ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[peter]

(10-30-2014, 10:51 AM)'GuateGojira' Wrote: It is clear to me, that Bengal tigers had been of the same size and weight trough all this time. There is no difference (except for a few giant specimens). Large tigers existed and large tigers are still here. There is no "they were larger" or "they are now larger". The variations reported are based more in bad guesstimates, wrong old measurements or just geographic variations. The only population that suffered a dramatic change was that of The Sundarbans, but we most take in count that all the tigers captured in this area were frail and underweight, except for an old (12 years old) female of 80 kg, which was described in good condition (but check her age).

Between 100-150 years ago, male tigers averaged 402 lbs. in the Deccan, 420 lbs. in Central India, 435 lbs. in North-India and 460 lbs. in Assam, Cooch Behar and the Duars. If we disregard other regions and give each region a similar 'weight', the average works out at 430 lbs. for India roughly.

But.

The Deccan sample was small and had two tigers well below 400 lbs., which had a profound effect on the average. Dunbar Brander, regarding Central-India, lost most of his notes (his average referred to 42 males, but he had shot over 200). Furthermore, he missed a few large tigers. Hewett's sample also was affected by a number of young adults (3-4 years of age). Besides, he wasn't able to weigh twelve very heavy tigers because his scale had to be repaired at regular intervals. And the sample of the Maharajah had seven 'gorged' tigers. Without them, his average would have been 453 lbs. All in all, one could say the range probably was more limited, whereas the middle values (420 and 435) were too low. Based on the data I have, I concluded the real average could have been between 435-450 lbs. or thereabout. This average relates to the first decades of the last century. 

But half a century earlier, males in Central-India, according to Hicks, Forsyth and plenty of other with a lot of experience, ranged between 450-500 pounds. If we, as a working hypothesis, accept both averages (475 lbs. a century and a half ago and 445 lbs. about a century ago) were about correct, they could reflect the deterioration in conditions rather than the actual size of tigers.   

There isn't much on today's tigers. Of those weighed in the last four decades, however, not one was under 400 lbs, whereas a significant percentage was over 500 lbs. My guess for now would be 470-480 lbs. Slight advantage (5-10%) today's tigers, that is.  

Why is that?

One reason is the old samples were smallish. Another reason is adolescents and young adults (the Deccan and North-India) as well as gorged tigers (Assam and Cooch Behar) were included. And in Central-India, notes were lost. We could go for a lack of accuracy as a result of different reasons and be close. That, however, still wouldn't quite explain the difference between then and now. That's why we have to include 'conditions'. A century and a half ago, tigers were not that far away from pristine conditions. Half a century later, it was downhill all over India. Today's tigers, although very low in numbers, live in well-stocked reserves. The problem is they face stiff competition and infighting, because young males, for lack of room, can't disperse. These two factors could have resulted in larger-framed and, therefore, heavier animals. Maybe the tigers living in well-stocked reserves today compare to those that lived in near-pristine conditions a century and a half ago.  

Problem solved.

As for exceptional animals. It is to be expected a large population will produce more exceptions than a smaller one, especially in large animals like tigers. We were not disappointed in that reliable data indeed confirm there were more exceptions a century ago and even more a century and a half ago. Again no problems. Except for credibility, but that is a factor which should have little 'weight'.

Everything I know suggests wild tigers quickly adapt to circumstances. This, In think, is the main reason they deteriorated about a century ago. In the last three decades, in some regions, conditions have improved to an extent. It starts with territory. Expressed as a percentage of total land use, forests have increased considerably in India (from 19% three decades ago to about 24% today). There are now more reserves and wildlife is on the agenda again. The result is conditions have improved. The tiger responded. My guess is we will see a similar development in Russia and north-east China: more forests, more protection, more large animals, more tigers and, in the end, larger (heavier) tigers, resulting in a higher average.

It also works the other way round. Tigers living in regions subject to violent, human-triggered, changes lose size. As soon as humans move in, large prey-animals disappear. When they go, tigers target cattle first and humans later. The result is an even more intense hunt. The war-like situation, with both parties behaving like terrorists, continues until one is gone. The only thing missing is secret sponsors and reporters. The war usually goes unnoticed, but Sumatra tigers succeeded in attracting attention. Nearly every photograph of a captive Sumatran 'problem-tiger' shows an angry tiger. I never saw more angry tigers than Sumatran tigers.

Everything we do has consequences. Same for this forum. It is about animals. Big cats foremost. The more we talk about them, the greater the chance it will have some impact in the end. Spread the word:

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