I can’t believe it!!! How did you know that? It is simply
devastating for the science!!!
Now about the size issue, I think that is completely
plausible for the Wanhsien tiger to reach the extreme size of the Ngandong
tigers, after all, it were they genes which give the huge size to the large Sunda
tigers in the Pleistocene.
Thinking a little deeper, if we take the
evidence like it is, the Amur tigers are the less related with the Wanhsien
tiger of all the modern tiger subspecies (including those from the Sunda
region). Remember that they evolved about 10,000 years when they invaded the
Central Asia region via the Gansu Corridor (Silk Road), ranging from Anatolia
to the Russian Far East and this range became discontinuous recently, within
the last 200 years, probably through human agency (Driscoll et al., 2009).
So, why the large size in the Baikal tiger?
Well, I think that the large size is not a particular characteristic of Amur
tigers. If we see the pictures of some Bengal tigers in the old hunting literature,
they show very large tigers like for example, the huge Bachelor of Powalgarh.
I believe that the large genes were always in
all tiger populations, but habitat, climate and prey base modeled the
morphology of the tiger, check this points:
1. Habitat: Amur and Bengal tigers, both in completely
distant areas, reach the largest sizes, but the middle populations (Indochina
and South China) are rater smaller. The heavy jungle of China and the Indochina
region probably caused a diminish in tiger size (like Tigerluver stated) and
taking in count that even a 140 kg Javanese tiger can kill a Banteng of 800 kg,
it seems that size is not too crucial for the tiger as a predator. The woods of
Russia and India are less closed and even Nepal, which have large grass areas, those
with many trees are avoided by tigers. It seems that the “closed” areas are not
the best habitat to develop large sizes. Even the Caspian region, which was
closed only by the large grass, it had small wooded area and whit this, the
tiger population in that area reached about the same size than the large
specimens of India and Amur.
2. Climate: This is a great factor that had always
affected mammals. Even when the Bergsman’s rule has been discredited in some
circles, we can’t deny that northern animals tend to be larger than the
southern ones. However, this seems more tied to the temperature than to the latitude.
Amur tigers are without a question the largest tiger subspecies and are only matched
by the Bengal ones, however not all Indian tigers are as large. For example,
those from Hyderabad are barely larger than those from Indochina and Burma, those
from Nagarahole-Bandipur region are long and tall but lighter than those from
Central India and those from Sundarbans are as small as the Bali tigers. The
champions are those of the Terai region (North India, Nepal, Bhutan and the
Assam) with the real records coming from this area (Bandhavgarh tigers are
large, but Kaziranga are HUGE).
3. Prey base: This seems to be fundamental to the
develop of tiger populations, after all, Indochinese tigers are now very small
compared with Bengals and they reproduction is much less than those of high
prey density regions. However the tigers of Panna for example, which live with
heavy chital deer (av. 50 kg) population and low large herbivores density,
reach much large weights than those from Nagarahole-Bandipur with large
populations of mega-herbivores like gaur and even elephants. The Amur tigers
live in an area with smaller prey than that of Java, but even then, they are
larger. Other thing is the adaptation: if you see the skull of an Amur tiger,
they have larger muzzle and the largest sagital crest of all populations (together
with the Caspian ones), which seems an adaptation to kill the heavy dangerous
wild boars. This type of prey seems to produce larger skulls in Russian tigers than
the Bengal ones. Even when the Bengal population has the longest skull record, the
overall measurements of the longest Amur tiger skull recorded, proves that this
specimen is larger and probably much heavier. Then, the head of Amur tigers is
larger than those of the Bengal, Mazák stated that the head (with the flesh) constitute
1/5 of the head body length in the larger specimens.
Resuming, the giant genes are in all the tiger
populations, but the habitat, climate and prey (although this with less degree)
caused that only two populations produced large sizes. The Baikal tiger is probably
one of the last examples of the past, but this could be also just a case of
gigantism, just like the Jaipur tiger.
To put it simple, a tiger of 200-210 cm (head-body,
no tail) is a large one, 211-221 cm is a huge one and up to 230-240 cm (like Baikal)
is an exceptional and “one in a hundred” case. Weights are different, as it
depends of the feeding, the exercise and the metabolism of each cat. Check that
the large Shere Khan tiger weigh over 700 lb (also actually weighed) but it
looks very fat, while Baikal weigh 850 lb and looks pretty muscular and