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

[GuateGojira]

I am definitely in the same idea of Dr Sunquist:  I biased toward tigers!!!!

I love when new conversations about tigers arises and these new comments on the South China tigers lured me here again.

As you know, I stop making comparative images of animals for time issues, but I still have not finished the tigers, I missed the Indochinese (and Malayan also included) and the South China tigers. In this case, my information on Indochinese tigers is very limited, so @peter I will like, if you can, to see all your data on this subspecies again, I only trust in your data which I remember, was the best in this subspecies. It is interesting to mention that the "modern" size and reports of the Malayan tigers is not representative of the past. Old records show animals of the same size than Indochinese specimens and Kitchener & Yamaguchi (2010) showed that the largest skull reported by Mazák for the Indochinese tiger (365 mm) was in fact from a Malayan tiger! That is why I decided to mix them both, for obvious reasons.

On the South China tigers, I have also very few measurements, all between pegs, some skulls and a few weights. What I have found with this few data is that South China tigers were not as small as Mazák stated, in fact, they reached the size of the Indochinese tigers, with body length up to 190 cm and weight up to 190 kg. If @peter have more information, I will be glad to include it in the images.

Finally, I have read a few comments on the Sunda tigers, so I will post some of the old data that I have, although with a new fresh air from the newest tiger documents of Wilting and others:

1. The term "Sunda tiger" is the correct one about the island tigers, as the genetic analysis showed that they are a single subspecies. In this case, the name Panthera tigris sondaica is the correct one for the Sumatran, Java and Bali tigers. Check this comparative image, is NOT the same old one, as I added references and the size of the image of the specimens is smaller.

*This image is copyright of its original author

Now, why I scaled them smaller? Well, in my old images I used only the standing view of the animals and the measurements to scale them. Now, I used a new tool, two straight mounted skeletons of tigers, so now I modulated the images to match a real animal of those measurements. In this form, my new prepared images of tigers, lions and jaguars are somewhat smaller than the first ones, but this is because I used this new "skeleton" tool to fit them.

2. The size of the Sunda tigers is somewhat incorrect, specially for the Bali tiger. Mazák (1981 and 1983) stated that they were the smaller of the tigers with weights of barely 100 kg. Most web pages copy this idea, without knowing that there is not a single real weight of a Bali tiger in literature, and this is accepted by Mazák, although he focused in the body length, check this image:

*This image is copyright of its original author

Now, using the method of Christiansen & Harris (2009), used to estimate the weight of the giant Panthera atrox, I calculated these weights for the Bali tigers:

*This image is copyright of its original author

The table is old, the taxonomy is no longer accurate, but the calculated weights are the same. Mazák was not wrong with the females, but the males certainly were slightly heavier. Besides, Yamaguchi and his team revealed this new image of a male Bali tiger some time ago:

*This image is copyright of its original author

Its size is of the same one of an average Sumatran or Javanese tiger (compare it with my comparative image), and add to the fact that the sample used is very small (only 9 skulls, one from a subadult, and that is all), I guess that the Balinese tigers were not as small as we think and probably about the same size than the average Javanese or Sumatran tigers. Even worst (or better?), is possible that the Balinese tigers were always in contact with the Javanese population, so the few (very few) specimens recorded in the island, were a small population of Javanese tigers, impulsed by young adults that traveled to the island searching new territories. Under this new idea, Balinese tigers do not suffered from any island dwarfism, but it is just that the few specimens recorded were in the small side of the scale, that is all.

3. On the skull department, @peter reported a Sumatran skull measuring 350 mm in GLS, which is the same than the largest Javanese tiger in the wild with 349 mm in GLS. The largest Sumatran tiger skull reported by Sody (1949) was of 345 mm in GLS, and in average, the Javanese tiger is larger than the Sumatran one, although it greatly overlap in the ranges. we know that the Sumatran tigers weight between 73 - 148 kg in the wild (about the same in captivity) and Slamet, the heaviest male recorded in both hunting and scientific literature, seems to be a large but not exceptional specimen (based in the pictures of the old hunted tigers in that area), which suggest a little higher weights.

Sometime ago I stated that Javanese tigers had skulls of the same size than South Chinese tigers, which have figures between 318 - 348 mm in GLS and body weights of 130-190 kg. Now that I have have the book of Mazák "Der Tiger" (edition of 2013, reprint from 1983), I see that Mazák believed the same (pg. 172). So, I guess, based in the skull size, that Javanese tigers were as large as the South China tigers, even the variations between female skulls is minimal: female Java - 270-292 mm GLS; female South China - 273-300.5 mm GLS.

Hemmer (1987) expressed the idea that despite the large size that some male Sunda tigers could reach, they were probably lighter in weight, and compared the female Amur tigers with skulls of 280-318 mm GLS and weights of 100-167 kg with the male Javanese tigers, with skulls of 295-349 mm GLS and weights of 100-141 kg (Mazák stated a minimum of 306 mm for Javanese males). Now, the problem is that while the figures of the Amur females is accurate, that of the Javanese males is not. The range of 100-141 kg from Mazák is a mere guess, as the only weight reported in literature for a wild male Javanese tiger is of 142 kg and came from a male with a GLS of just 331 mm Taking in count that the average GLS for males in Java is of 326.3 mm, this male was close to average, not to a maximum.

Following the calculation of the weight of the Balinese tigers, using the Condylobasal length of 303 mm for the largest Javanese skull reported, I calculated a weight of 159.3 kg (using tigers only), 155 kg (using all Panthera specimens) and 155.4 kg (using the male of 331 mm GSL and 141 kg only) which is 7-11 kg heavier than the heaviest Sumatran tiger recorded at this moment (148 kg), and a weight like this is supported by the few photographs of very large Javanese male tigers hunted in the old days. This give us a good idea of how heavy could be these island tigers, however we must take in count that all the animals in the sample, apart from the Javanese male tiger, were captive specimens (normally lighter than the wild ones) and even with the wild male, it is unknown his health and physical status (only a few measurements "over curves" (?) were presented). Apart from the single wild male tiger from Java, there are also a record from a captive male at 110 kg and a female of 95 kg (Slaght et al., 2005), and this exhaust the weight figures from this population.

4. Finally, in the taxonomic side, the old classification of Mazák with three "subspecies" is obsolete. Genetic evidence suggest that the three populations belonged to the same subspecies, and this is, in fact, the only subspecies with enough genetic and morphological differences to be classified like that (Wilting et al., 2015). This is supported by the new geographic and climatic models in the study of Cooper et al. (2016), Dr Kitchener and Dr Wilting are also included in this new paper, of course.

Now, there were some previous studies, one suggested that Sumatran tigers were not different from Mainland tigers (Wenzel et al., 1999) and other that suggest that it was a different species, using the phylogenetic species concept (PSC) (Cracraft et al., 1998). Luo et al. (2004) found that this population was the most distinguished from the other ones, but it was Xue et al. (2015) and Wilting et al. (2015) which finally clarified the issue and it was accepted that Sumatran, together with Java and Bali tigers, were a single subspecies in the Sunda islands that separated from each other very recently.

On the skull issue, J. H. Mazák & Groves (2006) found that the Sumatran tigers were different from the mainland tigers, but also from the Sunda ones and proposed the idea that they were an "hybrid" between the mainland and the island population, and a latter document from J. H. Mazák (2010) proved again its difference from the mainland population, and sustain its "hybrid" status; this was the idea that I kept all this time, until now. New genetic and biogeograpic/climate studies do not support his hypothesis, and provided new evidence for the evolution of the modern tiger. Xue et al. (2015) proved that all the Sunda tigers are genetically related, just like the Caspian and the Amur tiger and differ greatly from the Mainalnd population, discarding any "hybrid" position of the Sumatran tiger, also, there is evidence that until 20,000 years ago, long after the Toba eruption, the mainland and the Sunda were still connected by large land bridges, as probably wider than Central America or the state of Florida, just to give you an idea. So, or an animal that can travel up to 1,000 km, this is a large open door to travel. The true separation between island and mainland tigers was not until the end of the last Ice Age and completely finished at about 12,000 years ago (the early Holocene) and until then, we can talk of real "subspecies". Sunda tigers started its own specialization with the slow separation of the mainland, but some "characteristics" like the narrow occiput were already present in the population and could reveal just an specialization to some predation adaptation that simply raised again when the Java-Bali tigers were isolated. Sumatran tigers characteristics are probably also adaptations to its environment, which is markedly different from that of Java, which smaller prey and deep forested habitat. This will prove that Sunda tigers are different from Mainland tigers, but also that there was no maternal genetic share between the Sunda island after this event. Now, the apparent morphological differences between Sumatran and Javanese tigers disappear if we make a deep comparison between pictures, and we see that characteristics like stripe patterns or physical "look" are superficial and irrelevant. In fact, there is also deep differences between Indian tiger populations but at the end there is not much variation in size, while the coat patter depends of the time of the year, age and physical status. Similar differences where in the Amur-Korea-Manchuria tigers, but all were of the same population.

5. Conclusion: The Sunda tigers (Panthera tigris sondaica) is one of the two subspecies of the modern tiger, it is smaller than the mainland one, and somewhat lighter at similar sizes. The old values of weights reported by Mazák need a good actualization and the skull sizes need to be taken in count for this. The three islands (Sumatra, Java and Bali) share a same ancestry (the late Pleistocene mainland tiger) and following the model of the Toba eruption of Cooper et al. (2016), an ancient population of Sunda tigers is not viable, which suggest that all the tigers, even the Sunda ones, have a mainland origin, which suggest that the old Wanhsien tiger (Panthera tigris acutidens) was in fact, the only ancestor of all the modern tigers. The characteristics of the Sunda tigers, like a narrow occiput and darker skin with more stripes, as possible just simple adaptations to its environment, with Sumatran tigers showing a few of the mainland characteristics like "atavism", while the Java-Bali tigers showed again the same type of adaptations that the first mainland tigers wave produced and that given origin to the completely extinct Ngandong tiger (Panthera tigris soloensis). However, this last part of the hypothesis could be wrong, if we take in count that the Mainland tiger subspecies (Panthera tigris acutidens) and the Sunda tiger subspecies (Panthera tigris soloensis) at the Pleistocene, kept a complete communication between them up to 20,000 years ago. The incredible of this is that if we follow this new model, and taking in count that tigers can travel up to 1,000 km in land and up to 29 kg in sea, the greatly interconnected tiger population was, at about 20,000 years ago, a single species with NO subspecies, and this population was the one that survived the Toba eruption, that given origin to both modern subspecies and its correct name most be Panthera tigris amoyensis, the original tiger, the South China tiger, and this is supported by genetic, bio-geographic and climatic models. Interestingly, after the split of the two groups, the correct name of the Mainland tigers would be Panthera tigris tigris, following the rules of Taxonomy.

Sorry for the long post, but this is what I have concluded after reading ALLLLLLLLLL these documents, old and new ones. Comments are welcomed.

Greetings to all. Reply