(02-28-2025, 06:31 AM)peter Wrote: APEX

Yet another long, well-prepared and interesting post about tigers and bears in the Russian Far East. Must have taken quite a bit of time. Effort much appreciated! 

I assume you're aware of the video about interactions between tigers and bears in the Russian Far East recently uploaded on YouTube by Prof. S. Wroe? I made a few notes and will discuss it in some time: 

https://www.youtube.com/watch?v=_mcKIpZW9qs

In his video, Prof. Wroe discusses three issues also often discussed at forums: size, bite force and reliable reports about the outcome of interactions. 

Although the info on size seems a bit outdated (he uses information collected in the period 1992-2002 or thereabout), it's reliable. 

Most adult male Amur tigers today, depending on their condition and the season, range between 360-442 pounds (163,3-200,5 kg). Both Batalov and Fomenko said a male exceeding that mark (442 pounds or 200,5 kg) is large in most districts. Adult male Ussuri brown bears, depending on the district and the season, average 575-595 pounds (260,8-269,8 kg). 

Individuals well exceeding these markers (referring to both species) have been weighed, but they're few. For now, it's safe to assume an exceptional wild male Amur tiger can reach 270 kg (596 pounds, Feng Limin), whereas an exceptional male Ussuri brown bear can reach 362,88 kg (800 pounds, WCS).

According to Wroe, who knows a few things about bones, the bite force of tigers exceeds that of brown bears by about 20%. The percentage, as Warsaw stated, is questionable, but it isn't about the details. What Wroe is saying is tigers, biteforcewise, have an advantage. That's still without the canines. If we add speed and agility, one could conclude an average adult male Amur tiger roughly compares to a larger male brown bear in most respects. Tigers and brown bears seem to agree. The result is mutual avoidance. 

Some male bears follow and rob tigers, but they tend to select females (with cubs) and, perhaps, (young and/or old) males with problems. And the other way round: experienced male tigers interested in bears, as you stated, tend to select female brown bears up to about their own size (weight). The recent incidents discussed in this thread strongly suggest male brown bears are sometimes hunted as well. All in all, one could conclude Amur tigers are quite prolific bear hunters, not the other way round. Russian biologists did find overwhelming evidence of tigers killed by brown bears, but not in the period 1992-2025.        

Prof. Wroe's video didn't go unnoticed. I recently visited 'Domain of the Bears' and 'Carnivora' and noticed Warsaw is preparing for battle. You can have a go at prof. Wroe's video if you like, but when you post about it in this thread make sure you focus on information, not something else.   

At the moment, I'm investing most of my energy in skulls and conflicts (between man and tiger). I recently found a video in which a young adult male features. He was shot (by poachers) and, most unfortunately, perished. Another male, adult but still quite young (referring to the teeth), was injured in a fight. He needed medical assistence and was sent to rehab.

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(03-02-2025, 07:40 PM)return 80 Wrote:

The SOB and OH of tigers

The Supraoccipital breadth(SOB) relative to the Occipital height(OH) In previous studies, it was considered a significant distinguishing feature between different subspecies of tigers, and even now it has at least valuable population identification significance.

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In tigers, the relative width of SOB can be clearly defined as gradually increasing from south to north on the Asian continent, which seems to be a functional adaptation caused by their corresponding ecological environment.

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However, there does not seem to be much data on SOB in the literature, and it is generally not a major measurement value.

Its measurement method is"the smallest distance between notches of lateral margins of the occiput; the notch being situated approximately where sutura occipitoparietalis, sutura parietotemporalis and sutura occipitotemporalis meet"(Ji H. mazák 2008)

I have seen a good structural diagram(see blow, Narimane Chatar et al.2022) that can clearly distinguish these bone sutures. Please pay attention to the intersection of the occipital and parietal and the temporal in the diagram.

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In the posterior view provided by Ji H. mazak, the specific location is the highest point on the dorsal side of the mastoid process And the Dorsal view can be seen in Figure B. Búzás and B. Farkas 1996.

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In the publications of V. mazák and Ji H. mazák, it seems that I can only find specific data on island tigers and indochinese tigers (including Malayan tigers)

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However, in his publication<Recent Advance in Tiger Phylogeny, In the Evolution and Geographical Variation >(Chinese version), he listed the scatter plot data of male SOB for all subspecies.

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According to the scatter plot, we can see that the Amur tiger has a significantly widest SOB, both in terms of relative width and absolute width.Corresponding to the logarithmic axis of SOB, the SOB of some particularly wide male Amur tiger individuals may even reach around 90mm, almost 1.8 to 2 times that of some small Java and Bali tigers.

One of the male Sumatran tigers is very interesting, with a maximum recorded SOB of 83.4mm. Such a huge size makes it easy to find in scatter plots. From the graph, it can be seen that its SOB is almost as wide as the widest male Bengal tiger and comparable to many male Amur tiger individuals, which is very astonishing.

*This image is copyright of its original author

(Yesterday, 03:54 PM)return 80 Wrote:

(03-02-2025, 07:40 PM)return 80 Wrote:

The SOB and OH of tigers

The Supraoccipital breadth(SOB) relative to the Occipital height(OH) In previous studies, it was considered a significant distinguishing feature between different subspecies of tigers, and even now it has at least valuable population identification significance.

*This image is copyright of its original author

In tigers, the relative width of SOB can be clearly defined as gradually increasing from south to north on the Asian continent, which seems to be a functional adaptation caused by their corresponding ecological environment.

*This image is copyright of its original author

However, there does not seem to be much data on SOB in the literature, and it is generally not a major measurement value.

Its measurement method is"the smallest distance between notches of lateral margins of the occiput; the notch being situated approximately where sutura occipitoparietalis, sutura parietotemporalis and sutura occipitotemporalis meet"(Ji H. mazák 2008)

I have seen a good structural diagram(see blow, Narimane Chatar et al.2022) that can clearly distinguish these bone sutures. Please pay attention to the intersection of the occipital and parietal and the temporal in the diagram.

*This image is copyright of its original author

In the posterior view provided by Ji H. mazak, the specific location is the highest point on the dorsal side of the mastoid process And the Dorsal view can be seen in Figure B. Búzás and B. Farkas 1996.

*This image is copyright of its original author

In the publications of V. mazák and Ji H. mazák, it seems that I can only find specific data on island tigers and indochinese tigers (including Malayan tigers)

*This image is copyright of its original author

However, in his publication<Recent Advance in Tiger Phylogeny, In the Evolution and Geographical Variation >(Chinese version), he listed the scatter plot data of male SOB for all subspecies.

*This image is copyright of its original author

According to the scatter plot, we can see that the Amur tiger has a significantly widest SOB, both in terms of relative width and absolute width.Corresponding to the logarithmic axis of SOB, the SOB of some particularly wide male Amur tiger individuals may even reach around 90mm, almost 1.8 to 2 times that of some small Java and Bali tigers.

One of the male Sumatran tigers is very interesting, with a maximum recorded SOB of 83.4mm. Such a huge size makes it easy to find in scatter plots. From the graph, it can be seen that its SOB is almost as wide as the widest male Bengal tiger and comparable to many male Amur tiger individuals, which is very astonishing.

The two posts I previously posted only explained some phenomenon reports, but did not provide content explanations. Indeed, this is very necessary, so here I share some of my views

Although Hasegawa has reported multiple tiger fossils sites from Japan, unfortunately, these materials have not been systematically organized, so I can only provide some speculations on why Shiriyazaki's Late Pleistocene tigers were so large. 

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According to the ecological geographic model of tiger populations by Luo et al. 2024(https://doi.org/10.1038/s41559-023-02185-8), we can see that during the LGM (Last Glacial Maximum,Fig.B), Japan was connected to the Asian continent due to sea level decline, and at this time, Japan was also a high probability habitat suitable for tigers (red area).

Some of tigers may have migrated from China to Japan, and very large tiger fossils were also discovered during the last interglacial period(Fig.A) and the LGM in region 2(These habitats, which are considered highly likely to be suitable for tigers, have also yielded large tiger fossils in many locations). However, due to the long-term interglacial and glacial replacement during the whole Pleistocene, tiger fossils in other Pleistocene sites in Japan may be relatively small (as Peter pointed out, island dwarfism may have occurred at specific times that Japan is not connected to the Asian continent).

The second one is about the explanation of the occipital.At first, when I posted this related context, I just wanted to explain some data, but personally, I also have my own views on this phenomenon.

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Generally speaking, the occipital is directly related to the very important occlusal muscle - the temporalis muscle. In northern tigers (Amur tigers and Caspian tigers), the sagittal crest is also very developed, which indicates the need for strengthening their occlusal muscles. Amur tigers have the strongest sagittal crest and widest occipital. Relatively speaking, although the Caspian tiger is very developed, it is not as exaggerated as the Amur tiger. My viewpoint is that the size of SOB is the same as the level of development of the sagittal crest, which is also an evolutionary feature supporting the theory that Amur tigers need to gnaw on frozen meat in extremely cold regions.The same example can be seen in cave lions, where these Pleistocene cats can even be distributed within the Arctic Circle, and many of them also have very wide occipital.

This feature is not entirely related to body size, as the largest tiger in history, Panthera tigris soloensis, like Java tiger and Bali tiger, has relatively thin occipital, while the Sumatran tiger is believed to have been formed by natural hybridization between continental and island tigers, although this theory still requires more evidence

The above are some of my opinions. Everyone could share your idea~

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