Stalking Tigers Through Time
Tigers have stalked the Earth for millennia. Learn how time has shaped these graceful cats – before it runs out.
By Karyl Carmignani, Staff Writer SDZG;
Photos by Ken Bohn, SDZG Photographer
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"There is no off switch for a tiger"
With their sleek, muscled bodies, claws on every paw, and a mouthful of dagger-sharp teeth, cats of all persuasions are deft at bringing down prey and defending themselves.
From the pint-sized fur ball purring on your lap to the fleet-of-foot cheetah chasing down her supper to the stealthy and mighty tiger, all species of the modern Felidae family diverged from a common panther-like predator in Asia more than 11 million years ago. A few million years later, the lineage split into two subfamilies: Felinae, the small and medium-sized wild cats, including the cougar and cheetah, and the larger cats of the Pantherinae subfamily, including the lion, jaguar, leopard, and tiger.
These mighty hunters radiated out across the land around 3.7 million years ago, diverging along the way and leading to the present-day Panthera genus.
The earliest tiger fossils, discovered in northern China and Java, Indonesia, date back about two million years. In the last 100 years, we have lost 97 percent of wild tigers. Before these iconic cats become but a dusty memory, it is imperative we learn all we can about them to better manage and conserve them.
(Picture shows a Malayan Tiger.)
Time in a Bottle
It can be difficult for humans to grasp vast spans of time like “millions of years”, given our puny (in evolutionary terms) life spans that rarely exceed 100 years.
But ecological pressures and opportunities can exact great change over gigantic slabs of time. Much of the origin and evolution of tigers (or anything else, for that matter) relies on fossil evidence and educated conjecture among paleontologists, anthropologists, morphologists, and geneticists. There are missing pieces, but with each passing year and technological advance, more insight and a deeper understanding of ancestry, lineages, and radiation are added to the scientific tome.
Tigers were once widespread across Asia, from Turkey in the west to the eastern coast of Russia and as far south as the Indonesian islands of Bali and Sumatra.
Hunting prowess and a flexible meat-based diet enabled them to fill varied niches. But according to some scientists, the disastrous volcanic eruption of Toba in Sumatra about 73,500 years ago let to a volcanic winter that persisted for several years, followed by a thousand years of a cold, dry climate. It is thought that the cataclysmically cooled climate contributed to a massive reduction in the range of tigers.
In more recent times, tigers have suffered mightily at the hands of humans. In the past century alone, the tiger has lost more than 93 percent of its historical range, and 3 tiger subspecies (Bali, Javan, and Caspian) are now extinct. Today, the six remaining subspecies hang on by a whisker in scattered isolated populations in 13 countries. (The South China subspecies is thought to be extinct in the wild, and there are fewer than 80 individuals remaining in captivity.)
Where Tigers Roam
Past and present...
Sizing Them Up
Powerful and burly, tigers are arguably the largest and strongest of the big cats.
They can take down prey five times their own weight. With no need for assistance from pack members, these solitary hunters rely on the element of surprise and a burst of speed to capture their next meal.
There is some size variation among the six tiger subspecies, but it follows more of a gradient rather than abrupt differences. Tigers from southern latitudes, like Sumatra and other Indonesian islands where it’s warmer, tend to be smaller than their northern brethren. Adult males in tropical areas average 8 feet in length, while males from northern climes can reach nearly 11 feet in length.
Amur (formerly known as Siberian) tigers from the Russian Far East have long been thought to be the largest subspecies, but recent measurements indicate they are, on average, neck and neck with the Bengal tigers of India, Bangladesh, Nepal, and Bhutan. Female tigers of all subspecies are about 20 percent smaller and lighter than the males, and studies show their prey is also somewhat smaller than what the males take.
Panthera and People
The tiger is highly esteemed, admired, and often feared.
Seeing one of these striped creatures close up as it rears on its haunches and lets out a roar can leave one shaken and deeply moved. Tigers can slink past silently – their striped, orange coat helps them sink seamlessly into the forest. In 1973, the first radio-tracking study of tigers occurred in Chitwan National Park, Nepal. A researcher from the Smithsonian Tiger Ecology Project later recalled how he “watched and listened in horror as more than 100 people walked down a trail, practically within touching distance of a radio-collared tiger feeding on a kill.” This was not an uncommon occurrence.
Living Side by Side
Tigers have learned to live within striking distance of humans.
Even though we would be easy prey for them, tigers typically do not include humans on their menu, plentiful though we may be. The big cats that have eaten humans were found to be old or injured and unfit to bring down their usual fare; in India, tigers kill 40 to 60 people each year. Tigers are ambush hunters, with only about 1 in 10 hunts resulting in a meal. If a human looks at a tiger, it is supposedly less apt to attack as it has lost the element of surprise. Hence in some areas of India, people wear a mask of a face on the back of their head while working in the forest to “fool” tigers and prevent them from pouncing from behind.
A Sumatran tiger female is play-chased by her nearly grown cubs.
Habits and Habitats
Big cats require big meals.
Research indicates a strong correlation between the abundance of large ungulates and tiger densities. Prey availability determines carnivore territory size, energy expenditures, the density of breeding females, the number of “transients,” and the survival of cubs and juveniles. Tigers can go several days without eating, and then they gorge themselves. Due to their robust size, however, they can starve to death in a mere 2 to 3 weeks, while humans can stay alive without food for 30 to 40 days. Tigers are apex predators across their wide range of habitats, which includes tropical rain forests, evergreen forests, mangrove swamps, grasslands savannas and temperate forest. They need dense vegetation, access to water, and large ungulates to survive. Poaching and habitat loss remain the largest threats to all tigers and humans hold the key to correct both hazards. Will humans evolve in our thinking and behavior rapidly enough to save them?