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Tracing tiger’s pugmarks

July 29,2017
Read time: 6 mins

Photo : Vignesh Kamath / Research Matters


“Tiger, tiger, burning bright
In the forests of the night,
What immortal hand or eye
Could frame thy fearful symmetry?
--wrote William Blake, an 18th century English poet, painter, and printmaker, describing the majestic yet elusive tiger…

Today, we celebrate the 7th International Tiger Day, in honour of the charismatic cat, the real ‘king of the jungle’ (since its distant cousin, the lion, doesn’t even live in forests but inhabits vast grasslands). Tigers, the apex predator, and a symbol of ‘the destroyer’ in our lores, our national animal portraying strength and prosperity, the quintessential symbol of the exotic Indian wildlife is now at the humble mercy of man, in need of our protection.

Tigers have burned bright in our forests, in our culture, and in our imagination! Most of us grew up reading the adventures of Jim Corbett and Kenneth Anderson who had to conquer this monstrous predator that had terrorized villagers, by risking their own life. In fact, Corbett is said to have killed 31 man eating tigers during his career as a hunter, rather than a saviour. The Champawat Tiger for instance, the first tiger Corbett defeated, was documented to have killed a whopping 436 people! But of course, these estimates are debated to be a far cry from what a tiger can actually eat, unless it was a super-feaster!

A mistaken man-eater?

Instead of opening a dreadful Pandora’s box of claims versus evidence on these hunted numbers, let’s critically analyze what little we know of tigers. While tigers are portrayed to be courageous and fierce, in reality, they are rather too shy! Thanks to their ability to adapt, they do demonstrate different behaviours based on their environment. You may never see the ‘shyness’ in the tigers of Ranthambore as they now see so many tourists each day! Why? In the 1970s, when tiger population was dwindling, buffaloes were provided for the tigers and were effectively habituated to vehicles, a trait that was picked up by the cubs from the mother.

Unfortunately, this adaptability is what is transforming them into maneaters! Interestingly, most such cases are accidental, or the result of ‘mistaken identity’, where a tiger mistakes a crouching human for a small prey. It may also be because a tiger cannot hunt its natural prey due to its scarcity, or because the tiger itself is injured. It is not a result of the sadistic primal nature of the animal, but a complex behavioural reaction that has intrigued scientists.

But how did this majestic predator end up being at our mercy for protection? It all changed in the last 100 years for the worse. Today, the tiger’s home range has reduced by 93% and its population has fallen from 1,00,000 to just over 3,200! India is home to more than 70% of this number, with one subspecies the Royal Bengal Tiger still surviving extinction. The good news is, their population is on the rise! No miracle of course, but successful conservation programs from ecologists including the establishments of 50 reserve parks for tigers to gain a foothold has served this purpose. Thankfully, India has been blessed not only in terms of the mind boggling biodiversity, but also with people who study and work to protect them.

Counting tiger trails

But how do ecologists estimate tigers and tell us if their populations are on the rise or otherwise? Previously, pug mark censuses were carried out to count them, where a plaster mould of a tiger’s left hind pugmark was collected by thousands of personnel during the same time period of 1-2  weeks all over the country. Laboriously, all four pug marks had to be collected to be able to be able to identify and account for each individual tiger! Ecologists soon dismissed this as an “unsubstantiated guesswork” since the method was riddled with problems - from collecting the correct set of pugmarks, to picking up pugmarks on an unsuitable hard surface.

Here is where Dr. Ullas Karanth’s work in Nagarhole on estimating the tiger population comes to spotlight. In 1995, Dr. Karanth advocated a more mathematical and rigorous approach. He suggested radio collaring tigers and placing a camera to record uncollared individuals. Camera traps -- a camera that takes a photo of an animal when it crosses the path -- were strategically placed along regular routes in a 15km study area. As each tiger’s stripe pattern is unique, the team could identify 10 individual animals from 31 photographic captures without uncertainty over a period of 12 months. This, in turn, was used to calculate the density of the tigers.

The camera-trap technique is not without challenges -- it needs sophisticated equipments, trained volunteers who can identify and survey wildlife, and exceptional statisticians who can crunch the numbers to estimate the tiger population. Hence, it used to calculate absolute numbers of the tiger population in core areas of the reserve. However, for regions that act as buffers or links two or more areas of forest, indirect factors like tiger scat, pugmarks, or scratch marks on trees acts as indicators for size of the population.

At the end of the day, the precise numbers may not really matter! It comes down to knowing whether or not the tiger population is growing. According to the 2016 census report, the population of our tigers has gone up from 3200 in 2010 to 3890 -- a welcome change of course!

But numbers are not just the end of the story. A healthy population of tigers signifies a healthy ecosystem and hence it is imperative that to save tigers, it becomes crucial to work on improving the forest flora, which sustains the prey and in turn, the tiger. But a growing population of tigers also poses challenges as a reserve can only sustain so much. When the numbers go beyond, the tigers start to move into human settlement on the fringes, resulting in human-animal conflicts and relocation of people from forests.

Making way for the growing tigers

Relocation of communities from forests that have been their livelihood for generations and striking a win-win situation for the people and the tiger is a challenge too. This is exactly where collaboration between ecologists and government policies has been monumental in carrying out a successful relocation of 464 families from the Bhadra tiger reserve in Karnataka. Thanks to his work, after relocation, there has been a great improvement in the quality of life for these people as they no longer face water and electricity shortages and live in fear of wild animals, have better access to health care and more employment opportunities. This is also a win for the tigers since with the new land reclaimed, Bhadra is seeing a rise in sustainable tiger population.

While the scientists have been making strides in their work and helping the endangered tiger regain a foothold, it has also become just as important to impart the skills of critical thinking to the public. Today, sale of tiger parts has seen an unprecedented rise, thanks to the the blind belief of the healing power of tiger parts, and has led to a number of tiger deaths - 50 in India alone in the last year. This apart, unsustainable development leading to loss of habitat and global warming are also playing a havoc on their natural habitats, threatening the tiger’s survival.

Before these majestic creatures go into the books of extinct species, perhaps it is time we realised and took steps to conserve them for the future to come!