Modern weights and measurements on wild tigers

[BorneanTiger]

(10-18-2019, 04:32 AM)GuateGojira Wrote:

(10-15-2019, 02:15 AM)GuateGojira Wrote: With the Bengal tigers, in old records, we have many weights to compare the tiger populations, but from modern records we have very few.  Using all the available figures, hunting and modern, I calculated an average weight of the Bengal tigers from India and Nepal at 211 kg (465 lb) - n=141; including Sundarbans it will be 200 kg (440 lb) - n=147. In the mainland all the populations are over  200 kg on average, except from the one of southeast India which  is about 182 kg, but from here we only have hunting records. I found that there is no significant diference in body length between the populations, just in weight which range between 182 to 243 kg.

I had a full list of at least 160 male specimens from hunting and modern records, but sadly I lost all that information, so I manage to recover this list of 147 specimens in order to get a good idea of the average weight of male Bengal tigers in the Indian Subcontinent:

Central India: 204 kg - n=55 - range: 160 - 255 kg.
Southwest India: 218 kg - n=6 - range: 206 - 227 kg
Southeast India: 182 kg - n=9 - range: 150 - 203 kg.
Northwest India: 243 kg - n=3 - range: 220 - 268 kg.
Northeast India: 205 kg - n=44 - range: 168 - 236 kg.
Terai-North India: 200 kg - n=17 - range: 161 - 259 kg.

Nepal: 224 kg - n=7 - range: 180 - 272 kg+.
Sundarbans: 123 kg - n=6 - range: 97 - 172 kg. 

I still need to recover lees than 10 weights that I had, but the difference in the average figures will be minimal, I still remember that the average in the Southwest will be smaller and that in Northeast India will be higher. This list excludes all the specimens over 272 kg, including them in a group of "exceptional specimens" that range from 276 kg (Kumaon) to 320 kg (Nepal), and is a list of 6 males, please take in count that these records are tied to its acceptance and not all are accepted as "reliable", however at liest in the case of a huge male of 282 kg in Kumaon it clearly says that was actually weighed. This sample includes only the 16 males recorded by scientists and published or corroborated by email. If we include all the other weights reported by news webpages in this topic the sample will be higher but I don't think that the average will be dramatically different.

Update of the information about the weight of Bengal tigers:

I manage to found the other specimens that I lost, and I hope that I found them all. If I still missed a record, feel free to post it here.

I found 22 new figures for males and 10 for females and added them to the main figures in they respectivelly areas. Just 4 weights, 2 males of 355 lb and 470 lb, and two females of 235 lb and 309 lb, were not added to the main average because they did not say the specific area were they came from. So I used the other 167 male specimens and 102 female specimens to get the following average figures:

Males:
Central India: 201 kg - n=61 - range: 160 - 255 kg.
Southwest India: 196 kg - n=12 - range: 159 - 227 kg
Southeast India: 182 kg - n=9 - range: 150 - 203 kg.
Northwest India: 243 kg - n=3 - range: 220 - 268 kg.
Northeast India: 207 kg - n=51 - range: 150 - 256 kg.
Terai-North India: 200 kg - n=17 - range: 161 - 259 kg.
Nepal: 224 kg - n=7 - range: 180 - 272 kg+.
Sundarbans: 123 kg - n=6 - range: 97 - 172 kg.
** Average, mainland only: 208 kg - n=160 - range: 150 - 272 kg.
     Av. including Sundarbans: 197 kg - n=166 - range: 97 - 272 kg.

Females:
Central India: 133 kg - n=52 - range: 105 - 157 kg.
Southwest India: 145 kg - n=2 - range: 113 - 177 kg
Southeast India: 122.5 kg - n=11 - range: 109 - 150 kg.
Northwest India: 149 kg - n=3 - range: 135 - 170 kg.
Northeast India: 135 kg - n=13 - range: 99 - 163 kg.
Terai-North India: 136 kg - n=6 - range: 118 - 148 kg.
Nepal: 143 kg - n=9 - range: 113 - 164 kg.
Sundarbans: 82 kg - n=6 - range: 72 - 109 kg.
** Average, mainland only: 138 kg - n=96 - range: 105 - 177 kg.
     Av. including Sundarbans: 131 kg - n=102 - range: 72 - 177 kg.


As I believed, some average figures changed, specifically those from Central, Southwest and Northeast India. These figures include the specimens from the Naga hills, Assam region, and also the very small males of the  Mahratta region in southwest India. So I tried to include all the weights available, but I excluded the record weights of over 272 kg as they are clasiffied as "exceptional".

I still believe that the inclusion of the Sundarbans tigers is incorrect, as they are clasified as a completelly diferent Ecological Conservation Unit, which elevate them at the same category as the Thailand, Malayan or even Amur tigers. However, to please all the public, I put all the posible situations in the figures. Also, remember that I am 100% sure that many of those small records of males of less 180 kg are probably subadults, old specimens or ill and in bad shape. Some of them were found even with porcupine kills on them! However, I did included them just to show an unbiased sample. Latter, maybe I will present a sample remouving the "problematic" specimens or those that obviouls are not fully mature.

Greetings.

I wouldn't treat the Sundarban tiger as a completely different ECU to all other Bengal tigers if I were you, because as I mentioned in the main thread, while talking about whether or not the Amur tiger of Northeast Asia should be treated as the same subspecies as the Caspian tigers of Central and Southwestern Asia, just as these tigers are closely related, the Sundarban tiger is closely related to tigers in Central and Southern India, though significantly genetically different from those in the Himalayan region where north India meets Nepal and Bhutan.

Luo et al.: https://journals.plos.org/plosone/articl...ne.0004125 
   
Figure 2. Phylogenetic relationships among tiger mtDNA haplotypes inferred using 4079 bp of concatenated mtDNA sequences (see Table S3).

Singh et al.: https://www.ncbi.nlm.nih.gov/pmc/article...8846.g002/ 
   
Median-joining network created from four mtDNA genes (cytb, ND2, ND5 and ND6) (in total, 2600 bp) depicting genetic relationship between all haplotypes found in tigers.

(a) haplotypes found in Sundarbans tigers (in black) and all other six tiger subspecies (in yellow and green color, from Luo et al. 2004) [2], (b) all haplotypes found in Bengal tiger populations from this study and Mondol et al. [22]. Pink: North India, Yellow: Central India, Blue: South India, and Green: Sundarbans. The sizes of the circles are proportional to the haplotype frequencies.

Sundarban Bengal tiger: https://commons.wikimedia.org/wiki/File:..._Tiger.jpg 

*This image is copyright of its original author

Central Indian tiger (Munna?) at Kanha National Park: https://commons.wikimedia.org/wiki/File:...ted_01.jpg

*This image is copyright of its original author

Southern Indian tiger at Periyar tiger Reserve: https://timesofindia.indiatimes.com/city...362331.cms

*This image is copyright of its original author

Northern Bengal tiger at Jim Corbett National Park, northern India: https://www.dhikalaforestlodge.in/cobett...-park.html 

*This image is copyright of its original author

Reply