kilometers.4Global Ecology and Conservation. Using non-invasively collected genetic data to estimate density and population size of tigers in the Bangladesh Sundarbans More recent government censuses have put the count slightly higher, at around 125 adults, suggesting a modest upward trend. These are still small numbers for such a large and ecologically critical forest, and the Sundarbans population faces unique threats that other tiger populations do not.
Bhutan holds a small but scientifically interesting tiger population. Camera-trap surveys in Jigme Singye Wangchuck National Park recorded tigers at densities of about 0.52 individuals per 100 square kilometers, far lower than densities in India’s prime reserves.5Biological Conservation. The use of camera traps for estimating tiger and leopard populations in the high altitude mountains of Bhutan What makes Bhutan unusual is the altitude: its tigers have been photographed at elevations above 3,000 meters, in rugged mountain terrain that was not traditionally considered tiger habitat. Bhutan’s national estimate hovers around 130 tigers, though surveying such remote terrain makes precision difficult.
How Scientists Count Tigers
Tiger population numbers are only as good as the methods used to produce them, and those methods have changed dramatically over the past three decades. Before the 1990s, most tiger counts relied on the pugmark method: forest officials would trace tiger paw prints and try to identify individuals by the shape and spacing of their tracks. This approach was cheap but deeply unreliable, and it almost certainly overstated tiger numbers in many areas for years.
The shift began with camera traps. Researchers working in India’s Nagarahole National Park in the early 1990s demonstrated that individual tigers could be identified unambiguously from photographs of their unique stripe patterns, and that placing cameras along regular travel routes produced enough “captures” and “recaptures” to feed into statistical models originally developed for estimating wildlife populations.6Biological Conservation. Estimating tiger Panthera tigris populations from camera-trap data using capture—recapture models Camera trapping became the gold standard for tiger surveys and remains so today. India’s national tiger census deploys tens of thousands of camera traps across the country.
Genetic methods have added a second layer of confidence. Researchers can now extract DNA from tiger feces collected in the field, identify the species with mitochondrial markers, and then distinguish individual animals using microsatellite markers with better than 99.9% certainty.7PubMed Central. Genotyping faecal samples of Bengal tiger Panthera tigris tigris for population estimation: a pilot study When field-survey protocols for collecting scats are designed to mirror the sampling logic of camera-trap studies, the population estimates from genetic data and photographic data closely agree.8Biological Conservation. Evaluation of non-invasive genetic sampling methods for estimating tiger population size Genetic surveys are particularly useful in habitats where camera traps perform poorly, such as the dense mangrove vegetation of the Sundarbans, where sighting distances are short and flooding regularly destroys equipment.
Both approaches still carry uncertainty. Camera-trap estimates depend on assumptions about how much area each camera “samples” and whether individual tigers have roughly equal chances of being photographed. Genetic methods depend on getting enough scat samples before they degrade. Every published tiger population figure comes with a confidence interval, and those intervals can be wide. Nepal’s 355-tiger estimate, for instance, carries a 95% confidence range of 318 to 392.3Biodiversity and Conservation. Assessing the aftermath of tripling the tigers’ population in Nepal: socio-economic and eco-environmental sustainability perspectives For Bangladesh’s Sundarbans, the genetic estimate’s confidence interval stretches from 84 to 158.4Global Ecology and Conservation. Using non-invasively collected genetic data to estimate density and population size of tigers in the Bangladesh Sundarbans A headline number like “4,000 Bengal tigers” is a best estimate built from many overlapping surveys, each carrying its own margin of error.
What Made the Recovery Possible
India’s Project Tiger, launched in 1973, created the first dedicated tiger reserves, but the real institutional overhaul came decades later. After a crisis in the mid-2000s, when poaching wiped out the entire tiger population of Sariska Tiger Reserve without anyone noticing until it was too late, India established the National Tiger Conservation Authority and the Wildlife Crime Control Bureau. Scientific monitoring replaced guesswork. Technology like the MSTrIPES patrol system, electronic surveillance (E-eye), and drones made anti-poaching enforcement far more effective.9People and Nature. Recovery of tigers in India: Critical introspection and potential lessons
A central strategy was managing tiger reserves as metapopulations: maintaining “source” populations inside well-protected core areas, linked by corridors to surrounding “sink” habitats where tigers could disperse. This approach, combined with incentivized voluntary relocation of human settlements from core areas, expanded the effective space available for breeding tigers.9People and Nature. Recovery of tigers in India: Critical introspection and potential lessons The results are visible in the occupancy data: tigers have not just increased in number inside reserves but have colonized new habitat in the surrounding landscapes.1Science. Tiger recovery amid people and poverty
Reintroduction has worked in at least one dramatic case. Panna Tiger Reserve in central India lost all its tigers to poaching by 2009. Wildlife managers brought in tigers from other reserves and carefully monitored the rebuilding population. Research from Panna highlights an underappreciated lesson: founder populations need enough individuals of both sexes to allow mate choice. When only one male was available, breeding options were limited, but as more males were introduced, females showed clear preferences, and reproductive success improved.10PubMed Central. Tigers in their new territory: intraspecific interactions among the reintroduced tiger population in Panna Tiger Reserve, Central India
Poaching Has Not Gone Away
Despite the recovery, poaching remains one of the most persistent threats to Bengal tigers. Demand for tiger body parts in illegal markets, both domestic and international, keeps the incentive structure alive. India, as the largest tiger range country, faces the sharpest version of this problem. Enforcement has improved, but researchers have described the trend as a rising tide, with poaching pressure intensifying even as legal protections have gotten stricter.2PubMed Central. The tide of tiger poaching in India is rising! An investigation of the intertwined facts with a focus on conservation
Poaching does not just remove individuals; it disrupts population dynamics in ways that can be hard to recover from. Modeling work suggests that poaching substantially affects recruitment, meaning the rate at which new tigers enter the breeding population. Below certain population thresholds, the damage accelerates: a phenomenon called depensation, where smaller populations suffer disproportionately because each lost individual represents a larger fraction of breeding potential.11Natural Resource Modeling. Evaluating feedback dynamics between poaching and population with an application to Indian tigers This matters most for smaller, isolated populations that cannot absorb losses the way a large reserve like Corbett or Kaziranga can.
The Paradox of Living Next to More Tigers
More tigers is good news ecologically, but it has created real problems for the people who live alongside them. Nepal’s tripling of its tiger population coincided with an 11-fold increase in human-wildlife incidents.3Biodiversity and Conservation. Assessing the aftermath of tripling the tigers’ population in Nepal: socio-economic and eco-environmental sustainability perspectives That ratio says something important: the conflict is growing faster than the tigers themselves, likely because expanding tiger ranges push animals into areas where people farm, collect firewood, and graze livestock.
Research in Nepal’s Chitwan-Parsa complex has found that the relationship between tiger presence and conflict is not straightforward. Areas with high human population density had over twice the odds of tiger rescue and relocation events compared to low-density areas. And the worst conflict hotspots were places where both high prey density and high human density overlapped. In those zones, the odds of needing to rescue a conflict-causing tiger were nearly 11 times higher than in areas with low prey use.12PubMed Central. Tiger Habitat Occupancy in Chitwan-Parsa Complex: Implications for Human-Tiger Conflict Management Strategies In other words, the very thing that makes good tiger habitat, abundant prey, also draws tigers into places where they encounter people.
For the households directly affected, the consequences go beyond occasional livestock losses. Studies of communities in tiger reserve buffer zones describe persistent fear, restricted mobility, limitations on livelihoods, and repeated engagement with compensation bureaucracies that acknowledge loss but do not actually reduce the risk.13People and Nature. Living with tigers: Perceptions of risk, equity, and cultural change amidst tiger attacks in a reserve’s buffer zone Conservation success stories that stop at the tiger count miss this dimension entirely.
Corridors and Connectivity
A tiger reserve is only as viable as its connections to other reserves. When reserves become isolated islands of habitat, the populations inside them eventually decline from inbreeding, demographic accidents, or both. Wildlife corridors, strips of usable habitat linking protected areas, are widely regarded as essential for minimizing genetic isolation, enabling dispersal, and restoring ecological processes.14PLoS ONE. Opportunities of Habitat Connectivity for Tiger (Panthera tigris) between Kanha and Pench National Parks in Madhya Pradesh, India
In practice, identifying and protecting these corridors is one of the hardest parts of tiger conservation. In India’s western Terai Arc Landscape, genetic analysis has revealed moderate gene flow between the Rajaji and Corbett tiger reserves, but the migration between these two subpopulations is low and significantly asymmetric. Researchers have concluded that the corridor between them remains functional but could easily lose that status if habitat quality deteriorates further.15PLOS ONE. Fine-scale population genetic structure of the Bengal tiger (Panthera tigris tigris) in a human-dominated western Terai Arc Landscape, India Nepal faces a similar challenge: with tiger populations concentrated in a handful of protected areas along the Terai, the corridors between them pass through densely settled agricultural land.16PubMed Central. Connecting tiger (Panthera tigris) populations in Nepal: Identification of corridors among tiger-bearing protected areas
Carrying capacity within individual reserves also matters. Modeling work at one Indian tiger reserve estimated that its 893-square-kilometer core area could support more than 30 tigers based on available prey, but actually achieving that number would likely require reintroducing females and establishing connectivity with neighboring reserves that have source populations.17Oryx. Could prey support the recovery of a tiger population? Long-term prey density and carrying capacity assessment of a tiger reserve in India Tigers need not just habitat but enough prey within that habitat, and females establish territories whose size and shape are dictated by where prey biomass is concentrated.18Ecological Modelling. Modeling tiger population and territory dynamics using an agent-based approach
The Hidden Problem of Inbreeding
Population size alone does not guarantee a population’s long-term health. Genomic studies of Indian tigers have revealed a clear divide between large, well-connected populations and small, isolated ones. Tigers in small, isolated reserves show substantially higher levels of genomic inbreeding. One study found that an isolated population had an average genomic inbreeding coefficient of 0.57, compared to 0.35 and 0.46 in larger connected populations.19PubMed Central. Genomic evidence for inbreeding depression and purging of deleterious genetic variation in Indian tigers
There is a silver lining in the data, but it comes with a caveat. Isolated populations showed some evidence of “purging,” where the most harmful recessive mutations are weeded out because inbreeding exposes them to natural selection. The isolated population had a lower count of loss-of-function mutations than the larger populations. But those remaining harmful alleles were at higher frequencies and more often present in both copies of a gene. The net result, according to the researchers, was that the small isolated population still showed the highest predicted inbreeding depression of any group studied, despite the purging.19PubMed Central. Genomic evidence for inbreeding depression and purging of deleterious genetic variation in Indian tigers In practical terms, this means isolated tiger populations can appear stable in the short term while accumulating genetic damage that reduces fertility, immune function, and adaptability over generations.
Climate Change and the Sundarbans
The Bengal tigers of the Sundarbans face a threat that no amount of anti-poaching enforcement can address. The Sundarbans are a low-lying mangrove delta, and rising sea levels combined with changing climate conditions are projected to dramatically reduce the habitat available to tigers there. One modeling study projected that by 2070, the combined effects of climate change and sea-level rise would leave no suitable Bengal tiger habitat remaining in the Bangladesh Sundarbans.20PubMed. Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans
That projection, while modeled rather than certain, underscores how different the threat landscape is for Sundarbans tigers compared to their counterparts in India’s interior reserves or Nepal’s Terai. Inland tigers face habitat fragmentation and human encroachment, problems that are severe but potentially reversible with land-use planning. Sundarbans tigers face permanent habitat loss from rising water. The roughly 120 to 125 tigers in the Bangladeshi Sundarbans represent one of the most climate-vulnerable large predator populations on the planet.
Disease as a Growing Concern
Canine distemper virus, or CDV, has emerged as a threat to wild tigers that few people outside the field are aware of. The virus, which spreads through domestic dogs and other carnivores, has already been implicated in tiger deaths in the Russian Far East, where it was identified as an extinction threat to the small Amur tiger population.21PubMed Central. Distemper, extinction, and vaccination of the Amur tiger CDV has since been detected in tigers and leopards in Nepal, raising concerns that it could affect Bengal tiger populations as well.22PubMed Central. Canine Distemper Virus in Tigers (Panthera tigris) and Leopards (P. pardus) in Nepal
The risk is amplified by the same proximity to human settlements that defines modern tiger habitat. Domestic and feral dogs are common in the villages surrounding tiger reserves, and they serve as a reservoir for CDV. For small or isolated tiger populations, even a handful of deaths from disease can be demographically significant. Vaccination of domestic dog populations around reserves has been proposed as a mitigation strategy, but implementing it at the scale needed across South Asia’s tiger range is a logistical and financial challenge that most conservation programs have not yet tackled.
Disease surveillance is still in its early stages for wild Bengal tigers. Most of what researchers know about CDV’s impact on tigers comes from the Amur tiger population in Russia, which is far smaller and better monitored per individual than any Bengal tiger population. Whether CDV has already caused undetected mortality in India’s larger and more diffuse tiger populations remains an open question, and one that the current monitoring infrastructure is not well equipped to answer.