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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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@tigerluver
It makes sense that some tigers would digest food faster than others or eat more, etc. Metabolism can be higher or lower in humans same as animals. But Macro Nutrients required would still need to fuel animals weight. A 400lb animal would still need less food than a 500lb animal. A faster metabolism can account for some, but a person with a faster metabolism can and will still become obese if they eat fatty rich food compared to a person who eats healthier food with a slower metabolism. Since tigers are hyper carnivores, they only eat meat. So a tiger that preys on fattier prey than a tiger who preys on more densly muscled animals may be larger, but then we must take into account the energy required to take down said prey. Like somebody who works out compared to somebody that lounges around on their couch. So a tiger who hunts for himself will probably need to eat more regularly than a tiger who scavenges from his females. They use more energy so in turn they require more food. I would assume that terrain would also play a factor as if trekking is harder it will require more energy which will require more fuel. All and all, many factors will come into play for food intake but at the end, since tigers live fairly similar lives and eat a array of similar foods, I think size will be the most determining factor. Now in regards to the Bird analogy, while its usefull, a band around the leg is not the same as a collar around the neck. Also the way animals handle stress is completely different, since I don't know the history or the types of birds you speak of, its to hard to compare. But if these birds are used to human presence it makes a very different response compared to a wild animal that is used to being the top of the food chain who would have nothing to fear that may become more suseptable to stress during capture and having a foreign object placed around it. Also its much harder to capture a tiger when small and place a collar since they grow so fast and the amounts of captures required would surely stress a animal out even further. Lets not also forget the affect it would have on the tiger mother. Look what became of the Kaziranga mother when her cub was taken, she charged a forest guard on top of a elephant, so whats to keep these mothers from doing the same? A bird is far less capable of attacking a human and doing damage, so that is probably not the best comparision for this. But still appreciate the story. 
The human interference thread has been reopened. Please keep anything relevant to that debate there. This thread must stay focused on its original purpose. The data posted here is like an encyclopedia, the highlight of this place. If I've missed something, please let me know.
As per request of Peter, reposting this article, in the light that this is a text source on one approach to conservation:
Indian wild life officials make it very clear that radio-collaring is essential for the survival of tigers. Nagpur: Even as the maiden experiment by the state forest department to radio-collar two tigers in Tadoba-Andhari Tiger Reserve (TATR) has been hailed by experts in the field, it is high time such research is carried out outside protected areas (PAs) where wildcats are becoming victims of man-animal conflict. After TOI report on October 20, a section of readers claimed that looking into the death of a tigress T4 due to radio collar infection in Panna tiger reserve in MP on September 18, it is a waste of money to place satellite collars on tigers. However, wildlife experts dubbed these comments as immature. Conservationist Prafulla Bhamburkar says such research is needed more outside Tadoba landscape where 17 villagers have been mauled to death by big carnivores this year. 'Pombhurna tiger, which was shot dead, could have been saved had it been radio-collared," he added. PCCF (wildlife) Sarjan Bhagat admits that tigers outside PAs need better protection but says as of now there is no proposal to collar them. "We will moot a separate proposal," he said. Radio collar is one of the best tools to understand tiger behaviour, predation, population and ecology. Not a single tiger died of radio-collaring, because it is just 1% body weight of that species, say experts. If we want to save a species at its population level, we need to understand its ecology using reliable tools. Panna field director RS Murthy denied that T4 died of collar infection. "The tigress died naturally due to some internal health problem. It will be known once we get clinical reports from respective agencies," Murthy said. "Radio collars are the best help managers with least invasive observations of any mega carnivore. We are doing it for last five years," Murthy added. In 2009, a wildlife intelligence report had blamed tiger deaths in Panna on their 'radio collaring', raising questions over the projects to conserve the animal throughout the country. However, Bombay Natural History Society (BNHS) director Asad Rahmani says it all depends on who did it and for what purpose? Studying animal movement and ecology by radio-collaring/satellite tracking are well-known methods used all over the world. "New tracking technology is giving us remarkable results about animal behaviour and movement. So, it is wrong to say that radio-collaring per se is bad. If there is a purpose and clear objective, there is nothing wrong in radio-collaring," said Rahmani. "It is wrong to say that Panna tigress died due to radio-collaring. If this is the reason, why other animals do not die? Every major operation on human being has some risk. So, should we stop life-saving operations due to the small risk involved?" said Rahmani. In November 2012, the state wildlife wing had for the first time placed a radio collar on a rescued tigress which was released post treatment at Tass near Bhiwapur. "The collar gave valuable insights into the secretive world of big cats in the wild. Radio-tracking actually helps curb menace of poaching since tiger movement is constantly monitored and the ones which stray or are killed are immediately noticed," says wildlife biologist Vidya Athreya, who placed the collar on the Tass tigress. Athreya says there will always be accidents but with more and more such scientific activities happening, it will also allow us to improve our skills. "It is likely that the Panna tigress had a wound on her neck which the collar did not allow for healing," Athreya says. Athreya adds that in a place like Africa, where visibility is good and there are not as many people as in India, you can drive up to the animal, see it clearly and then intervene if the animal has a problem with the collar etc. "But if you ask me about the scene 10 years back and now, things with respect to understanding, management and the use of new tools have really improved in Maharashtra. I think this is a very good thing," Athreya said. http://timesofindia.indiatimes.com/city/...912773.cms As stated before, debate the article in the proper thread, I've left the original post there.
This article should go on the "hands on thread" should it not?
Unless you want me to rebutal with the fact that the FD has nothing to do with conservation and they are a private party hired by the park. Same with the fact that the tigress absolutely died due to infection from wonds suffered by her collar. Or how they used the collar to offer viewing to VP tourists and beat a tiger out of the tall grass and completely stressed the animal out. So unlesss we want to continue this debate here as well, I dont think it should be posted here.
As I said before, the article has been there as well. Rebuttals are welcome, in that thread. The article was requested by Peter to be posted here for the reason explained above. Posting the article here as well doesn't warrant a second debate here, we've rules in place for what goes where. I'm just repeating what I said in the last post here. You may post any articles here of what you have said, as after all, anything pertaining to the "edge of extinction" is fine here. Just without commentary. Any commentary belongs in our other thread.
 (11-08-2014, 03:15 AM)'Pckts' Wrote: This article should go on the "hands on thread" should it not? This article first posted by Rofl was reposted in this thread at my request. The reason is it has information on the pro's and contra's of radio-collars in tigers in some reserves in Central India. As the opinions discussed in the article could initiate a debate, it was also posted in the thread you mentioned. Debates are over there. This thread is about information.
'MOVEMENT AND ACTIVITY PATTERN OF A COLLARED TIGRESS IN A HUMAN-DOMINATED LANDSCAPE IN CENTRAL INDIA' (Athreya V., Naya R., Punjabi G.A., Linnell J.D.C., Odden M., Khetarpal S. and Ullas Karanth, K.)
1 - SOURCE Mongabay.com Open Access Journal, Tropical Conservation Science Vol 7 (1): 75-86, 2014 2 - LINK http://tropicalconservationscience.monga...86_Athreya 3 - CONTENT A tigress fell into a water duct in Nagpur district in late 2011. She was saved by Forest Department officials. After 45 days, she was released 6 km. from the place where she was found. In the first month, she stayed in the forest where she was found. Later, she moved into a nearby region that has both forests and croplands. Although she moved in an area of 726 square km., the tigress had a home range of about 431 square km., which included roads, croplands and villages in a region dominated by humans. Her main prey was wild pig (Sus scrofa). The tigress rested in dense foliage of patches of forest close to human settlements during the day and became active at night. The collar, which operated for about four months, enabled the researchers to gather information on her movement and activity pattern. The information they found is considered vital, because it is not known in what way tigers live outside protected reserves in central India. The information they found will be used to prevent conflicts between humans and tigers in human-dominated landscapes close to protected reserves. 
Excellent document and incredible information, thanks Peter.
It is INCREDIBLE how much information can we get from a single radiocollared tigress. Imagine how much data we will be able to get with more specimens. This document show how important are these type of studies and taking in count that this method is safe for tigers (if its made in a correct way), this is the next steep that authorities and scientists are going to take in the future, specially in the areas outside the protected parks and reserves. It is also great to see Dr Karanth on these studies again, as he focused mostly on camera traps and its function of estimate the tiger density and population in Nagarahole-Bandipur block. And like they say: "The information they found will be used to prevent conflicts between humans and tigers in human-dominated landscapes close to protected reserves." You can't get this with cameras alone. [img]images/smilies/wink.gif[/img] This is also important: "Very little is known about tiger ecology, and their temporal and spatial patterns of movement, outside PAs. These areas will be crucial in terms of dispersal between PAs as well as sensitive in terms of conflict" Sadly, they don't published the body measurements and weight of the tigress, it would be useful for comparison with the single tigress (Sundari - T-102) captured in Nagarahole. (11-08-2014, 03:15 AM)'Pckts' Wrote: This article should go on the "hands on thread" should it not? Why you are continuing this debate here? If you have respect for Peter and his topic, stop posting this type of comments here. You have already a place for that: http://wildfact.com/forum/topic-eyes-on-...65#pid6165 Thank you. However, let's clarify: * The people that actually worked with those tigers say that the tigress did not die from the radiocollar. This is interesting, as we can see that the early report that the tigress died in that way was probably incorrect (or false). We most be pragmatic, we are only reading about the event, none of us was actually there. It is unfair to blame someone without evidence. * On the use of radiocollars for tourists. Well, that is a bad practice, but this doesn't mean that radiocollaring is bad, only that the people is using a useful tool in a bad way.
ORIGINAL POSTS
Our forum has different departments. There's the forum itself, there's a department for wildlife photographers and there the department for blogs. In the end, it is about quality and, as important, originality. Original photographs, articles, tables and posts, for different reasons, are much appreciated. BIG CAT EVOLUTION In the last two decades in particular, as a result of new techniques, quite many articles on the evolution of big cats have been published by talented and dedicated researchers. As every researcher had a slightly different angle or perspective, the result of their quest, I think, is fascinating. This post is an original on tiger evolution. It's an attempt to get to a kind of overview and it's based on the effort of the researchers mentioned at the end. As I have to assume mistakes were made in some way or another (typos included), I decided to add a number to every piece of information discussed. Anyone interested is invited to respond or correct mistakes. The summary was first posted in post post 75. When I saw the scans were below par, I decided to withdraw the post entirely. This, therefore, is a repost of post 75. If you're interested, I would advice to read post 76 as well. That post has two maps offering a bit of insight in tiger distribution about 100.000 years ago. Here we go.  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
BIG CAT EVOLUTION - II
This post is a continuation of the previous one. It has a number of illustrations that belong to the summary in the previous post. Some are directly related to a distinct part in the text, but most are not. I used a pair of scissors to cut every table, map or photograph I wanted to use for the summary. I then used tape to get the result to the page. After that, every page was scanned in a way that showed the image as clear as possible. This means the page number is in a different position every time. It also explains why some pages are larger than others. I agree it's a bit rude, but it does the job. THE RELATION BETWEEN TIGER SIZE AND HERBIVORE SIZE I was surprised by the recent discovery of cat skulls in Tibet. It could mean our idea about big cat evolution has to be revised. I also was surprised by the size and robustness of some of the Pleistocene tiger skulls found in central and northern China. I measured and photographed over 350 skulls myself and never saw something even close in robustness. The owners of these skulls must have been very large animals. The only tigers that seem to be in the same league today, I think, are those living in north-east India. The difference with other tiger regions is north-east India is the only place where tigers still live next to very large herbivores. In contrast to what many think, some of these tigers really specialize on some of these big herbivores. Immatures are targeted mostly, but adults also are killed at times. This, I think, could explain why some of the Pleistocene tigers were large animals: the larger the herbivores, the larger the tiger. One could say large size probably was a result of plenty of food, but I think tigers really hunted large herbivores. They still do in north-east India. Any proof? No. But there is circumstantial evidence. The bison-hunting wolves in Canada are larger than anywhere else. Brown bears feasting on salmon in coastal regions are larger than relatives living in other regions. Polar bears are the largest of all bears. Proteine no doubt is the drive in size, but that doesn't mean predators feasting on large animals are scavengers. The extra size they have is a result of hunting large animals, I think. Protein is a deceiving factor, that is.  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
KAZIRANGA TIGERS
This post is an illustration of some of the notions on prey size and tiger size discussed in the previous post. Female 1:  *This image is copyright of its original author Female 2:  *This image is copyright of its original author Female 3:  *This image is copyright of its original author Female 4:  *This image is copyright of its original author Male 1:  *This image is copyright of its original author Male 2:  *This image is copyright of its original author Male 3:  *This image is copyright of its original author Male 4:  *This image is copyright of its original author Male 5:  *This image is copyright of its original author Male 6:  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author Male 7:  *This image is copyright of its original author Male 8:  *This image is copyright of its original author Nearly all tigers seem heavy and robust animals, even females. It could have been a result of selection, angles or circumstances, but chances are Kazirangha tigers are robust animals with large skulls. As the main difference with other regions is in the sheer numbers of large herbivores, one would think the most logical explanation for the large size would be plenty of food. However. Reliable information on tigers hunting large immature herbivores and, at times, even adults suggests the large size could be an adaption to the size of the prey animals. This means they could hunt them more often than we think.
That is great summary Peter. I most read it today, that is for sure.
Just one thing, I have noted (in the internet mostly) that there is a common myth that the Wanhsien tiger (Panthera tigris acutidens) was larger and more robust than the Ngandong tiger (Panthera tigris soloensis), but this is incorrect. The only base for that is that the metapodials of the northern subspecies were larger and more robust than those of the south. However, this is not enough evidence as Bengal tigers had relative smaller paws in comparison with the Amur tigers and they are still much heavier than they northern counterparts. Besides the few long bones recorded from China show that they were not exceptionally robust, in comparison with other specimens. Based on the few fossils available, the largest Wanhsien tiger was about the same size than the largest Amur-Bengal tigers on record, with an estimated weight of up to c.270 kg. In this case, the only tiger that surpass the 360 kg was the Ngandong tiger with estimated figures of up to c.370 kg (based in several formulas) and probably c.400 kg acording with Tigerluver. The only fossil that suggest an exceptional size are the huge skull and the mandible from northern China. We have compared them with other specimens and even cave lions, but the result was that the mandible had a match with the tigers from Java, suggesting a link between them. On the skull, I made a previous estimation and the skull probably measured 442 x 293 mm (length x wide). If this is the case, this specimen was among the largest on record, been only 6 cm less than the largest Cromerian lion skull, which in big cats, is a irrelevant difference. This size is about the same that the estimated skull length for the largest femur from Java (skull of c.440 mm). In this case, they should be of the same size, in the best case, but as we don't know the real size of the Chinese skull and if we base our data only on the known fossils, the Wanshien tiger was not larger than the Javanese counterpart.
On the Ngandong tiger weight, after my database increase and new measurements, both 370 kg (this estimate is composed of invalid equation anyhow, the disregard to allometry is the major problem) and 400 kg (I had a smaller database at the time) estimates are likely very off. I think I posted the data in the prehistoric felids thread. The largest of the Wahnsien specimens approached 300 kg, assuming the dentition proportion were not greatly different than modern forms. The largest Ngandong specimen was between 409 kg (based on length) - 531 kg (based on diameter, interestingly this mass is still this great even using quite negative allometry), or 470 kg averaging the values. Remember, a weight seeming very high doesn't mean its an exaggeration if its mathematically backed. There was serious gigantism across the board in the Pleistocene.
 (11-08-2014, 07:23 PM)'GuateGojira' Wrote: That is great summary Peter. I most read it today, that is for sure. The largest cromerian lion skull is about 485mm, but they were not very robust built. |
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