|
In what groups we can divide the Bengal Tiger?
|
Hi to all, members and reader.
My question is: In what groups we can divide the Bengal Tigers (Panthera tigris tigris) based on the different regions, and based on the morphological differences? For example, it's clear that the tigers from the Terai Arc are different from the tigers from Sundarbans. We thought to reorder some sections, for avoid the fragmentation of information. I would ask if you have any suggestions; all information is good. @peter @Roflcopters @Apollo @Pckts @Shardul  (03-21-2017, 11:07 PM)Ngala Wrote: Hi to all, members and reader. I like the Terai Arc or Northern Indian Tigers Then Central Indian Tigers Then Southern Indian Tigers Then Amur, Sumatran, Sunderbans and any other sub species. Would be my vote, I think its nice to view tigers by region over specific parks. It's a little confusing with kaziranga tigers and Ranthambhore, but you could probably include both in Northern Indian Tigers.
Thanks Pckts for your reply. It's possible this subdivision?
- Terai Arc (Northern India like Corbett, Nepal, Buthan) - Central India (Kahna, Pench, Tadoba, Nagzira, Bandhavgarh, Ranthambore, ...) - Southern India (Eastern and Western Ghats; Wayanad, Bandipur, Nagarhole, ...) - Assam tigers (Kaziranga, Manas, Orang, ...) - Sundarbans
I'm not sure, but i think that is too distant from Terai Arc for be considered part of it.
I would say,
Northern Northeastern Northwestern Central Southern Sunderbans All these populations are genetically isolated from each other. 
I am not expert, but I think this should be the categorization
- Terai Arc (Northern India like Corbett, Nepal, Buthan, Assam tigers) - Central India (Kahna, Pench, Tadoba, Nagzira, Bandhavgarh, ...) - Southern India (Eastern and Western Ghats; Wayanad, Bandipur, Nagarhole, ...) - Assam tigers (Kaziranga, Manas, Orang, ...) - Sundarbans - North West (Ranthambore, Sariska) Actually, I think if some one can make profile picture of tigers from these region with facial mark, side profile etc.. so that one can recognize tiger from a particular area very easily  (03-22-2017, 09:33 PM)sanjay Wrote: I am not expert, but I think this should be the categorization Northwest, Central & Southern are not differentiated by National Tiger Conservation Authority...There is ample genetic intermixing along the contacts points (like north of Western-Ghats & south of Eastern-Ghats...& Kuno-Madhav tract also joins Vindhya to West-India-Landscape, in theory) they got "seperated" less than 50yrs ago... Sundarban tigers show unique local adaptation...but turned out to be not-that-different genetically. The far Northeast was confirmed to have certain degree of Indo-Chinese ancestry!!! That's it... 
PANTHERA TIGRIS TIGRIS - REGIONAL DIFFERENCES
a - Two subspecies only Before we start on the differences between tigers living in different regions in India, we have to remember that biologists today distinguish between Mainland tigers and Sunda tigers only. The proposal developed by Pocock in 1929 (8 tiger subspecies), therefore, is out. This to prevent misunderstandings. b - Regional differences in India I've been collecting information on morphology for quite some time now. At the moment, I'm developing a system to get the data to the right place. The question is if there is something like 'a right place' (regions) in India. In order to get to an answer, I went over everything I have. I got to 13 regions. c - Regions 01 - Nepal and northern India. 02 - Bhutan. 03 - Northeastern India (alluvial plains). 04 - The southeastern part of Assam. 05 - Bengal. 06 - Sunderbans. 07 - Ranthambore. 08 - Northcentral India. 09 - Southcentral India. 10 - Eastern central India. 11 - Deccan. 12 - Southwestern India. 13 - Southeastern India (north and west of Madras). d - Additional remarks Ad 01 - Most tigers in this region live in wetlands or plains (Nepal in particular), but others do not. Both types seem to be somewhat different. Ad 02 - Referring to the elevated parts of Bhutan. Ad 03 - Most tigers in this region live in alluvial flood plains, but others inhabit elevated parts of the region. Ad 04 - Tigers living in this part of Assam could belong to Panthera tigris corbetti. They are definitely different from those in the north. Ad 05 - Bengal tigers are more or less gone, but there is a lot of information in old books. Ad 06 - Sunderban tigers are very similar to tigers living in central parts of India, but smaller. Ad 07 - Ranthambore tigers seem different from those in northern and central India. Ad 08 - There are distinct geographical differences between northern, southern and eastern parts of central India. Ad 09 - See 08. Ad 10 - See 08. Ad 11 - The Deccan is a plateau. Tigers seem a bit smaller than those in central and western parts. Ad 12 - The Western Ghats can be divided into several distinct parts. Some of these produced large tigers. Others did not. Ad 13 - Although tigers are largely gone in this region, they were described in old books written by hunters. e - To finish the post - The distinction above is largely based on length and weight. There are more criteria. Anyone with good info is invited to post it in this thread. - We could limit the number of regions. Anyone able to help out is invited to do so. - I was thinking of adding a good map of India, but couldn't find one. We need one with altitude, forest cover and human settlements. 
I far from an expert on this regarding tigers, but I have had the same thoughts and questions about lions after watching them for several years and seeing how different they are from region to region, going from Krüger to west and eastern populations all are different some much more so than others.
Here's my personal view on the Tigers: Terrai seems to me very much like the Assam tigers probably because they share very similar habits living in marsh/wetlands lands with high grass or dense forests they seem to have a huge upper body unlike any cat's today, also are they probably of the slowest cats because of their massive weight, but that's because they don't need to be fast. Because with such great cover they can grab prey by pouncing on them from extreamly short distance, and that they are surrounded by large prey that they can and have adapted to prey on, and the terrain makes that way easier for an probably less agile version of the Bengal tiger. The Ranthambore Tigers are a tough one, where do we put them? It's a unique version imo. Very big although not as massive muscles in their front quarters as others, but they are very long, tall and overall extreamly solid. And they don't hunt bovines so they, are hunting mostly fast prey like deer (sambar and Axis) and Nilgai, so they are probably the fastest of the tigers. Central tigers are the most overall solid tigers imo, they have massive heads with big necks, are long and tall, and are overall very muscular tigers, with some being larger than others, with Kanha and Pench probably having the biggest ones in Central India, some big individuals in Tadoba and Bandhavgarh etc, but on average they seem a little bigger, they have lighter orange fur. And are adapted to hunt fast both small to large prey from langur and axis up to gaur in size and need to be both fast, agile and strong. South Indian tigers: much of the same as with the central Indan tigers, small to large prey and needs to be very fast, agile and strong as they tackle much of the same prey, and I disagree with the popular saying they they are smaller, there are several individuals from especially Bandipur that are huge, but probably smaller on average.. But they have smaller heads. (03-23-2017, 01:04 AM)peter Wrote: PANTHERA TIGRIS TIGRIS - REGIONAL DIFFERENCES Ok.. im sorry..but these are somewhat incorrect... Visit here for forest & landuse cover..(ISRO's satellite remotesensing data, keep changing the name of the state & use that "landuse&landcover" button) http://bhuvan.nrsc.gov.in/state/WB & here..(download) https://www.google.co.in/url?sa=t&source...ANE5Lb54EA & here...(download) https://www.google.co.in/url?sa=t&source...owfDOI1sDg 1 & 2 are more or less legit.. Bengal consists of north Bengal (part of northeast landscape, tiger come from 2 Bhutan), Sundarbans & parts of Chhotanagpur plateau (which in turn is a part of deccan) to the west, no more tigers there for a while. 3&4 both should show Corbetti genes, more in East less in west..Detailed studies didn't take place, cant say..But they do, that was confirmed (Quote me for link) 7 is a part of Western india tiger landscape...(See latest posts in Bigcat news)..which is the Malwa plateau, that in turn is a part of Deccan.. Tigers there look similar to each other (large but lean & that typical not-so-impressive neck) because the population was choked by POACHING to 10-15 individuals...Twice, in early '80s & late '90s. Now they are 60 & populating Sariska & Kuno...But the whole genepool was sourced from less than a dozen animals. So, there's a lotta genetic overlap...(The parents of almost ALL Ranth tigers alive today, had Macchli ancestry, some from both parents's side, themselves! Most even look like her, EVERYONE of them are first,second or third cousins.  )Notice how those days BambooRam, Nick, Xmale looked distinct..but Today t24 t34 t42 t28...etc.etc. All looks very similar of face & physique!!!.. 8,9,10,11,13 are part of same landscape called Eastrn Ghat & Deccan Plateau (Read NTCA Booklets from link provided above) & Google "Deccan". There is very little difference in physical features & vegetation sfifts from evergreen to deciduous to dry-throny Northwest wards. 12 Consists of Western Ghats & Nilgiri Biosphere reserve... To finish the post.......... There are absolutely no notable physical differences, other than that the tigers of the south WERE found to be slightly lighter & leaner (NOT smaller) on average. Read NTCA book for data on genetic intermixing!!! Even Sundarban tigers were confirmed to be genetically similar to Central Indian tigers, just some local adaptations (quote me for link)...Same might be the case for Bhutan tigers (no largescale studies done).
I think that these are nice maps about the elevation and forests cover in India. @peter
In the link there are the maps on the temperature and rainfall. Source: Nationwide classification of forest types of India using remote sensing and GIS Sudhakar Reddy, Jha, Diwakar & Dadhwal, 2015 Fig. 3. Elevation zone map of India  *This image is copyright of its original author Fig. 6. Distribution of level 1 forest types across biogeographic zones of India  *This image is copyright of its original author Fig. 7. Vegetation type and land use/land cover map of India  *This image is copyright of its original author Fig. 9. Vegetation type and land use/land cover map of India translated as per Global Land Cover 2000 (FAO LCCS) legend  *This image is copyright of its original author
This is a good question, one that deserves an answer.
From my point of view, there are different approaches in this subject, like the morphological, the habitat differences and the human intervention. 1. Morphology: From a morphological point of view, I have saw so many measurements and types of coats to say that I don't see too much differences between the populations. Fore example, I have saw Ranthambore tigers with coats that can be confused with Amur tigers and the same phenomenon is seen in the winter at Nepal and Buthan. South India tigers do not have this variations, but still they behavior is the same, and there is no difference between them and the summer coats of the northern tigers. Popularly is stated that Northern tigers are the biggest and Southern ones are the smallest, but this is not accurate at all. In fact, the skulls that are normally quoted are scanty and sample sizes are even lower than those of weights and lengths, so to create a conclusion based in two or three skulls, like Pocock (1939) done, is dangerous. In body terms, Tigers from the Terai arc, Assam, Central and southern India are of the same size, which is between 260 - 310 cm in total length and all these populations reach the weights of 160 - 260 kg, the same case apply with the females with similar ranges. The exception is with the south east of India, with those of Hylderabad, but the terrain is somewhat different there and probably affected them size development (weights of no more than 203 kg are reported). The Sundarbans tigers are the exception of all, with sizes and weights in the range of the Sunda tigers, however this change is very early and caused by human intervention. Old records from this area shows less than 5 specimens, but all of them fit in the range of the other mainland tigers. The shrinkage of this population is a reflect of the changes made by the humans in its habitat. 2. Habitat: The Indian subcontinent is a magnificent mosaic of climates, terrains and prey diversity, tigers evolved its best form in this continental treasure. Despite the differences in climates, again it seems that the differences between the main populations of the Terai arc, Central and South west India are about the same, taking in count also the differences in prey densities and varieties. Sundarbans is again the black dot in the white page, been the only tiger population that lives in mangroves and with such a low prey density. 3. Human intervention: I think that this is the main reason of the modern "differentiation" of the populations in the Indian Subcontinent. In the old days, the tiger populations were contiguous and were not natural barriers. After the growth of the human population, the tiger groups were slowly fragmented and diminished at his modern numbers. The most affected is the one of Sundarbans, which are genetically related with Central Indian tigers, but with the habitat type, its isolation and the very small size of the prey, changed into a very small form. I remember one shocking thing about the origin of the Ranthambore tigers, which according with Valmik Thapar, are the result of a group of reintroduced specimens that came from the region of Gwalior. I am going to search the page and the book were he said this. This means that some "populations" are already intermixed since many years. Well, this is a very quick analysis, but with more information I can go deeper. For the moment, my "classic" differentiation of the Bengal tigers has been: 1. Northwest population (West Terai arc region). 2. Nepal (Central Teria region). 3. Northeast population (East Terai arc region). 4. Central India. 5. Southwest India (Western Ghats region). 6. Southeast India (Hyderabad region). 7. Sundarbans. However, with more information and data, my classification is going to change and it will to be reflected in the new tables. These are my two cents. Greetings to all.
(04-27-2017, 06:02 AM)GuateGojira Wrote: The Sundarbans tigers are the exception of all, with sizes and weights in the range of the Sunda tigers, however this change is very early and caused by human intervention. Old records from this area shows less than 5 specimens, but all of them fit in the range of the other mainland tigers. The shrinkage of this population is a reflect of the changes made by the humans in its habitat.Do you have them...Plz, share if yuo do!!!
Yes, I think I have the 5 specimens.
Actually we need to thank @peter to that, as he found it first. I am going to search them for you. For the moment, I can tell you that the only two weights for these old specimens were a male of 172 kg and a female of 109 kg, very low but still in the mainland tiger range. The total length was of 283 cm (tail of 95 cm) for the male and 250 cm (tail of 89 cm) for the female, I think between pegs. I am quoting from memory, just saying. 
|
| Users browsing this thread: |
| 1 Guest(s) |