ntified the timing and extent of demographic decline, and simulations revealed a relatively recent decline (158 years ago, Figure S6, Figure S7, and Figure S8) of about the same magnitude (90%) as for Central and South Indian tigers. However, the median ancestral effective size for Indochinese tigers was much lower than that of the Indian tigers in central and south India (23,280). The higher ancestral effective size explains the higher genetic variation among extant Indian tigers inspite of recent, human induced decline.
Data from mitochondrial DNA potentially reveal a signal of demographic expansion, while microsatellite data reveal a signal of a recent population decline. The strong population differentiation for mitochondrial DNA (Table 2) could also result in the observed, expansion-like pattern  and the resultant high mitochondrial genetic diversity in this part of the species' range.
Our genetic data in combination with a series of simulation models suggests that prior to historical human impacts, the genetic effective population size for tigers from peninsular India was between 2,964 and 151,008, with a median value of 23,280. Converting this effective population size into a population size suggests that between 7,412 and 377,520, with a median of 58,202 (using Ne/N = 0.4 , where Ne is the effective population size and N is the census size) adult wild tigers inhabited peninsular India prior to these human impacts. Given the recent census estimate of around 1,000 adult tigers in peninsular India , this corresponds to a median decline of approximately 98% over the last 200 years. Major demographic declines are evidenced by historical hunting records (based on bounty killings) during the Colonial rule, which suggest that over 80,000 tigers were hunted for bounties between 1875 and 1925  across the Indian subcontinent. These data potentially indicate an even higher historical population size for tigers than do our results. However, the demographic decline we detect is in the face of high potential annual growth rates , suggesting that hunted individuals far exceeded 57,000 (98% of the ancestral effective size), even in peninsular India. Accounting for population growth rates suggests that our genetic results might be in concordance with historical hunting records. Our estimates of the decline are linked to the assumed Ne/N ratio of 0.4 . Empirical estimates for mammals suggest a median Ne/N of 0.6  while theoretical estimates suggest Ne/N of 0.5 . These estimates would reduce the decline to 97.4% and 97.8% respectively. Alternatively, Ne/N values lower than 0.4 would accentuate the decline scenario we propose.
It is known that in the last ∼600 years, two major historical events  affected tiger populations across the Indian subcontinent: the intrusion and political control of India by Mughal' warriors who were known for their advanced hunting technologies, and subsequently, the establishment of the British Empire, which promoted widespread use of fire-arms, modern technologies and encouraged mass hunting of tigers for bounty and sport. Our results estimate the median timing of decline to 200 years ago, overlapping with the extensive bounty killings, which started around 130 years ago under colonial rule . Historical records indicate that tigers were systematically hunted from Mughal times (around 500 years ago, ) and the subsequent colonial rule additionally encouraged bounty-hunting (initially in eastern India) from about 1777 (231 years ago) . It is possible that tiger population declines started during the Mughal empire and accelerating over the last 150 years during colonial rule. The analytical approaches we use in this paper explore relatively simple scenarios of decline. However, additional historical genetic data from trophy or bounty hunted tiger skins might allow investigate as to whether rates of decline in tiger populations have increased relatively recently. Finally, our estimates of the timing of decline are based on an assumed 5-year generation time for tigers . A higher generation time (say 6 years) wo