A brief introduction to the Tiger…
Tigers are part of a group of large cats that come under the name of Panthera. Tigers (Panthera tigris) are the largest of the big cats, but there is some size variation across their range. I often hear people saying that the Royal Bengal Tiger “is the largest, most cunning and ferocious tiger!”. In fact there is only 1 species of tiger in the world and 8 sub-species, of which the Royal Bengal Tiger is 1. Three of the 8 original sub-species are already extinct. Tigers in Bangladesh share many common characteristics with all other tigers, even if those tigers live in different countries and forest types.
The largest tigers on record come from central India and Nepal, the smallest from the Island of Sumatra and the Sundarbans. Male tigers are larger than females; an adult male in Nepal might weigh 200-250 kg + but an average female will be 150 kg. The first collared tiger in Bangladesh (Jamtola Rani) was only 75 kg, although her old age might have accounted for her slight build.
The animals that we recognize as tigers are thought to have first evolved about 2 million years ago in East Asia. Evolution occurs by natural selection, a term that refers to a process that leads to the accumulation of advantageous characteristics in a population. . In any population there will be variety in any characteristic, for example height or color etc. When a characteristic (like a claw length, coat pattern, tail length etc) gives an animal an advantage over others, then that animal has a better chance of surviving and passing on that characteristic to its offspring. In this way a particular characteristic can become more common over time. From East Asia, tigers started to move across the rest of Asia following the large deer and cattle species which dispersed at that time. The tiger is a specialist hunter of large hoofed animals. Its large canine teeth have been designed to inflict a killing bite to its prey, with the rest of its teeth adapted for holding and cutting through flesh. The claws are used for catching and controlling its prey. The stripes help keep the tiger hidden from watchful deer and monkeys, and its powerful body lets it make fast dashes to catch its food, after a long stalk gets it within range. Tigers only eat meat, normally getting most of their food from large to medium size wild cattle, deer and boar. However, they are opportunists that will eat most types of flesh if they get the chance.
Tigers now live in a very small fraction of their former range. At present there are still wild tiger populations in India, Bangladesh, Nepal, Bhutan, Thailand, Cambodia, Vietnam, Laos, Burma, China, Russia, Malaysia and Indonesia. Tigers occupy a wide variety of forest types; for example in Russia the forest is very open and the ground is covered in snow through the winter months, whereas in Nepal they live in more humid conditions, occupying a mixture of grassland, riverine and moist-deciduous forest. There are now only about 5,000-7,000 wild tigers remaining. There are probably many times more people living in your local town then there are tigers left in the wild. Many tiger populations are small (less than 50 breeding adults), which makes them all the more vulnerable to poaching, disease and environmental catastrophes.
For a long time, the biggest threat to tigers was destruction of the forest. In the last 100 years or so, the forest cover, and therefore the space available for tigers, has been greatly reduced. Although in many countries this deforestation has slowed down or stopped, the tigers are far from safe. Poaching in particular, is a huge problem in many areas. There is a high price on the tigers’ head driven by a demand for products made from its different body parts. Some people still want to use tiger bones for medicinal use and the skins are still marks of wealth in some places. Much of the demand comes from markets in China, Taiwan, and South East Asia.
There are very few tigers left in China these days, so many tigers are now poached in India and smuggled into China through Nepal over high mountain passes. In Bangladesh, poaching seems to be at relatively low levels at present but this can change quickly. If tiger numbers in India decrease to the point where hunting becomes too difficult, then the highly organized poachers may shift their activities to the Sundarbans. Tigers are not anyone’s property, they have a right of their own to exist and their presence helps nature function properly and the world a more beautiful place.
If a tiger becomes habituated to killing man or cattle and no action is taken by the authorities, then local villagers will sometimes kill the tiger by poisoning or shooting. If this is not dealt with promptly then animosity towards tigers will grow and needless loss of human and tiger lives will continue. Learning about how tigers live and what sign they leave behind in the jungle will give some of the skills you need to start dealing with these problem animals. Tigers can also be killed indirectly. Poaching of deer and wild boar is taking food out of the tiger’s mouth. The amount of deer and other food available will determine how many tigers can live in a particular forest type. Also, some of the methods used for catching deer, like snaring, can inadvertently catch and sometimes kill tigers. There is a photo of a tiger in Nepal that had got caught in a deer snare. Skin and flesh had been ripped from the tiger’s flanks as it struggled to escape and the wire loop of the snare can still be seen wrapped tightly around its stomach. The tiger undoubtedly died a long and painful death as it gradually succumbed to its injuries.
It is also important to remember that everything in nature (atmosphere, rivers, trees, birds, insects, fish, reptiles and tigers etc) is connected; polluting or destroying one part of it, will weaken the rest. Companies allowing their factories to pump toxic chemicals into the river, are killing the sundarbans as surely as the deer poacher or illegal woodcutter.
Tigers are generally solitary and reclusive animals that shy away from human contact. Adult tigers hunt and live alone, only meeting for mating purposes or to fight. Tigers will sometimes fight because there is a limited space for all the tigers to live. Tigers are territorial, which means that they spend considerable time and energy defending an area because it contains an important resource necessary for their survival. Females defend a patch of forest that has enough prey to support themselves and any cubs they may produce. Although there may be a small degree of overlap, resident, breeding females will defend their patch of forest from other females. Because a female is basically defending food, the size of a female’s home range will be a good reflection on how much prey is available in a particular forest type. For instance, in Nepal, females have home ranges of 15-20 km2, but in Russia, where prey density is lower, a female can have a home range of over 400 km2. It is not in a female’s best interest to protect less area than she needs, because she will not be able to feed herself or her cubs properly. Likewise, if she defends more area than she needs, then she is wasting precious time and energy, as well as inviting more pressure from other female tigers who also want a territory of their own.
A male, on the other hand will try to get a territory that contains as many female territories as possible. In doing so, the male is protecting his breeding rights over these females. He spends a lot of time patrolling to make sure other males don’t come in. It will be slightly different from place to place, but a male tiger’s territory may cover 2-5 breeding females (3).
Both sexes will leave signs to warn other tigers not to enter their territory. All over its territory, but particularly on its borders, the tiger will spray trees and leave scrapes on the ground as visual and olfactory (smelly) signs of their presence. The female’s spray may also give information to a passing male about if she is ready to mate.
Tigers can be active at any time but they generally rest during the day and patrol and hunt during the hours of darkness. They have excellent hearing and good eyesight that helps them detect their prey in the dense mangrove forest.
They will spend a lot of time stalking their prey before a final rush from close range. Hunts are very often unsuccessful because the prey can sometimes smell, hear or see the tiger before it gets too close. If a tiger manages to make a kill it will continue to feed on it until only some bones and a few scraps of skin remain. During the day a tiger will generally lie up in thick vegetation close to its food, returning to it when darkness starts to fall.
Tigers do not in general prey on man but some can turn into man-eaters. There is an important distinction though between tigers that kill humans by accident or out of defense, and “man-eaters” who actively seek out humans to kill for food. Why a tiger becomes a man-eater is not well understood. In some cases a tiger might kill a human if it feels threatened or when it is defending its food or cubs. In other cases it may be that the tiger is very old or has acquired some injury that stops it from hunting its normal prey. There may also be individual tigers that are just naturally more aggressive than others.
Female tigers give birth to 2-4 cubs after a 100-104 day pregnancy. The cubs are very small when they are born and for the first 10 days or so cannot open their eyes. For a long time they are totally dependant on their mother. It will take around 6 months before they stop taking their mother’s milk and move on to eating meat. The cubs stay with their mother for 18 months to 2 years. During that time they develop the necessary hunting skills they will need when they have to fend for themselves. Before it is time to leave their natal area, they will be similar in size to their mother if they are female and larger if they are male. This explains some reports of people seeing 3 or 4 “adult” tigers together at one time in the Sundarbans. These 3 or 4 “adults” are in fact a mother and her large cubs, all still living together. When the cubs (now sub-adults) leave, they have a dangerous time ahead of them as they try and find a place of their own to live and reproduce. When the cubs leave, the mother will produce a new litter of cubs.
Neither males nor females will reproduce without first acquiring a territory. If a new male takes away a territory from the previous resident, he will try and kill all the old male’s cubs so that he can mate with the females as soon as possible. Females normally start reproducing from between 3 and 4 years of age and males don’t generally get big and strong enough to get a territory of their own until they are about 5 years old. Although they live longer in zoos, the oldest wild tiger on record was a female from Nepal that lived until she was 17. Many tigers die young while still cubs. More die after they leave their mother’s territory and before they get a territory of their own. During this time when they are searching for a new territory they are called transients. If they do go on to get a territory they have a very limited time in which to produce offspring; breeding females live until 7-14 years old and males until 6-12 years old. If the tiger becomes injured or too weak to defend its territory or catch its normal prey, then that tiger will die after a very short time. Such a tiger may also be more likely to come close to villages to kill cattle or sometimes people.