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The above extracts clearly establish the causes of reduction of tigers during
the nineteenth century. The extract at (c) will indicate that the area that now
forms Greater Bombay had in the eighteenth century its share of tigers,
including man-eaters. The extract at(h), which mentions Koyna valley as a
haunt or tigers, underlines another cause of reduction of wild life; the valley
is now a lake due to construction of the Koyna dam. Such storage reservoirs,
in remote forest areas, have also led to depletion of wild life, but this is
inevitable.
10.Tiger population.— Let us consider statistically the variation of a tiger
population, and the factors involved. It is obvious that the only addition to a
given tiger population in an isolated region can occur solely by survival of
cubs; and that over a period of years, the population will decrease if the
number of deaths from all causes exceeds the number of cubs surviving to
adulthood. Normally tigresses start to breed at the age of 3 years and may
breed every other year, until about the age of 13 years. It is known that after
the age of about 14 years, wild lions do not survive, because having blunt
teeth and/or lacking the strength to hunt or having other infirmity, they are
killed by hyenas wild dogs etc. The same upper age limit may reasonably be
held to apply to tigers also. A tigress which in season seeks the male, would
thus breed, during her reproductive age about 4 or 5 times, assuming no
dearth of male tigers for mating. The number of cubs in a litter is usually 3 to
4 but cub mortality is high, due to hyenas, wild dogs, birds of prey and even
ants, apart from disease, and poachers. The size and frequency of litters of
course depend on stress of living and availability of food and must be
affected by 'disturbance' referred to in para. 7 above. Two cubs may thus
reach adulthood safely, and start hunting on their own. Even at this stage,
casualties occur, owing to inexperience or ineptitude of the probationer and a
young tiger may suffer death when trying to kill formidable animals like the
wild boar, buffalo, etc. It may be assumed that one tigress in course of her
reproductive life span of 10 years will make an addition of not more than
about 10 cubs, i.e. the average addition is not more than one cub per year per
tigress of reproductive age. On the debit side we have to take account of
many factors such as disease, disabling injuries, in addition to the tigers
killed by poachers or poisoned, shot on permits or by V.I.Ps. and dignitaries
and the ancillary loss connected with such shoots, as stated earlier. It will
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