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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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I agree the Russian article is quite convincing. It proves using foot-snares can be risky. I'm not sure, but I remember reading a post in which it was stated that the procedure had been changed. To a degree. They still use foot-snares to capture wild Amur tigers, but it's done in a slightly different way. I didn't read anything about problems so far.
My advice is to contact Miquelle and ask him a few questions on the method used today. I'm interested. Foot-snares could be a thing of the past in some years from now. In African reserves, drones are now used to monitor wild animals. They're still testing, but those involved in the project were quite positive. Poachers most probably are not, but something has to be done. A few days ago, I read a report about elephant poaching in Africa. It was even worse than they thought. If we add Packer's view on the future of wild lions (see my last post in the extinction thread on lions), the conclusion is things have to change. If you visit Africa, ask them about poaching and the use of drones. Record what you can. Enjoy your trip and buy a tape before you go. You never know. 
I will definitely ask about poaching, that is something that interests me quite a bit, especially from the ground floor perspective. I'm also interested in the effects of vulture numbers decreasing, I leave on Tuesday and I hope to come back with a much more enlightened perspective.
In regards to capture, if new, less invasive ways are developed, I'm all for it. I'm not sure if there will ever be a totally "animal-safe" way of capture though, I'd like to see that changed but every failed attempt hopefully leads to a better way.  (09-04-2016, 06:39 PM)peter Wrote: The robust arches, the long and elevated snout and the width of the upper canines strongly suggest the skull belonged to a wild male. In spite of that, I propose to wait for more information. As collectors often communicate about skulls, chances are there could be a magazine. If so, we got to find it. I got the impression that this wild male might be a victim of the rampant poaching activities back in the 20th century when the conservation effort was even weaker than now.
"Quite many skulls I saw had similar dark-yellow and brown parts. In most cases, it turned out to be fat. This means the owner had died not that long ago. Although fat can remain for many decades, fossil skulls, as far as I know, never had any."
@peter Some skull that remained unclean for decades whose decayed flesh/fat could turn into dark brown color. What is your opinion regarding to the 6.6 inches Amur tiger upper canine tooth?  *This image is copyright of its original author
Tiger body mass underestimated in historical records
After reading numerous records, I noticed that many hunters have weighed there tigers in different ways. Some hunters have even weighed there tigers in small pieces. This causes a problem, cutting up and weighing an animal in small pieces causes the animal to loss its blood weight, resulting in a reduction in its mass. Keep in mind, blood alone makes up approximately ~7% of the body weight of an organism. Peter or Guate, what do you think? Baker (1890) gives the weight of one tiger that we shot as 437 lbs, but he later took into account that the animal he shot have lost a significant amount of blood, estimated at 10 lbs.  *This image is copyright of its original author Other hunters that have weighed tigers have not only shot there tigers causing them to bleed out before weighing, but have even cut there animal into small pieces... Hornaday (1891) gives the weight of one tiger at 495 lbs, but there is a problem, check out how he weighed the tiger...  *This image is copyright of its original author And as far as I've seen, he isn't the only one that did this. Thoughts?  (09-05-2016, 05:51 AM)GrizzlyClaws Wrote: "Quite many skulls I saw had similar dark-yellow and brown parts. In most cases, it turned out to be fat. This means the owner had died not that long ago. Although fat can remain for many decades, fossil skulls, as far as I know, never had any." 1 - AMUR TIGER CANINE The upper canine is 77-78 mm. in greatest length measured in a straight line from the gum line to the tip. At least 4 mm. or 5-6% longer than the longest I measured. The width at the gum line is unsurpassed (exceeding 40 mm.), meaning it's likely the canine belonged to a wild male Amur tiger. As canine length and skull length seem to be related in captive Amur tigers, it's likely the skull would have been very close to 380,00 mm. in greatest total length if the owner would have been a captive male. As it's likely the relation between skull length and upper canine length is similar in wild Amur tigers, chances are the skull would have been well past that mark if the owner would have been a wild animal. Judging from the photograph you posted, chances are the tiger was a wild male. Tigerluver couldn't find a positive link between greatest skull length and head-body length and weight in wild tigers, but his sample could have been too small. The WCS-table with measurements of wild Amur tigers suggested there could be a positive link between head length and head-body length. Based on the info I have on other tiger subspecies, I think there is, albeit not a strong one. The best indicator of weight seems to be skull width. If I was to say a few words on the size of the owner of the canine you posted, I'd say he most probably was at least 200 cm. in head and body length (measured in a straight line). Weight would be another matter for the reason stated above (skull width). 2 - FAT AND DISCOLOURATION IN TIGER SKULLS Most of the skulls I measured were discoloured because they had not been defatted. Some of the skulls were nearly black and all of them were heavier than defatted skulls of similar age and length. The oldest (discoloured) skull I saw was acquired in the early stages of the 19th century, meaning a skull can remain discoloured for a very long time if it wasn't defatted. All very old skulls I saw (older than, say, 250 years), however, had no fat. Same for fossil skulls. 3 - THE EFFECT OF PRESSURE ON INDIVIDUAL VARIATION IN TIGERS Skulls of Sumatran male tigers average just over 310 mm. in greatest total length and just over 1 kg. in weight. Skulls of old males, however, are decidedly longer and heavier than those of young adult males. The longest I measured was exactly 350 mm. in greatest total length. This skull was defatted and almost 2 kg. in weight. Based on what I saw, I concluded individual variation is more pronounced in Sumatran tigers than in all other subspecies. At least, in skulls. Javan tigers, on the other hand, show little variation. Same for Amur tigers. The question is why. Skulls of Javan tigers were acquired just before they disappeared, whereas the Amur skulls I measured belonged to tigers who descended from those who just survived the bottleneck in the first half of the last century. The conclusion for now is pressure and low numbers apparently result in a lack of individual variation in wild tigers. A lack of individual variation, therefore, is a sure sign of problems. Why was it not announced in Sumatran tiger skulls? The answer is nearly all skulls I measured were collected before 1950. Sumatran tigers most probably thrived until that date, that is. Their collapse, therefore, is of recent origin.
@peter
1. His natural gum line is about 77-78 mm, but when the tiger has reached his adulthood, his gum will start to recede, so his gum line will move upward to 80 mm. And his canine diameter also by far exceeds the 383 mm wild skull measured by Mazak. Do you think the magnitude of his size could be on par with the Duisburg specimen and the wild giant mentioned by Jankowski? 2. That's what I thought, those non-defatted skulls could be less than a century, and the even older skulls would be naturally defatted. 3. So the tiger skulls should also show some morphological diversity, right? Otherwise, maybe it is a sign of inbreeding because of the smaller remaining population? 
Social structure and space use of Amur tigers (Panthera tigris altaica) in Southern Russian Far East based on GPS telemetry data
An interesting study that shows some unique behaviors for the selected Amur tiger populations. While males have distinct core areas, there are more males in one area as compared to other tiger populations, indicating that male compete in a scramble of sorts for mates. (09-10-2016, 08:16 AM)Kingtheropod Wrote: Tiger body mass underestimated in historical records Well, here I go. Contrary to popular belief, weights of wild animals are not as common as measurements, and its reliability depends of the scale used and the state of the animal (full or empty), also the health state and other natural factors. These cases show that many times, hunters are unable to carry large scales and they used this type of method to "estimate", piece by piece, the weight of its specimens, and this was common in Africa and Asia. Interestingly, this is the "normal" case of all cetaceans, as just a few, very few, large specimens had been weighed completely, mostly are weighed in pieces and that is why a blue whale of 170 metric tons could weights up to 200 ton in real life. With tigers, this are not rare cases. Burton weighed a huge tiger know as the "Ambari male" with a scale of just 500 lb, and he calculated that the animal probably weighed 50 lb more, a total of 550 lb (249.5 kg). Dr Sunquist had a scale of just 500 lb during his studies in Nepal so he never could get the real weight of the Sauraha male (M-105) and all the Sambar male deers that he captured. Later, Dr Dave Smith carried a scale of 600 lb (272 kg) and even then, the Sauraha male and the male M-126 bottom it to! Captain W. H. Hunter also used a scale of 513 lb and a little one of 50 lb, but even then, his largest tiger bottomed both (male of over 563 lb (255.4 kg+), in central India). Finally, the Maharaja of Cooch Behar once weighed a tiger with a incorrect scale, and latter he estimated a higher figure, based in a Sambar weighed with both scales (sorry, I don't remember the weight). As we can see, there are several cases of tigers been underestimated in weight because of the scales used and the circumstances of the hunt. We most take in count that, if we actually take in count these situations, is possible that many weights of lions and tigers in old literature were taken in this form, but as there is no description, we can't take actions over them. Even in modern days, we know cases of animals been weighed with bad scales. Remember the case of the lion Puyol of 235 kg (the same investigator accepted the fact that the scale was barely reliable), or the resent two tigers of 85 kg and 185 kg in Central India, which seems incorrectly weighed. Some people like Waveriders want to make us to believe that ALL scientists in the field make its measurements following established protocols at 100%, but that is not true, as circumstances and even the criteria of each investigator influence the results. There is always variations, and not all the people is guided "by the book". So, I will quote Dr Sunquist, saying that if anyone is going to discard some "tiger weights" because they don't fall in its "golden protocols", then we should investigate all the weights of lions, jaguars, leopards, etc. etc., that don't follow it too, and discard them. That is why I am not agree in discarding skull measurements just because a pair of posters (both with "W") are not agree and just because they don't like the results, or don't fit into they stereotypes. We can't corroborate the accuracy at 100%, fair to say, but also we can't discard its accuracy, specially when is stated the method of measurement. If we are going to play fair, we most use the same criteria, with ALL the animals, tiger-lions-bears by equal. There are no such thing as 100% or "crystal clear" measurements, that are nonsense. The best we can do is to believe in the descriptions of the procedures and use our own criteria to estimate its reliability. In this case, the scientists of the Siberian Tiger Project and other experts made a great work in the chapter 6 of the Amur tiger monograph, stating a clear and reliable protocol of four steeps to state which figures (weights and measurements) are reliable and which not. Let's see what Peter can add here. (09-10-2016, 11:25 PM)GrizzlyClaws Wrote: @peter 1 - Likely. The reason is the positive correlation between canine length and skull length in skulls of captive adult male Amur tigers. As I also think there is a positive correlation between body length and skull length, chances are the owner of the canine you posted was a very large male tiger. He could have been similar in size to the giants you mentioned, as skulls of wild tigers often are a bit longer than skulls of captive animals. Even if we allow for the effect of individual variation, the tiger must have been a very large animal. The length of the upper canine is impressive, but it is the width at the gum line in particular which is remarkable. It's over 30% wider than the biggest upper canines I measured (...). As there is a strong correlation between width and status (captive or wild) in tigers, it's very likely the owner of the canine was a wild male. 2 - It's difficult to get to a statement, but I'd say it could be well over a century. In most cases, however, it's less. The difference in weight between a defatted skull and one of similar size and structure that wasn't often is significant. 3 - Yes, skulls of wild tigers often show quite a bit of individual variation. Same for other big cats. When individual variation is very limited or almost lacking, there often is a problem. Skulls are the best means to argue against captivity. Compared to skulls of wild tigers, many skulls of captive tigers, apart from being shorter, wider and less elevated, are asymmetrical. Teethwise, the difference often is very outspoken. One could say these skulls are an expression of illness. I saw quite a number of skulls of adult captive big cats who perished as a result of illness when they had reached adulthood. They were shorter and smaller as a rule, less dense, not as heavy, not completely developed and not seldom quite asymmetrical. If one would describe skulls of healthy adult wild big cats as muscular and well developed, skulls of many captive big cats should be described as parodies. The difference often can be seen at a glance. (09-11-2016, 07:40 AM)tigerluver Wrote: Social structure and space use of Amur tigers (Panthera tigris altaica) in Southern Russian Far East based on GPS telemetry data Thanks for the link. The study is interesting, as it not only shows patterns we didn't know about. It also shows in what way specific local conditions, habitat destruction and prey depletion affect behaviour in a tiger subspecies living on the edge. Amur tigers, and males in particular, need a lot of space. Over a century ago, adult males needed 4-14 days to patrol their home range in India. This was in the days of plenty in a densely forested and well-stocked region. Amur males need more time, which allowed other males a chance to use a part of their territory. This situation apparently can continue for years. Although it could seem different, Amur males with a territory seem to be as territorial as Indian tigers. Based on what I read, I concluded humans and bears also are seen as (permanent) competitors. Conflicts between Amur tigers and bears often are explained as results of food disputes, but territory could be more important than we think.
@peter
A 2200 years old Amur fang, but unfortunately there is no benchmark comparison with a caliper. And the fang alongside is a huge Asiatic Black bear. This subfossil Amur fang looks quite similar to the aforementioned 6.5+ inches Amur fang. Maybe the ecosystem was once more suitable for those 300 kg giants to thrive.  *This image is copyright of its original author The Sumatran fang can also attain a remarkable size. The only major difference that it is usually more curved as the root part compared to those mainland subspecies such as Amur tiger and South China tiger.  *This image is copyright of its original author
A FEW PICTURES OF LION AND TIGER SKULLS
Tigerluver lost a photograph of a skull of a Javan tiger and asked for a new one. I decided to post a few more in order to enable a comparison. As I'm renovating the house and lost view of what is where, I'm unable to provide details. Remember the photographs are not up to scale, so don't try to get to conclusions on size. The photographs are not about size, but about the features typical for the two species and the different tiger subspecies. It also is about the difference between skulls of captive big cats and skulls of wild big cats. Wild big cats usually have slightly longer, more elevated and more dense skulls and much larger teeth. Uppercaninewise, the difference often is significant. Of those I measured, the lion skull (no. 06) was the longest (greatest total length), whereas the skull of the wild male Indian tiger (no. 05), slightly shorter, was the widest. It also was the most robust. The skull of the wild male Amur tiger (no. 08) was a bit longer than the skull of the lion (no. 06). The post is finished with a few comparisons posted before. Here we go: 01 - Javan tiger (Panthera tigris sondaica) - adult wild male - mandibula concave:  *This image is copyright of its original author 02 - Sumatran tiger (Panthera tigris sumatrae) - adult wild male - mandibula nearly straight:  *This image is copyright of its original author 03 - Amur tiger (Panthera tigris altaica) - captive, old female - mandibula concave:  *This image is copyright of its original author 04 - Indian tiger (Panthera tigris tigris) - captive, old male - mandibula nearly straight:  *This image is copyright of its original author 05 - Indian tiger (Panthera tigris tigris) - wild adult male - mandibula nearly straight (the occiput was broken and reconstructed):  *This image is copyright of its original author 06 - Lion (Panthera leo leo) - adult captive male - mandibula convex:  *This image is copyright of its original author 07 - Amur tiger (Panthera tigris altaica) - adult captive male - mandibula concave (in most male skulls, the mandibula is nearly straight):  *This image is copyright of its original author 08 - Amur tiger (Panthera tigris altaica) - old wild male - mandibula straight):  *This image is copyright of its original author 09 - Indian tiger (Panthera tigris tigris), adult wild male (left) - Indian lion (Panthera leo persica), adult wild male (right):  *This image is copyright of its original author 10 - African lion (Panthera leo leo), adult wild male (top) - Amur tiger (Panthera tigris altaica), adult captive male (bottom):  *This image is copyright of its original author
That wild male Bengal looks massive.
It would be better with the measurement and weight for the new skulls. |
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