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

peter Offline
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( This post was last modified: 04-06-2020, 07:37 AM by peter )

(04-04-2020, 10:40 AM)GuateGojira Wrote:
(04-02-2020, 10:36 AM)strana Wrote: Guate,
First, thanks for another very interesting material.
However, I think that the size of modern Amur tigers are underestimated. There are some pics of very impressive wild tigers in Russia here in Wildfact; I would not be surprised if some of them reach 250 kg+. I believe only the young/not very healthy are weighted. Wild Bengals and Amur might have similar size, but ok, it is just speculation.

Hello, thank you for your words.

About the size of the Amur tiger, in fact the data on the image takes in count both historic and modern weights. Surely there are photos of very impressive male in the Russian Far East, but sadly none of them has been weighed, so for the moment the biggest male recorded between 1992 to 2012 (the last year when weights were published) was of 212 kg.

Now  about the sample, it is not true that only young or not-healty males were weighed, let me explain to you first. In 2005 Dr Slaght and other scientists published a chapter in the monograph of the Amur tiger published by the Siberian Tiger Project (in Russian only), especifically the chapter No. 6. Now, in that document they calculated an average weight of 176.4 kg (n=18; range: 125 - 205 kg) for males and 117.9 kg (n=13; range: 113 - 129 kg) for females. However those figures includes specimens that were not in good shape, in fact the weight of 125 kg was for male in such a bad shape that was eutanized! Also, the sample includes specimens over 3 years old, as for scientists an animal is "adult" when they are sexually mature. Now, in order to get a more reliable average figure I investigated all the reports about the Siberian Tiger Project, plus the new males/females captured by the Amur Tiger Programme and I excluded the specimens in bad shape, although it was not posible to exclude the specimens between 3-4 years old for obvious reasons. At the end, my result was of an average weight of 190 kg (n=23; range: 155 - 212 kg) for males and 121 kg (n=15; range: 110 - 136 kg) for females, taking in count only the specimens captured between 1992 and 2012. For the moment those are the most reliable figures about the body mass of the Amur tigers, but take in count that after the year 2000 more males of 200 kg or over had been captured, so I think that there is a big posibility that males over 215 kg are now there in the Russian Far East.

If we use the weights of the Amur tigers in the past, we can see that they were of about the same size of the Bengal tigers, with confirmed weights of about 250 kg and the skulls shows that they could be slightly longer too.

THE RELATION BETWEEN HEEL WIDTH AND WEIGHT IN WILD AMUR TIGERS - I

Decent explanation on the problems distinguishing young adults (3-4 years of age) from adults (5 year and over), Guate. Most reports on young adult males I have suggest they range between 150-180 kg. If a table has young adults, chances are the average will be affected. 

a - Heel width range in wild male Amur tigers 

As to the weight of wild Amur tigers captured or photographed after 2005. In brown bears, heel width is a good indicator of weight. My guess is it isn't much different in big cats. In most male Amur tigers, the heel width ranges between 10,0-12,5 cm. Male tigers with that width, depending on age, range between 100-200 kg. 

b - Heel width in large male Amur tigers

As far as I know, there're three reports about male Amur tigers with a heel width ranging between 13,0-14,0 cm. One of them is mentioned in 'Winter ecology of the Amur tiger' (A.G. Yudakov and I.G. Nikolaev, 2nd revised edition, Vladivostok, 2012, pp. 144). The two other reports are recent. The male below has a heel width of 13,5 cm. The photograph was first posted by Lycaon: 


*This image is copyright of its original author


c - The effect of growth on the relation between heel width and weight in wild Amur tigers

There's, as I said before, no reliable table with information on the relation between heel width and weight in wild Amur tigers. I did, however, find this table. Although the scope is limited (it has information on 2 young adult males and two adult males only), it's something. The table also has information on the effect of growth in wild Amur tigers. It strongly suggests wild male Amur tigers continue to grow until they're 7-8 years of age: 


*This image is copyright of its original author


d - The relation between chest girth and weight in brown bears

Below is a link to an interesting article on the relation between chest girth and weight (and zygomatic width and weight) in brown bears: 

https://www.bearbiology.org/wp-content/uploads/2017/10/Glenn_Vol_4.pdf

I will add a bit more on brown bears in the next posts.
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Messages In This Thread
Demythologizing T16 - tigerluver - 04-12-2020, 11:44 AM
Tiger Data Bank - Apollo - 07-28-2014, 09:54 PM
RE: Tiger Data Bank - Apollo - 07-28-2014, 10:02 PM
RE: Tiger Data Bank - Apollo - 07-29-2014, 12:56 AM
RE: Tiger Data Bank - peter - 07-29-2014, 07:05 AM
Tiger recycling bin - Roflcopters - 09-04-2014, 01:36 AM
RE: Tiger recycling bin - Pckts - 09-04-2014, 02:22 AM
RE: Tiger recycling bin - Roflcopters - 09-05-2014, 01:01 AM
RE: Tiger Data Bank - Apollo - 11-15-2014, 10:07 PM
RE: Tiger Data Bank - Apollo - 11-15-2014, 10:57 PM
RE: Tiger Data Bank - Apollo - 11-15-2014, 11:33 PM
RE: Tiger Data Bank - Apollo - 02-19-2015, 11:25 PM
RE: Tiger Data Bank - GuateGojira - 02-23-2015, 11:36 AM
Status of tigers in India - Shardul - 12-20-2015, 03:23 PM
RE: Tiger Directory - Diamir2 - 10-03-2016, 04:27 AM
RE: Tiger Directory - peter - 10-03-2016, 06:22 AM
Genetics of all tiger subspecies - parvez - 07-15-2017, 01:08 PM
RE: Tiger Predation - peter - 11-11-2017, 08:08 AM
RE: Man-eaters - Wolverine - 12-03-2017, 11:30 AM
RE: Man-eaters - peter - 12-04-2017, 09:44 AM
RE: Tigers of Central India - Wolverine - 04-13-2018, 01:17 AM
RE: Tigers of Central India - qstxyz - 04-13-2018, 08:34 PM
RE: Size comparisons - peter - 07-16-2019, 05:28 AM
RE: Who is the "king" of tigers? - Bengal or Amur - peter - 04-05-2020, 05:49 AM
RE: Amur Tigers - peter - 05-20-2021, 07:13 AM
RE: Amur Tigers - Nyers - 05-21-2021, 08:02 PM
RE: Amur Tigers - peter - 05-22-2021, 08:09 AM
RE: Amur Tigers - GuateGojira - 04-06-2022, 12:59 AM
RE: Amur Tigers - tigerluver - 04-06-2022, 01:08 AM
RE: Amur Tigers - tigerluver - 04-06-2022, 09:08 AM
RE: Amur Tigers - tigerluver - 04-06-2022, 11:30 PM
RE: Amur Tigers - peter - 04-08-2022, 07:27 AM



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