Who is the "king" of tigers? - Bengal or Amur

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Size of Chitwan tigers:

Through my investigation about the true about the tigers captured in Chitwan NP I manage to found a new document which brought light to one of the topics of big interest to all: body size.

Recently the last week I found this document:

“THE STATUS OF THE TIGER (PANTHERA, TIGRIS TIGRIS) AND ITS IMPACT ON PRINCIPAL PREY POPULATIONS IN THE ROYAL CHITAWAN NATIONAL PARK, NEPAL.”

The author of this thesis is no other than Dr Kirti Man Tamang and was published in 1982, one year after the monograph of Dr Sunquist. I am still reading it, so I don’t know if the information will update my conclusions, but for the moment it only confirmed it.

For example, it confirmed that the subadult male 104 was not captured as adult as they lost track of him after he dispersed. Also he includes information of tigress 109 which now I confirmed that was captured in 1977 and shows its body mass. But the most important thing is that I found that this is the document that presents the original measurements of the male tigers 102 and 105 PLUS the average measurements of the adult tigresses captured at that moment!!! Check this out:

 

*This image is copyright of its original author

Also, this table summarizes the information of all the animals captured by the project, including leopards, Sambars and even a sloth bear!

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

Incredible, don’t you think? Now about the method of measuring tigers, remember that Dr Sunquist already explained how it was:

 

*This image is copyright of its original author

So don’t start with that again, ok? Besides, there is more information about the body size of the deers captured in Chitwan NP, but I will post them in other topic, this is just for tigers.

What is important is that we can finally know the size of the tigresses captured. But you will say: Guate, but how can we know the head-body if there are just averages? You are right, there is only the average total length of the 6 adult females captured in that moment (267 cm) and the tail length (93 cm), but this give us an average head and body of 174 cm for the female tigers in Chitwan NP and that is important.

Now, I can dare to do something, and this will be my personal calculation based in the known facts. Knowing that the average tail represent 34.8% of the average total length, we can “speculate” that the same applies to the other specimens, so in this case I can do this to estimate the ranges:

F108 – Total length 251 cm * 34.8% = 87.4 cm = c.164 cm head body (the lower range).

F107 – Total length 282 cm * 34.8% = 98.1 cm = c.184 cm head body (the upper range).

In this form, we are able to reconstruct the maximum and minimum of head-body of the tigresses in Chitwan, however, how reliable will be that calculation? Well, we know that the tail of tigers is very variable and can be as much as 36% or as low as 30% (females in Cooch Behar and Sikhote-Alin). One tigress captured by Dr Karanth in Nagarahole NP had a relation of total length/tail of 35.1% (measured probably in the same way that the tigresses in Chitwan). The percentage of total length/tail for the tigresses in Cooch Behar and Sikhote Alin is 33.6% (n=17) and 34.5% (n=10) respectively, suggesting that, in average, the tigresses from Cooch Behar had shorter tails than those of Russia, if we assume that were measured with similar methods.

This means that the head-body length of the tigress 108 and 107 could be between 161-176 and 181-197 respectively. However remember that the tigresses in Cooch Behar were measured along the curves pressing the tape on the back and those from Russia were, apparently, measured in the same way, that is not the method used in Chitwan. So I will need a sample of tigresses measured between pegs or at least in straight line to get a better comparison.

Interesting is the fact that from 6 females the average chest girth was of 108 cm and the neck girth of 63 cm. This is bigger than that of the lionesses in Africa except those from Kalahari which had an average of 109.2 cm (Smuts et al., 1980). The average girth for tigresses in Cooch Behar is of 105 cm while that of those from Sikhote Alin is of 103 cm.  

Now, about the average weight, what figures used Dr Tamang to get the figure of 143 kg? Well in fact he used the highest figures of each tigress: 101-164, 103-129, 106-141, 107-154, 108-116 & 109-152 = c.143 kg mean.

Now we can add the weight of tigress F118 which weighed 159 kg, so the new average weight for adult females in Chitwan NP will be 145 kg (n=7) – range: 116 – 164 kg. Adjusting them with 14 kg of bait and/or pregnancy, the average will be as low as 131 kg, not different from my previous estimation.

This table summarizes the known sizes and weights of the adult tigers captured in Chitwan NP:

 

*This image is copyright of its original author

The length of M126 was taken from Dinerstein (2005) but I included only for reference as he don’t provide any exact number. I dare to make a calculation of the head-body length of the tigresses, and although I know that the variation is to large using just percentage values, I believe that at least the maximum and minimum that I included in the lower table (in italic and blue color) are close to the real figures, but as I said, those are my personal estimations, just that.

Now, here come all the images that summarize the information that we know about the size and weight of the Chitwan tigers at the moment, all data of Tamang (1982) is already showed above in this post:

Sunquist, 1981:

*This image is copyright of its original author

Dinerstein, 2003:

*This image is copyright of its original author

Dinerstein, 2005:

*This image is copyright of its original author

Mishra, 2010 - on Female 118:

*This image is copyright of its original author

Mishra, 2010 - on tiger "Banga Bhale":

*This image is copyright of its original author

Now, I cannot explain how important is for me to get these two documents:

* Smith, J. L. D. 1984. Dispersal, communication and conservation strategies for the tiger (Panthera tigris) in Royal Chitwan National Park, Nepal. Ph.D. thesis. University of Minnesota, St. Paul.

* Sunquist, M. E. 1979. The movements and activities of tigers (Panthera tigris tigris) in Royal Chitawan National Park, Nepal. Ph.D. Dissertation. University of Minnesota, Minneapolis, Minnesota. 170 pp.

Really, I tried to found it in the web and I am unable to reach them. Worldcat page says that are physical copies in some libraries in specific states in the US, so if someone can travel or live close to those places, please take a few pictures of it, try to search any information of body size and weights and, if possible, more information about the male tigers, specifically M105, M126 and any other male.

Thank for your attention, greetings to all.

Ps. I made more modifications in my post 430. Check the new table and some minor changes in the text. Reply