were all related – mothers, daughters, aunts and nieces –
much like lionesses in a highly dispersed pride.
A daughter would probably be able to land-grab remote
parts of her mother’s range when they became temporarily
unoccupied while the mother was tied to the core den area
by a new litter. This ability to settle in a familiar landscape
offers a huge survival advantage for females. Intimate
knowledge of the lie of the land, of where and when prey
is concentrated, and of how tracks, forest clearings and dry
riverbeds connect to provide highways and stalking routes –
these things can decide whether a predator eats or starves.
All this is denied to male tigers. They must travel far afield
to convey their all-important gene package to strangers.
Exiled from the familiar hunting grounds of home, the
wandering males suffer three times the mortality rate of
females of similar age.
The Smithsonian study found that, even if he makes it
to the top, an adult male’s average period of dominance is
a mere 32 months. Furthermore his lifespan is several years
shorter than that of a female. No wonder adult male tigers
are in such a hurry to mate.
Indeed, the Smithsonian and subsequent studies have
shown that mating is about the only thing on an adult
male tiger’s mind. He doesn’t fight over food or notions of
territory, but only for access to a female in oestrus. This even
affects a male’s attitude to hunting.
Raghu Chundawat’s study of tigers in the dry forests of
Panna National Park in Madhya Pradesh showed that adult
tigresses were mostly cautious hunters, avoiding human
landscapes and concentrating on natural prey rather than
cattle. Dominant males, on the other hand, always on the
move between females, took their meals where they could –
nearly 90 per cent of them from domestic livestock.
The selfish gene explanation
may favour the opportune, the
lucky or the sneaky, but that is
not to say there is no role for the
fittest. David Smith still inspires
listeners with his memories of
Tiger 105. Weighing over 225kg,
this was the biggest tiger his
team ever handled. Dominant for
six years in the 1970s, Tiger 105 ranged over 120km^2 , with
exclusive access to seven different females. He sired 51 cubs,
of which 27 survived to disperse. In the two years following
his death there were frequent fights and infanticides, and only
five cubs survived in the whole region. Tiger 105, fittest of
all, ensured a productive era of stability for the females and he
must have made a huge contribution to the gene profile of
tigers in Chitwan today.
All this destruction of cubs and expensive production of
males doomed to wander and mostly die in the name of sexual
reproduction is very wasteful. At present, we can’t be sure why
this system has evolved. But we can only guess and hope that,
somehow, the losses we rue – including that small cub in the
sal forest of Madhya Pradesh – are helping to safeguard the
genes, and future, of the species.STEPHEN MILLS is a writer and film-maker who has been watching and filming tigers
for over 25 years. He also leads wildlife tours, and has visited India more than 40 times“An adult male tiger’s
period of dominance
might be a mere 32
months – no wonder
he’s in a hurry to mate”
The ground-breaking Tiger Ecology
Project at Chitwan National Park
documented one phenomenal tigress
with a reproductive lifespan of 12.5
years that reared a total of five litters,
and another remarkable ‘super mum’
that produced four litters over 10.5
years. But female tigers as successful
as these are far from the norm. A
tigress will typically live for perhaps
8–10 years in the wild, somewhat
longer than an adult male, and breedfor the first time at between three and
four years old, giving a reproductive
lifespan of closer to six years. And
even these figures are deceptive,
since they suggest that a female will
raise far more young than is actually
the case. The Chitwan study found
that, on average, a tigress in the park
could expect to nurture no more than
four or five young to independence,
and, of those, only two tigers would
themselves get to breed.SUPER MUMS
A female suckles three
cubs in Bandhavgarh