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

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GuateGojira Offline

Expert & Researcher

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#486

03-08-2015, 11:09 PM

Great post Peter, this is the reason why this forum was created. This large writes needs large replies, so here is my proposal:

1. Old days:
The debates about the correct way to measure tigers are well known by any of us, and like you described, the results were not satisfactory, as people keep using they own “methods” independently of the conclusions of experts like Sterndale (1884). One example is Dunbar Brander, which despite the fact of measuring his tigers “between pegs”, he made the great mistake of taking only the Total length, which from the point of view of Sterndale (and my own too) is a biased measurement that don’t represent the real size of an animal, especially on cats, specially by the great variation on the tail length in many specimens. Mazák (1981) stated that the tale of the tigers is slightly less than 1/3 of the total length, however we don’t know where he get this conclusion (probably Pocock (1929)), so we most believe this as a matter of “faith”.

There are few measurements of tigers, in the old days, that we can consider reliable and those that they are, lack of accuracy in some points, like Hewett and Brander which did not measured the tail of the animals (and other measurements) and produced incomplete results. In this case, I think that only the records of the Maharaha of Cooch Behar fill all the “scientific” parameters for a morphometric study. Sadly, even when in the 19 and 20 century, he was quoted as the best source for tiger size, by many hunters and Zoologist, his reputation fall in an abysm since Schaller (1967) stated that his records were biased toward the largest specimens. What a huge mistake!!! Schaller only take in count the last tables of the book, which in fact only mentioned the largest specimens, but he omitted all the other records inside the book, which reported the smaller ones and allowed to create the best comparison in the old literature. At this moment, only the study of Kerley et al. (2005), on the Amur tigers, can be compared with the great records of the Maharaja.

In regards of the old records, few of them are correct, there are others that are “over curves” but still reliable for comparison, but most of the records don’t even mention which method was used, which create more confusion. To that, we most add the fact that only “total length” was reported which add nothing to the idea of the real size of the beast. Sadly, people like Dr Karanth and Dr Yamaguchi just decided to close they eyes and label all the old records as “unreliable”, which is an incorrect decision.

2. Nepal tigers:
The “official” source on the size of the Nepalese tigers, from modern studies, is the document of Dr Sunquist of 1981, published by the Smithsonian institute, but sadly, the method of measurement is not stated. Now, we have this document which according with Waverider was a thesis from Tamang, where it mentions all the other measurements. I asked to Dr Sunquist where is this data published and he told me that he doesn’t know, but that the measurements were correct and that I could quote them.

Latter, in other conversations, already showed by me, Dr Sunquist stated that those tigers were measured in straight line, not over the curves, and this answer was stated to three different people, including me. @WaveRiders, in his hypocrite attitude decided to dismiss all the personal communications without any reason and in a coward move, he only said that he will not contact Dr Sunquist because he simply don’t want to. Dr Sunquist is a great person and NEVER left a question without an answer, Bold Champ and I literally “flooded” him with questions and he always answer it without any complain, even at this day! There is no reason to not ask him about this, so I think that Waveriders decision is more related with “pride” than with “science”.

I have no reason to doubt about Dr Melvin Sunquist and I believe in him, so I am sure that the animals were measured in straight line like he says. Interestingly, in the book “Big Game Shooting” of Phillipps-Wolley (1894) present a list of 4 tigers measured in Nepal “between pegs” and the largest was of 10 ft 2 inches (Sir. E. Durand, Bart.). Interestingly this is the same length reported by the Sauraha male (310 cm) and if we correct the length of the largest male hunted by the Maharaha of Nepal reported by E. A. Smythies (10 ft 9 inches over curves – 328 cm), we get about 311 – 314 cm, which is the same than the previous males. I think that about 310 cm is the record from Nepal (between pegs-straight line).

On the weight issue, there are many factors like the capture system (baiting) and the problem with the capacity (only with the largest males, of course). However, we have found that the food intake can be corrected and the final figure of the male Sauraha (261 kg) although a result of an equation, seems to fit in all our corrections made to the real last weight (bottomed a scale of 600 lb).

I think we are not going to found any 100% satisfactory answer in ANY field, as even people working in the same project will give you different points of view and approaches. Besides, this is not the first time that this happen: Remember the problem with the two large Amur tigers that presented different weights (Morden 1930 – 480 and 550 lb; Goodwin 1933 – 440 and 506 lb), the issue was finally resolved with a “personal communication” between Mazák and one of them (the same that I have do with Dr Sunquist). So, the point is why we most dismiss the personal communications, when they have been used previously to solve this type of problems?

3. Dr Karanth:
Like you described above, his is one of the greatest scientists and a real expert on tigers. However, in this particular issue (size), he seems confused but I think where the problem is.

Dr Karanth is one of those that think that all the “old” records are unreliable and that should be dismissed. In the same token, he probably don’t want to be confused with those methods and taking in count that the method used by the “hunters” in the Karnataka region was the one “between pegs”, he surely will dismiss them.

Now, is very easy to confuse the method “over curves” and “straight line”, after all, both methods use a tape stretched along the back and between the contours of the spine. The only difference is that while the “over curves” method follow all the curves, the straight line method stretch the tape and avoid those curves, sadly Karanth (2003) simply don’t clarify this issue. These few images show how tigers are measured by modern experts:

*This image is copyright of its original author

Not perfect but suggestive, and as we can see, they stretch the tape over the animal, in a straight form that avoids the natural curvatures of the body. I think Dr Karanth have done the same and if we take the words of Dr Sunquist, at least the two first animals captured in Nagarahole were surely measured in this way, as Dr Sunquist was present.

Sadly, in the case of the other two tigers, I can’t provide a clear conclusion, as at difference of Dr Sunquist, Dr Karanth don’t answer emails about the size of tigers. He have answer me everything about tiger ecology, prey specialization and methods of count tigers, but when I ask him about size, silence is the only result.

4. From Russia, with love:
I think that all of us are agree that the records from the Amur tiger are the only modern study of the morphology of the tiger and a real treasure for animal lovers. However, like you have say, there is the problem of the age of the specimens.

Kerley et al. (2005) states that an “adult” animal is the one able to reproduce, so in this way they classify all animals over 36 months old (3 years) as adults, and this is the same method that I have used in my tables. However, other studies on great cats used more accurate separations like those of Schaller and Smuts with the lions and Bailey with South African leopards, which separate them in more ages.

Like you say, the results present underestimations on size, but if we separate them in ages using the tables of Kerley et al. (2005) we can guess the differences. The problem is that the figures are “averages” of several measurements and only few of those are published as single figures. The example of the male “Dale” show us how many variations on weight can occur in the life of the tigers, but the logic will dictate that the tiger only grow, don’t shrink, with the age.

The mayor problem with the figures of the Amur tigers is not the size, but the weight. The fact of including sick and emaciated specimens was a real mistake as the resulted figure was of only 176 kg. However when I discarded those weights and including the new records from the southern area of the Russian Far East, the new average is of 190 kg and probably more now.

Surely, there is no doubt that the Amur tigers are the longest wild cats at this day, although the Bengal tigers are definitely the heaviest ones (more robust in the girth departments). Other thing, they are the only ones that clearly state the method of measurement (straight line with the tail apart), which add credibility and accuracy. If someone would do this with the records of Nepal and India, all confusions will probably end (or not?).

Conclusion:
Definitely, modern scientists are more concerned in saving tiger than measuring them, and that is the correct thing to do now. However, when those few animals that are captured for radiocollar studies are measured, they should use standard methods and report the results as the scientists currently do with the African lions and other great cats. Why Indian Scientists and Biologist don’t report they results? This always scape from my logic.

Other thing, the studies on skulls should use those housed in the native museums as they could house more impressive specimens. The large Nepalese skull reported by Dr McDougal is in Nepal and the large skull measured by Sterndale is in Calcutta India.

Shrink on modern tigers is also a real situation, and this is very clear in the Sundarbans and probably also in Malaysia (although in this last place, I am not quite sure). However, contrary to our previous believes, I think that Russian tigers have not changed its size as the modern and old records, on body size, match perfectly. The only thing that have changed is the weight and robustness, but with modern tigers reaching up to 212 kg in the new reserves, I think that we will start to read of large males in Russia very soon (I hope).

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