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

[peter]

ON THE SIZE OF CAPTIVE AMUR TIGERS - I 

I.1 - Introduction

About a year and a half ago, using articles and books published in 1974, 1993, 1996, 2003, 2005, 2011 and 2019, I did a series on the size of wild Amur tigers and Ussuri brown bears. 

In post 2,466, the relation between heel width and weight in both tigers and brown bears was discussed. Post 2,469 has information about the relation between heel width and weight in tigers. Post 2,472 has information about the vital statistics of male tiger 'Banzai', whereas the table published in 2005 (about the length and weight of 11 male Amur tigers) was discussed in post 2,475. Post 2,491 has more information about the relation between heel width and weight and tigers and post 2,511 has information about the total length and weight of male Amur tigers and male and female brown bears. 

The conclusion (see post 2,511) was adult (4 years and older) male Amur tigers averaged 184-185 kg and 298-299 cm in total length (measured 'over curves'), whereas adult (8 years and older) male brown bears, although about 15-20 cm shorter in head and body length (measured in a straight line), averaged 257,5 kg. Compared to adult male tigers, male Ussuri bears were shorter, taller and significantly heavier. 

The problem is the lack of recent, reliable, information about the size of adult wild male Amur tigers. This is the main reason I decided to discuss the relation between heel width and weight in most of the posts mentioned above. If you conclude it was an indirect way to find out a bit more about the size of wild Amur tigers today, you would be close. 

There is another, indirect, way to find more information about the size of wild Amur tigers. I'm referring to the weight and dimensions of their captive relatives. The condition is good data. The problem, as you guessed, is there's not too much known about the size of captive Amur tigers. Those interested in big cats often say captive Amur tigers are the largest big cats, but I never saw a table based on reliable information.

In order to get to an answer, I decided to do it myself. I started about half a year ago. A week ago, I concluded I had enough to get to a few tables. With 'enough', I mean I found decent (read quite reliable) information about the weights of 27 Amur tigresses and 61 male Amur tigers. Not bad, but I was hoping for a bit more. Information about the size of captive Amur tigresses in particular is few and far between.  

Information about the actual standing height at the shoulder, however, was even more difficult to find. Same for skull measurements and total length (measured 'between pegs'). 

I.2 - Sources

How reliable are the tables that will be posted? This question, unfortunately, is difficult to answer. I do not doubt the information found in scientific publications, but I'm not too sure about the information found in newspaper articles. For this reason, I tried to find as much as possible about individuals mentioned in these articles. In the 'List of references', you'll notice the space between different sources. When there's no space between two sources, it means they belong together (meaning both have information about the same tiger or tigress). 

Apart from scientific publications and newspaper reports, I used a few videos and information found in a few threads of our forum. I'm referring to the threads 'Captive lion and tiger weights' and 'On the edge of extinction - A - The tiger (Panthera tigris)'. Every post that has information about the size of captive Amur tigers was checked and again. All posts used for the table were considered reliable. With 'reliable', I mean as reliable as it gets. For a forum, that is.       

The most informative and reliable source still is 'Der Tiger'. This great book (referring to the third edition published in 1983) written by V. Mazak is one of the very few that has good information about the size (referring to total length measured 'between pegs', standing height at the shoulder and skull measurements) of captive Amur tigers. V. Mazak also wrote 'Notes on Siberian long-haired tiger, Panthera tigris altaica (Temminck, 1844), with a remark on Temminck's mammal volume of the 'Fauna Japonica' (in: Mammalia, 31 (4), pp. 537-573, 1967). This publication has reliable information about the skull size of wild Amur tigers.

In the period 2005-2021, however, interesting studies about the size of Amur tigers living in Chinese facilities and safari parks have been published. I'm referring to 'Study on growth and development of Amur tigers raising dispersedly', Weilin (S), Dissertation for the degree of Master, Northeast Forestry University, 2005 and 'Body measurement parameters and body weight of sub-adult and adult Amur tigers (Panthera tigris altaica)', Cui (Y) et al., Chinese Journal of Wildlife 2021, 42 (4), pp. 965-972 in particular, but there are more publications that are of interest.    

The tables (referring to the tables I'll post in a few days) also have information about a few Amur tigers in Japanese zoos. The reason is our member 'Betty' found and sent me the publications needed. Same for the Chinese publications I referred to in the previous paragraph and all reports published in Japanese and Chinese newspapers (referring to information used for the table). I also got an interesting article 'Betty' found on a (Korean) blog about a quite famous tiger living in the Seoul Zoo in the sixties of the previous century. I'll post the article after I posted the tables. 

If I was to conclude I would still have been struggling without the help of 'Betty', I would be very close. Many thanks, Betty!  

I.3 - Posting sequence

I'll start the series with the Chinese publications discussed in I.2. The reason is you won't find both studies in the list of references. A bit strange perhaps, but I didn't use the studies for the tables. The reason is they don't have nformation about individual tigers. Before posting scans of the tables in both studies, I'll add a number of remarks. All of them are based on information I got from 'Betty'. 

I'll also discuss a table about the size of captive Amur tigers posted by our member 'Kingtheropod' some years ago. I used some of the sources he found as well.

After posting both tables, I'll post the list of references, additional remarks and a few conclusions. 

In between, I assume our member 'Khan85' will post recent information about the size of wild Amur tigers he got from a researcher working in Russia. This information can be compared with information published in 2005 ('Tiger in Sichote-Alin Zapovednik: Ecology and conservation', Miquelle et al., 2005, in Russian) and discussed more than once in this thread (referring to the table that included 4 young adult males).

I.4 - A series about the size of captive Amur tigers in a thread dedicated to wild Amur tigers?

Yes. The first reason was explained in I.1. The second is there could be a relationship between the size of captive Amur tigers and their wild relatives. Using information about the size of captive Amur tigers, we could get to a hypothesis about the size of their wild relatives. 

This assumption is based on reliable information about the size of captive and wild Indian tigers (Panthera tigris tigris) in particular. Adult male Indian tigers (referring to 3 decent samples) in captivity average 185-190 kg (409-420 pounds), whereas as their wild relatives seem to be significantly heavier (210-215 kg or 464-475 pounds). In some regions, adult males (referring to averages only) could exceed that mark.  

The reason wild tigers often are heavier than their captive relatives is tigers are big game specialists. All adult males are individuals that survived the challenges they met in the period in which they became independent and established a territory. In that period of time (between 2-5 years of age roughly), they also survived encounters with competitors and, in particular, the animals they hunt. This means they are true (able) survivors. This is not true for their captive relatives. Those who had the opportunity to observe wild and captive tigers agreed captive tigers are mere shadows of their wild relatives. 

Although it hasn't been confirmed in studies, hunters in British India agreed male tigers in particular continued to develop after reaching adulthood. The largest individuals shot in the period 1860-1960 often exceeded 10 years of age. This development seems to be less pronounced in captive tigers. Captive male Amur tigers (referring to the Chinese studies mentioned in I.2) often quickly lose size (referring to total length and weight in particular) after reaching 7-8 years of age. Captive Amur tigers (males and females) also have significantly narrower 'heels' (referring to the heel width of the front paws). Reply