Size and weight siberian tiger

[GuateGojira]

(07-07-2023, 11:35 AM)AlejoBravo96 Wrote: Thank you very much Peter for replying. Just like Guajo, you have shown me a lot of information that I was unaware of and I thank you. To tell the truth, the reports that you show me are not as pessimistic as those that I have seen in other places. 
Now this question comes to my mind: I understand that the average weight for African lions is 180kg, that Atlas lions were actually not very different from African ones in terms of weight, which would leave the Bengal tiger as the Big cat capable of comparing itself to the Amur tiger as the largest? On the other hand, I found this publication given by the Federal State Budgetary Institution "Leopard Land" in which they assure that the most accurate historical average for the weight of the amurs is 220kg. In addition, Dr. Dina Matyukhina affirms that the specimens from this reserve do not have excessive fat, which is an argument that critics of Siberian tigers use to reduce the "effective" weight of the animal. So my question is, if you know the sources that institution used to establish that average? And if this publication can be taken into account in the analysis of averages that we have been talking about? Below I will leave the attached link and I also take the opportunity to ask you, please, one of your social networks to follow you. Again thank you very much.
Link: https://leopard-land.ru/about/news/959

Let me answer this one.

The lions had an average between 160 - 195 kg depending of the population, so an overall average of about 180 kg seems acceptable. Dr Yamaguchi estimated an average of 175 kg for males at species level. Barbary (Atlas or Berebere) lion was not larger than East African lions based on the evidence, in fact, as this was only a population of the current India/West African lions, is possible that they size was not greater than them. Bengal tigers are of the same size as Amur tigers, there is no evidence that suggest the contrary, both body length, shoulder height, skull size and body mass over time confirm it.

The website that you quote is not accurate when it says that the Amur tiger is the biggest of the cats, in fact, several scientists, including Russian ones, can tell you that. The website just quote the same mantra that many websites repite, with no real justification. The historical average of 220 kg that the website quote may have at least three sources:

1 - Sunquist & Sunquist (2002) published two average figures in the chapter about the tiger. The first one of 221 kg using " more recent measurements", but this is invalid as it use only 4 males from Heptner & Sludskii (1992) and one of them was a captive male estimated (not weighed) at between 250 - 260 kg, not unlikelly based in the huge size of the specimen, but not a real figure after all. The second average that they propuse is of 225 kg, again using specimens from Heptner & Sludskii (1992) althouh this time they use a sample of 9 specimens, some of them marked as "Reliable" by Slaght et al. (2005) but other not, including a figure of 325 kg that we will discuss latter. Interestingly in a second book from 2014 the same authors quote that "today tigers in the Russian Far East average about 500 pounds (225 kg)", which is contradictory as the same book says that "wild Amur tigers today are similar in size to Indian or Bengal tigers. We know this because the Siberian tiger project has been capturing, radio-collaring, and tracking tigers in the Amur region of the Russian Far East for fifteen years and has yet to document any wild tigers weighing more than the largest Bengal tiger." The Sunquist know that no Bengal tiger had an average of over 225 kg, so an average for modern Amur tigers is impossible, based in the fact that the heaviest male weighed (and reported/publihsed) at this moment is of 212 kg.

2 - Vratislav Mazák in his book "Der Tiger" of 1983 (I have the reprint of 2013) calculated an average of 233.4 kg based in 12 males, this is the second highest average calculated for any modern big cat on record (the first one is the figure of 235 kg for Nepalese tigers), it is impresive, but do have problems. Mazák included captive specimens and some of the animals in the list were clasified as "unreliable" by Slagth et al (2005), so the average figure is not reliable. What is insteresting is that the second heaviest male in the list (270 kg) is not show in the list of Slaght et al (2005) nor is found in any of the sources that I could check from old records, so there is a doubt if this was a wild male that we still don't know, or if this was a captive male recorded by him.


3 - Slagth et al (2005) is not a simple quote as you may think, this is the short quote from the chapter 6 of the monograph of the Siberian Tiger Project, the main author is Jonathan C. Slaght, Wildlife Biologist & Author, but the document also include the colaboration of other 10 tiger experts: Dale Miquelle, John Goodrich, Igor Nikolaev, Eugene Smirnov, Bart Schleyer, K. Traylor-Holzer, S. Christie, E. Arzhanova, Dave L. Smith and Ullas Karanth. This document analized, for the first time, all the weights published for Amur tigers in litterature, and although is possible that they could not found them all, they do reach a good sample and they analize they reliability. The result is that when we did check the source and reliability of the records, many of them are not based in real figures, or are just figures from news reports and impossible to confirm. So they classified the records in 4 categories, only the two first are reliable, while the other two are not and unconfirmed. The result of they analysis is that from 44 records only 9 were classified as "Reliable" while the other were not reliable, estimations or just impossible to confirm. The average calculated from the 9 males is of 215.3 kg, which is good and reflect the good size that the historic males had previous to the almoust extermination that they suffered at the middle of the 19 century. Of course the analysis is not out of questions, for example some specimens were classified as "unreliable" not because the source was bad, but because they were "evicerated" or because they could not found the original source, and that, from my point of view, is incorrect. The big male of 325 kg accepted by Dr Sunquist in his book of 2002 "Wild Cats of the World" was classified as unreliable because they could not found the original in Russian, and the English and French versions had discrepancies in the figure or simple do not had it.

So, these are the possible sources for the average of 220 kg that the webpage that you presented here is quoting. In my new document about the Amur tiger I included another male of 250 kg that was discarted as "unreliable" just because it was "evicerated" but that reached all the other requirements that made him a "средненадежный = Generaly reliable" record, so the new average figure for the historic males reliable recorded that I got was of 219.5 kg (n=11), which is very big by any standard. Reply