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

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RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - Wolverine - 11-09-2018


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RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - epaiva - 11-10-2018

Credit to @wildrussiantour

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RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - Wolverine - 11-10-2018

@Pckts maybe after Pantanal your next adventure will be following of Amur tigers with snowmobile with the tour agency of Ms Olga Krasnykh?


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - paul cooper - 11-10-2018

(11-10-2018, 07:34 AM)epaiva Wrote: Credit to @wildrussiantour

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The first pic is a tigress in captivity..


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - Olga.bohai - 11-14-2018

(11-10-2018, 09:36 AM)paul cooper Wrote: The first pic is a tigress in captivity..

You're right. That was my mistake and I posted it about 3 years ago before we started wild cats watching tours, those days I didn't understand the difference. 

Now we usually post pics from the camera traps and photographers'.
These photos (link below) are from the hunting club next to Lazo reserve and not of good quality.
Tiger came to the hunting club's field where hunter was waiting for a boar. So this tiger was against the hunting for his prey))
The owner of the hunting club is an old man and he can only use film camera as you can see))
We have a lot of photos from camera traps in Leopard Land National Park, both Amur leopards and Siberian tigers. We can post them here when we have enough time.

https://drive.google.com/open?id=1PKyLOk3NLBPAaIA_7cyRt2icGquyhFnb


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - Olga.bohai - 11-14-2018

For the last three days we've got information about 3 tigers in Primorsky krai which came out on the road. This video is about 2 of them:





Locals are excited because there are a lot of cases when tigers came out from the taiga last years. And many people don't understand this tiger's behavior, they're afraid for their cows and dogs, the quantity of conflicts rises nowadays.
In my opinion tigers always behaved like that but today everybody has smartphone, DVR and Internet in their villages, just more information and communication between people. The same situation with sharks. People didn't know about sharks in our sea (Sea of Japan) before everybody started to go for fishing on their new motor boats.


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - peter - 11-24-2018

(11-07-2018, 08:05 PM)epaiva Wrote:
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B

A - ON THE FIRST MAIL (see above) OF MS. OLGA KRASNYKH, OWNER OF THE BOHAI TOUR AGENCY

In order to find out a bit more about tigers and brown bears in the Russian Far East, Epaiva contacted someone in the know in Russia. Good initiative, Epaiva! Ms. Olga Krahnykh, owner of the Bohay Tour Agency, decided to respond. Many thanks, Olga Krasnykh!

Two of her ideas (tigers and noses and tigers expelling brown bears), resulted in a few frowns.

Noses (a1) first. Those who read Jim Corbett's books know he wrote about noses as well. Males in particular do not like to be struck on the nose, he said. Could be related to smelling and could be related to something else. The trainers I interviewed confirmed that adult male tigers, lions and bears, and tigers in particular, are quite sensitive regarding their nose.   

Tigers expelling brown bears (a2). Those interested in Amur tigers and Ussuri brown bears know that adult males of both species avoid serious problems. In the article recently discussed in this thread, researchers again concluded that male tigers do not hunt adult male bears. They also didn't find solid evidence of male brown bears displacing male tigers. Not in the period 1992-2013, that is. I know of a number of exceptions, but this seems to be the general rule.

In adult females, the situation is more complicated. Male brown bears, and the occasional large male Himalayan black bear, rob tigresses at times. They also 'share' meals with tigresses. Tigresses followed by male brown bears at times attack them in order to defend their cubs. Tigresses have been killed, but incidents of that nature are few and far between. 

More often than the other way round, tigers attack bears. Although Bromlej saw a quite large, but youngish brown bear (estimated at about 170 kg.) killed and eaten by a tigress, adult male tigers in particular hunt brown bears. Although most target immature brown bears, adult females are hunted as well. Doesn't happen often, but it's not very rare. In the article recently discussed in this thread (see above), researchers found 2 immature and 5 adult female brown bears killed by male tigers.

In the north- (close to Chabarowsk) and southwest (close to China), bears are hunted more often. In some seasons, they are as important as deer and wild boars. Time to find out a bit more about tigers hunting bears.

B - THE BOL'SHEKHEKTIRSKII RESERVE AND ITS ENVIRONS (K.N. Tkatchenko)

Here's an abstract I made some years ago. It's entirely based on 'Specific features of feeding of the Amur tiger (Panthera tigris altaica (Carnivora, Felidae) in a densely populated locality (with reference to Bol'shekhektirskii Reserve and its environs', that was published in 2012.  


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C - FOOD HABITS OF AMUR TIGERS AT THREE SITES IN THE RUSSIAN FAR EAST

Here's a few scans of 'A comparison of food habits and prey preference of Amur tiger (Panthera tigris altaica, Temminck, 1884) at three sites in the Russian Far East', that was discussed more than once:


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D - THE SICHOTE-ALIN RESERVE AND ITS NEIGHBOURHOODS

Here's two scans of the article on the interspecific relationships between amur tigers and brown and Himalayan black bears that was recently discussed in this thread: 


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E - BART SCHLEYER

Bart Schleyer was involved in the Siberian Tiger Project (STP) some time ago. Most unfortunately, he died well before his time. This orbituary was posted some years ago (this thread). In order to keep the length of the post limited, I decided for scans of the first and last page:


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F - CONCLUSIONS

The Russian Far East is the only region where Amur tigers (Panthera tigris altaica), Himalayan black bears (Ursus thibetanus) and brown bears (Ursus arctos lasiotus) co-exist. It's the only region where tigers habitually hunt bears.

Research says that bears are an important food item for tigers, especially in summer. In some regions and seasons, bears are as important as deer and wild boars.  

Today, there about 550-600 wild Amur tigers and at least 10 000 brown bears in the Russian Far East. Although the effect of predation on the brown bear population is limited, the number of adult female brown bears killed by tigers is relatively high in some parts of the Russian Far East. 

Brown bears are hunted by adult male tigers in particular. Research suggests that some male tigers develop into bear specialists. The tiger known as 'Dale' was one, but it's likely there are more. As specialists most probably target quite large bears (up to 150-200 kg. according to researchers), one has to assume that brown bears will respond over time.

Is it, as Ms. Olga Krasnykh suggested, likely that tigers 'expelled' brown bears in some districts or regions? According to the scientists working in the Leopard Land National Park, it is. This is a quote from the last post of Ms. Krasnykh in the thread 'Bear and big cat interactions in the wild':

" ... I have interesting info for you. Yesterday I had a dinner with the scientists from Leopard Land National Park and asked them a question about tigers and bears. And I was very surprised that they agree with my assumption that tigers expelled brown bears ... " (post 177 in the thread 'Bear and big cat interactions in the wild').

" ... Tigers kill a lot of brown bear cubs, that's why their population is much less than in Kamchatka and other Russian regions. That's what our scientists say ... " (post 177).

Is this new information? Yes.

One respected member of this forum overdid it somewhat when he said Ms. Krasnykh was a bit 'sloppy' regarding the tigers-expel-bears remark. A bit disappointing, I thought. On a public forum, good debates are vital. Debates are about the free exchange of information and ideas. One of the fundamentals of the debate is mutual respect. At all times. Was Ms. Olga Krasnykh 'sloppy'? Far from it.

G - TO CONCLUDE 

g1 - Male tigers and female brown bears

According to Bart Schleyer, all bears attacked by tigers were killed. All were killed with a bite to the base of the skull, severing the spine. Based on 'visual evidence', Russian researchers estimated that the largest females ranged between 150-200 kg. (330-441 pounds). In two cases, the fight was prolonged.

I never saw a skull of a wild male Amur tiger, but I did measure quite a few skulls of captive adult males. I also saw a number of brown bear skull from Canada, including those of adult females. Would an adult male Amur tiger be able to quickly kill an adult female brown bear with a bite to the base of the skull? Based on what I saw, the answer is affirmative.

Here's a photograph showing the skull of what must have been a large male liger and a large female brown bear. According to the one who posted the photograph, the sow was 800 pounds:


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Skulls of adult male brown bears are larger than skulls of adult female brown bears. This skull (Romania, 1935) had a greatest total length of 393 mm. and a zygomatic width of 247 mm. (weight 2,284 kg.). The skull is in the Hungarian Natural History Museum:  


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g2 - Amur tiger, female brown bear and cub

Found this on the internet some time ago. Nice drawing: 


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g3 - Did the new info provided by Ms. Olga Krasnykh change my opinion on tigers and brown bears in the Russian Far East?

In a way. It was known that male Amur tigers hunt brown bears up to the size of adult females. It's not surprising that female brown bears with cubs would respond. Leaving a district with a bear specialist seems a good decision when you have cubs.  

I would be interested in more information about the relationship between adult males of both species. Could be a bit different than many assume. Researchers also seem to think so: a number of them adjusted their opinion on tigers and bears over the years.

For now, we have to make do with the opinions of naturalists, biologists, rangers and locals. Not bad at all, but in the end we need reliable documents.  

Ms. Olga Krasnykh no doubt is in the know on tigers and bears. Furthermore, she has to opportunity to talk to others living close to tigers and bears all the time. We're very interested in what she has to say. Thanks again for the info, Ms. Krasnykh. Keep it coming.


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - brotherbear - 11-24-2018

Peter says: And sorry about the length of the post. I know it has a lot of info posted before, but I felt it was needed to get to a kind of conclusion. In the next posts, I will focus on the size of Amur tigers a century ago and today. In between, the Sungari river tiger will be discussed one more time. This time, I'll add info from V. Jankowski himself.
 
Length of the post not a problem. We all know that you favor the tiger and me the brown bear. But what we have in common is the fact that we both want the truth; the accurate facts. Today, I learned more.  I had assumed that when a tiger ambushed a bear weighing upwards to 440 pounds, it was a miscalculation by the tiger. Evidently not so. Also, that a tiger can kill a bear of this size with a single well-placed bite. Interested in learning more. Not about winning -  about knowing. 
Oh, about noses, a bear is very aware of protecting his nose in any skirmish. Very sensitive. 


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - paul cooper - 11-26-2018

Yea yea guys, just make sure to stick with the left one.


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RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - peter - 11-27-2018

(11-24-2018, 04:54 PM)brotherbear Wrote: Peter says: And sorry about the length of the post. I know it has a lot of info posted before, but I felt it was needed to get to a kind of conclusion. In the next posts, I will focus on the size of Amur tigers a century ago and today. In between, the Sungari river tiger will be discussed one more time. This time, I'll add info from V. Jankowski himself.
 
Length of the post not a problem. We all know that you favor the tiger and me the brown bear. But what we have in common is the fact that we both want the truth; the accurate facts. Today, I learned more.  I had assumed that when a tiger ambushed a bear weighing upwards to 440 pounds, it was a miscalculation by the tiger. Evidently not so. Also, that a tiger can kill a bear of this size with a single well-placed bite. Interested in learning more. Not about winning -  about knowing. 
Oh, about noses, a bear is very aware of protecting his nose in any skirmish. Very sensitive. 

Point taken, my friend. Preference always is a factor to consider. The only way to oppose it is to focus on reliable and accurate information. This post is an attempt to get to a bit more accuracy on the observation of researchers regarding the size of the largest female brown bears killed by tigers in the Russian Far East.

1 - THE AVERAGE SIZE OF ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST
 
Recent research says that experienced, often older (referring to Schleyer's observation - see my previous post), male Amur tigers hunt brown bears up to the size of an adult female. Anything known on the size of adult female brown bears in the Russian Far East?

This table (from a recently published document) was posted by Guate a week ago. It says that adult female brown bears today average 145 kg. (321 pounds):


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2 - INDIVIDUAL VARIATION IN ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST

A decade ago or so, I saw a table with weights of adult male and female brown bears in the Russian Far East. Adult male brown bears averaged 264 kg. (about 580 pounds), whereas adult female brown bears averaged 189 kg. (420 pounds). Compared to the table above, the average of adult males is a bit lower, whereas female brown bears are almost 100 pounds heavier. How explain? 

The table above, regarding the average weight of brown bears, is based on recent research of biologists, whereas the other table could have been based on bears shot by trophy hunters. As trophy hunters tend to select the largest individuals, tables based on their records should be taken with some care. 

The Russian Far East has many thousands brown bears. If we add that individual variation is pronounced in large mammals like brown bears, one never quite knows what to make of averages. Based on what was published, however, I do not doubt that a large female brown bear can severely outweight an average adult male Amur tiger.

In AVA, a Chinese poster with access to good information (KTKC, if I remember correctly) said female brown bears well exceeding 700 pounds had been shot not so long ago in the northeastern part of China. I've also seen reliable reports about exceptional females shot in the Russian Far East. Poster WaveRiders recently said he has seen skulls of very large female brown bears.

3 - KERLEY 

In 2011, Linda Kerley was contacted by a poster called 'Junglesprout' from AVA about brown bears and tigers. Her answer, posted on September 12, 2011, was printed. Unfortunately, the quality of the print was well below par. For this reason, I decided for a few quotes:

" ... I have been studying tiger food habits for the past 14 years and have found several bears killed and eaten by tigers. Some tigers specialize in eating bears and they will (part of the sentence is missing) ... larger brown bears. We radio-tracked one male tiger who ate bears all summer and lost weight in the winter presumably because he couldn't find his favorite food ... " (post of Junglesprout of September 12, 2011).

" ... Bears are an important food source for tigers in summer ... " (do.).

" ... I have seen tigers prey on all shapes and sizes of black bears and up to the largest and healthiest female brown bear ... " (do.).

" ... what we know is there are no rules - anything can happen between bears and tigers ... " (do.). 

4 - BAIKOV

In 1925, 'The Manchurian tiger' was published. About 75 years later, it was translated into English by Alex Shevlakov. I have the translation. It's an interesting document written by a man who hunted tigers himself.  

In the days of Baikov, Amur tigers ranged between the central part of what's now South-Korea to the northwestern part of Manchuria. Back then, Amur tigers were larger and heavier than today. In Baikov's opinion'('The Manchurian Tiger', 1925, pp. 4), males " ... quite often ... " got to " ... 20 poods ... " (about 320 kg. or 706 pounds). The measurements of a full-grown male given on page 9 are exceptional. In his opinion, " ... the muscular system of the body is extremely massive and perfectly developed ... " (do., pp. 9).

Although most of the weights he mentioned were qualified as 'unreliable', some were accepted in an evaluation of old records published a decade ago. Based on records regarded as 'highly reliable', it was concluded that adult male Amur tigers could have averaged 210-220 kg. (460-481 pounds) about a century ago. The 'historical' average of adult females was 137,5 kg. (303 pounds).

I'm not too sure about the outcome of the evaluation. Apart from the 560-pound male shot by Baikov near the Korean border in 1911, all records of tigers exceeding 550 pounds were classified as 'unreliable'. This although experienced hunters like Baikov and Jankowski agreed that large individuals well exceeded 600 pounds in their day. Tigers exceeding that mark have also been shot in the 20th century.

In 1943, a very large tiger was shot by a member of V. Jankowski's team near the Sungari river. In his letter to V. Mazak in May 1970, V. Jankowski wrote the tiger was at least 300 kg. In his book 'Tiger, deer and ginseng', published in 1993, V. Jankowski said the tiger was 350 kg. (772 pounds). In spite of the photograph published by V. Mazak, those evaluating old records ignored the report.

The photograph, by the way, showed a robust and large-skulled tiger that could have compared to the Duisburg zoo tiger. The Duisburg zoo tiger was 320 cm. in total length in a straight line (head length 50 cm.) and estimated at 280-300 kg. in his prime. V. Jankowski said the tiger shot in 1943 was the largest he saw by a margin. About as large as they get, he thought.       

Baikov wrote that Amur tigers had been pushed out of most of Korea and the southwestern part of Sichote-Alin. The home range of the Manchurian tiger was Guiring Province in northeastern China, where it was often seen in the

" ... extensive primeval woods of the upper Sungari, the Lalinkhe and Ashikhe, and also following river basins: the Mudan-jan, Muren and Sui-foung. Some points in this forested area which has a Chinese name Shu-Kai (the wood sea), have names which are relative to the tiger, for example, the Tiger Mountains, the Tiger lowlands, the Tiger ravines, and so on. Even now (1925), this area is covered with almost continuous virgin forest, although significantly thinned recently on the borders and on the KVZhD (Chinese Eastern Railroad), but 25 years ago it was actually a continuous green sea of impassable primeval Woods, where every animal lived at ease, and where the tiger alone reigned ... " (do., pp. 6).

As to tigers hunting bears:

" ... A rather big tiger would defeat a bear of almost the same weight. For this purpose, the predator tracks down the bear and makes an ambush, ordinarily on a rock or in windfallen trees, taking the side against the wind. Carelessy a bear slowly goes by an ambush, suspecting nothing, and the tiger rushes out on it from above, its one paw claws under the bear's chin, the other paw at the throat, and the tiger bites through the neck vertebrae ... " (do., pp. 14).

5 - IMMATURE MALE BROWN BEARS

According to the table above, two-year old male brown bears average 169 kg. (374 pounds). Significantly heavier than an average adult female brown bear, that is. In spite of their weight, male brown bears of that age are no match for an adult male Amur tiger. The reason is that tigers are experienced hunters, whereas brown bears of that age are not.

Any cases known of immature male bears killed by tigers?

Tiger 'Boris', also known as 'Putin's tiger', was partly raised in a rehabilitation facility. When he was released, researchers were able to follow him. At a relatively young age, Boris killed 2 brown bears. It wasn't possible to determine the gender of the bears, but researchers concluded that both were immature (2-4 years of age).

In the article about interspecific relations between tigers and bears recently discussed in this thread, researchers said they found a male brown bear in his third or fourth year. The bear had been killed by a tiger. Assuming that the bear was about average in size, it's likely he was about as heavy as his killer, if not heavier.

In early May 1951, a brown bear was killed and partly eaten by an adult tigress (Bromlej, 1965). V. Mazak ('Der Tiger', 1983) said the bear had been an adult male, but the length (158 cm.) and weight of the bear (approximately 170 kg. or 375 pounds) point towards an immature male or an adult female. 

Here's a photograph of the bear killed in May 1951 ('Der Tiger', V. Mazak, 1983, pp. 91):


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6 - WEIGHT ESTIMATES BASED ON SIGHT: THE DIFFERENCE BETWEEN PROFESSIONALS AND AMATEURS

Researchers think that the heaviest adult female brown bears killed by male Amur tigers ranged between 150-200 kg. (330-441 pounds). As far as I know, not one of the bears was measured and weighed. The estimates were based on sight, that is.

Warsaw said that estimates based on sight can result in significant exaggerations. I agree, but not to the degree he suggested.  

In the days I often visited a big cat facility in the northern part of the Netherlands, I did a few experiments. In one of them, I asked a number of visitors to estimate the length and weight of 4 adult captive big cats (1 adult male lion and 3 adult male Amur tigers). The distance between the visitors and the cats, before they were drugged, was 2-4 m. (7-13 feet roughly). Their estimates were recorded and the experiment was repeated more than once. To keep it short: not one of them got close. 

Most visitors overestimated cats with (relatively) big skulls and underestimated big cats with (relatively) smaller skulls (and stripes). Any difference between amateurs and those with experience? Yes. Significant? Yes. Amateurs are nearly always way off, whereas professionals usually are quite close. Within professionals, experience is important. A keeper or vet who has weighed big cats very often is quite a bit closer than a pro without experience.    

Adult brown bears have relatively large skulls, meaning it's likely that they could be overestimated. It's, however, also likely that the rangers and biologists who saw them had some experience.  

CONCLUSIONS

1 - Today, adult female brown bears in the Russian Far East average 145 kg. (321 pounds).

2 - Individual variation in adult female brown bears is pronounced. Whereas some barely exceed 200 pounds, others well exceed 700.

3 - According to Kerley, experienced male Amur tigers hunt brown bears up to the the size of the healthiest and largest female.

4 - According to Baikov, a " ... rather big tiger would defeat a bear of almost the same weight ... " ('The Manchurian Tiger', 1925, pp. 14).

5 - Adolescent male brown bears, ranging between 2-4 years of age, have been killed by tigers. Two-year old male brown bears, averaging 169 kg. (374 pounds), are significantly heavier than adult female brown bears.

6 - Amateurs often overestimate the weight of captive big-skulled mammals like brown bears. Professionals, however, often are quite close. Within this group, there's a significant different between those who have measured and weighed animals and those who have not. 

7 - All in all, I'd say that it's more than likely that the estimates of experts regarding the weight of adult female brown bears killed by tigers (150-200 kg. or 330-441 pounds) could have been quite accurate. Furthermore, it's known that experienced tigers have killed brown bears ranging between 150-200 kg.


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - Shadow - 11-28-2018

(11-27-2018, 11:35 PM)peter Wrote:
(11-24-2018, 04:54 PM)brotherbear Wrote: Peter says: And sorry about the length of the post. I know it has a lot of info posted before, but I felt it was needed to get to a kind of conclusion. In the next posts, I will focus on the size of Amur tigers a century ago and today. In between, the Sungari river tiger will be discussed one more time. This time, I'll add info from V. Jankowski himself.
 
Length of the post not a problem. We all know that you favor the tiger and me the brown bear. But what we have in common is the fact that we both want the truth; the accurate facts. Today, I learned more.  I had assumed that when a tiger ambushed a bear weighing upwards to 440 pounds, it was a miscalculation by the tiger. Evidently not so. Also, that a tiger can kill a bear of this size with a single well-placed bite. Interested in learning more. Not about winning -  about knowing. 
Oh, about noses, a bear is very aware of protecting his nose in any skirmish. Very sensitive. 

Point taken, my friend. Preference always is a factor to consider. The only way to oppose it is to focus on reliable and accurate information. This post is an attempt to get to a bit more accuracy on the observation of researchers regarding the size of the largest female brown bears killed by tigers in the Russian Far East.

1 - THE AVERAGE SIZE OF ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST
 
Recent research says that experienced, often older (referring to Schleyer's observation - see my previous post), male Amur tigers hunt brown bears up to the size of an adult female. Anything known on the size of adult female brown bears in the Russian Far East?

This table (from a recently published document) was posted by Guate a week ago. It says that adult female brown bears today average 145 kg. (321 pounds):


*This image is copyright of its original author
 
2 - INDIVIDUAL VARIATION IN ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST

A decade ago or so, I saw a table with weights of adult male and female brown bears in the Russian Far East. Adult male brown bears averaged 264 kg. (about 580 pounds), whereas adult female brown bears averaged 189 kg. (420 pounds). Compared to the table above, the main difference is the average of adult female brown bears. How explain?

The table above, regarding the average weight of brown bears, is based on recent research of biologists. Their info hasn't been published. The table in which adult female brown bears averaged 189 kg., however, could have been based on bears shot by trophy hunters. As trophy hunters tend to select the largest individuals, tables based on their records should be taken with some care. 

The Russian Far East has many thousands brown bears. If we add that individual variation is pronounced in large mammals like brown bears, one never quite knows what to make of averages. Based on what was published, however, I do not doubt that a large female brown bear can severely outweight an average adult male Amur tiger.

In AVA, a Chinese poster with access to good information (KTKC, if I remember correctly) said female brown bears well exceeding 700 pounds had been shot not so long ago in the northeastern part of China. I've also seen reliable reports about exceptional females shot in the Russian Far East. Poster WaveRiders recently said he has seen skulls of very large female brown bears.

3 - KERLEY 

In 2011, Linda Kerley was contacted by a poster called 'Junglesprout' from AVA about brown bears and tigers. She responded. Her answer, posted on September 12, 2011, was printed, but the quality of the print was well below par. For this reason, I decided for a few quotes:

" ... I have been studying tiger food habits for the past 14 years and have found several bears killed and eaten by tigers. Some tigers specialize in eating bears and they will (part of the sentence is missing) ... larger brown bears. We radio-tracked one male tiger who ate bears all summer and lost weight in the winter presumably because he couldn't find his favorite food ... " (post of poster 'Junglesprout' of September 12, 2011).

" ... Bears are an important food source for tigers in summer ... " (do.).

" ... I have seen tigers prey on all shapes and sizes of black bears and up to the largest and healthiest female brown bear ... " (do.).

" ... what we know is there are no rules - anything can happen between bears and tigers ... " (do.). 

4 - BAIKOV

In 1925, 'The Manchurian tiger' was published. About 75 years later, it was translated into English by Alex Shevlakov. I have the translation. It's an interesting document written by a man who hunted tigers himself. On foot, that is. 

In the days of Baikov, Amur tigers ranged between the central part of what's now South-Korea to the northwestern part of Manchuria. Back then, Amur tigers were larger and heavier than today. In Baikov's opinion, the Manchurian tiger " ... quite often ... " (The Manchurian tiger, pp. 4) weighed " ... 20 poods ... " (about 320 kg. or 706 pounds). The measurements of a full-grown male given on page 9 are exceptional.  In his opinion, " ... the muscular system of the body is extremely massive and perfectly developed ... " (do., pp. 9).

Although some of the weights Baikov mentioned in 'The Manchurian Tiger' were qualified as 'unreliable', others were accepted in an overview of old records published a decade ago. Based on records regarded as 'highly reliable', it was concluded that adult male Amur tigers could have averaged 210-220 kg. (460-481 pounds), whereas adult females averaged 137,5 kg. (303 pounds).

I'm not too sure about the outcome of the survey, as the tiger shot near the Sungari river in 1943 by a member of V. Jankowski's team was exceptionally robust as well. In his letter to V. Mazak in May 1970, V. Jankowski wrote the tiger was at least 300 kg. In his book 'Tiger, deer and ginseng', published in 1993, he said the tiger was 350 kg. (772 pounds). The photograph published by V. Mazak showed a very robust male tiger.

According to Baikov, Amur tigers had been pushed out of most of Korea and the southwestern part of Sichote-Alin. The home range of the Manchurian tiger was Guiring Province in northeastern China, where it was seen often in the

" ... extensive primeval woods of the upper Sungari, the Lalinkhe and Ashikhe, and also following river basins: the Mudan-jan, Muren and Sui-foung. Some points in this forested area which has a Chinese name Shu-Kai (the wood sea), have names which are relative to the tiger, for example, the Tiger Mountains, the Tiger lowlands, the Tiger ravines, and so on. Even now (1925), this area is covered with almost continuous virgin forest, although significantly thinned recently on the borders and on the KVZhD (Chinese Eastern Railroad), but 25 years ago it was actually a continuous green sea of impassable primeval Woods, where every animal lived at ease, and where the tiger alone reigned ... " (do., pp. 6).

As to tigers hunting bears:

" ... A rather big tiger would defeat a bear of almost the same weight. For this purpose, the predator tracks down the bear and makes an ambush, ordinarily on a rock or in windfallen trees, taking the side against the wind. Carelessy a bear slowly goes by an ambush, suspecting nothing, and the tiger rushes out on it from above, its one paw claws under the bear's chin, the other paw at the throat, and the tiger bites through the neck vertebrae ... " (do., pp. 14).

5 - THE WEIGHT OF ADOLESCENT MALE BROWN BEARS

Immature and adolescent male brown bears can be as heavy as an average adult female brown bear, if not considerably heavier: the table above says that 2-year old male brown bears average 169 kg. (374 pounds). Male brown bears of that age, in spite of their weight, are no match for an adult male Amur tiger. The reason is they are no experienced professional predators.

Any cases known of adolescent male bears killed by tigers?

Tiger 'Boris', also known as 'Putin's tiger, was raised in a rehabilitation facility. When he was released, he was collared. This means that researchers were able to follow him. When still immature, Boris fought and killed 2 brown bears. It wasn't possible to determine the gender of the bears, but both were adolescents ranging between 2-4 years of age.

In the article about interspecific relations between tigers and bears recently discussed in this thread, researchers said they found a male brown bear in his third or fourth year killed by a tiger. Assuming he was about average in size, it's likely that he was as heavy as his killer, if not heavier.

Bromlej mentioned a brown bear killed by an adult tigress near the Tatibe river in early May 1951. The bear was 158 cm. in length and estimated to have weighed about 170 kg. Although he didn't say anything about it, there have been many debates about the gender. V. Mazak (1983) also referred to the incident. He said the brown bear had been an adult male, but quite a few posters doubt his conclusion. 

6 - WEIGHT ESTIMATES BASED ON SIGHT: THE DIFFERENCE BETWEEN PROFESSIONALS AND AMATEURS

Researchers think that the heaviest adult female brown bears killed by male Amur tigers ranged between 150-200 kg. (330-441 pounds). As far as I know, the bears were not weighed and measured. The estimates were based on sight.

Warsaw said that estimates based on sight can result in significant exaggerations. I agree. But. 

In the days I quite often visited a big cat facility in the northern part of the Netherlands, I did a few experiments. Before I measured and weighed 4 captive big cats (1 adult male lion and 3 adult male Amur tigers), I asked a number of visitors to estimate the length and weight of the big cats they saw. The distance between the visitors and the cats, before they were drugged, was 2-4 m. (6-13 feet). Their estimates were recorded. To keep it short: not one of them even got close. The experiment was repeated more than once.

The conclusion is that people tend to overestimate cats with big skulls and underestimate big cats with stripes. By a margin, I have to add. Any difference between amateurs and those with experience? Yes. Significant? Yes. Amateurs are nearly always way off, whereas professionals usually are quite close. Within professionals, experience is important. Someone who has weighed big cats and bears very often is much closer than a pro without experience.    

Adult brown bears, males and females, have relatively large skulls, meaning it's likely that they could be overestimated. As we're talking about wild brown bears, it's very likely that the distance between the observers and the bears would have been significant. It's, however, also very likely that those involved had experience. This, I noticed in captive big cats and bears, is important.

CONCLUSIONS

1 - Adult female brown bears in the Russian Far East average 145 kg. (321 pounds).

2 - Individual variation in adult female brown bears in the Russian Far East is pronounced. Whereas some barely exceed 200 pound pounds, others exceed 700.

3 - According to Kerley, experienced male Amur tigers hunt brown bears up to the the size of the healthiest and largest female.

4 - According to Baikov, a " ... rather big tiger would defeat a bear of almost the same weight ... " ('The Manchurian Tiger', 1925, pp. 14).

5 - Adolescent male brown bears, ranging between 2-4 years of age, have been killed by tigers. Recent information says that two year old male brown bears, averaging 169 kg. (374 pounds), are significantly heavier than adult female brown bears.

6 - It's likely that weight estimates of big-skulled mammals (like brown bears) seen from a distance will result in significant exaggerations. There is, however, a significant difference between amateurs and professionals. Within professionals, there's a significant different between those with experience and those without.

7 - All in all, I'd say that it's more than likely that the estimates of experts regarding the weight of adult female brown bears killed by tigers (150-200 kg. or 330-441 pounds) could have been quite accurate. Furthermore, it's known that experienced tigers have killed brown bears ranging between 150-200 kg.

If someone some day would find statistics about bears so, that there would be explained, what is meant by adult in that statistic. It would be interesting to see statistics about bears so, that not too much open questions.

Then also would be interesting to see statistics about bears, which are full grown. That means bears 9-11 years old. Because bears grow size for so long time, there can be many opinions and points of views how to look at statistics. Maybe it would be pretty fair to talk about adult bears, when those are about 5-6 years old even though not full grown yet (?). But of course if talking about adult tigers only when those are old enough to be full sized (not weight), then of course same should be with bears. But does someone have that kind of statistic information is another question :)


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - brotherbear - 11-28-2018

Quote: 6 - Amateurs often overestimate the weight of captive big-skulled mammals like brown bears. Professionals, however, often are quite close. Within this group, there's a significant different between those who have measured and weighed animals and those who have not.  
 
Amateurs will nearly always, I would say probably at least 98% of the time, greatly over estimate the weight of a bear. Even hunters. But biologists are very good at making very close estimations. They have to develope this skill to near-perfect accuracy to dart bears with drugs. The life of the bear as well as the safety of the biologists depend on this skill. 


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - GuateGojira - 11-29-2018

(11-27-2018, 11:35 PM)peter Wrote: 1 - THE AVERAGE SIZE OF ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST
 
Recent research says that experienced, often older (referring to Schleyer's observation - see my previous post), male Amur tigers hunt brown bears up to the size of an adult female. Anything known on the size of adult female brown bears in the Russian Far East?

This table (from a recently published document) was posted by Guate a week ago. It says that adult female brown bears today average 145 kg. (321 pounds):


*This image is copyright of its original author

*This image is copyright of its original author 
2 - INDIVIDUAL VARIATION IN ADULT FEMALE BROWN BEARS IN THE RUSSIAN FAR EAST

A decade ago or so, I saw a table with weights of adult male and female brown bears in the Russian Far East. Adult male brown bears averaged 264 kg. (about 580 pounds), whereas adult female brown bears averaged 189 kg. (420 pounds). Compared to the table above, the average of adult males is a bit lower, whereas female brown bears are almost 100 pounds heavier. How explain? 

The table above, regarding the average weight of brown bears, is based on recent research of biologists, whereas the other table could have been based on bears shot by trophy hunters. As trophy hunters tend to select the largest individuals, tables based on their records should be taken with some care. 

The Russian Far East has many thousands brown bears. If we add that individual variation is pronounced in large mammals like brown bears, one never quite knows what to make of averages. Based on what was published, however, I do not doubt that a large female brown bear can severely outweight an average adult male Amur tiger.

In AVA, a Chinese poster with access to good information (KTKC, if I remember correctly) said female brown bears well exceeding 700 pounds had been shot not so long ago in the northeastern part of China. I've also seen reliable reports about exceptional females shot in the Russian Far East. Poster WaveRiders recently said he has seen skulls of very large female brown bears.

A few remarks:

About the table, this is from the document "Tooth breakage in tigers: cause for conflict?" published in 2012 by Dr Goodrich an others, and correspond to the chapter 11 from the monograph "Diseases and parasites of wildlife in Siberia and the Russian Far East".

Sadly the figures do not have the sample size and the range of the weights, but at least this give us an idea of the average weight of the large mammals from the Russia Far East. To make a comparison, the modern Amur tigers have an average weight of 190 kg for males and 120 for females.

Although full of incorrect ideas, insults and a huge grudge against tigers, sometimes to post of Warsaw have interesting information, for example this article: https://vladnews.ru/ev/vl/1360/53407/medvedi_batareykah

The article is in Russian, but with the help of Google translator, I got a good idea of what the article says. It seams that it was writen by Evgeny Suvorov, a journalist and author from Terney, Primorye region, and that had colaborated with scientists in scientific article.

The relevant part is this:

"Всего за восемь лет радиомаячки были надеты на шеи более четырех десятков медведей двух видов. Особенно активно косолапые стали попадаться в петли, когда ученые начали раскладывать возле ловушек пахучую приманку, к примеру, порченое мясо или рыбу. Правда, были отдельные умники, поедавшие всю приманку, но при этом умело обходившие все петли. Рекордсменами по весу оказались бурые самец - более 350 кг и самка - 222 кг. Среди гималайцев самым тяжелым оказался самец весом в 205 кг, а самочка - 101 кг. Есть у меченых медведей и рекордсмены по возрасту. Некоторым животным уже перевалило за 20 лет."

With Google translator:

"In just eight years, radio beacons were put on the necks of more than four dozen bears of two kinds. Clumsy dogs began to fall particularly actively into the loops when scientists began to lay out an odorous bait near the traps, for example, spoiled meat or fish. True, there were some clever men who ate the whole bait, but at the same time skillfully bypassed all the loops. The brown weight male was the record breaker by weight - more than 350 kg and the female - 222 kg. Among the Himalayans, the heaviest was a male weighing 205 kg, and a female — 101 kg. There are marked bears and champions by age. Some animals have already passed for 20 years."

Acording with these, more than four dozen (over 48?) bears has been captured, from both species, the heavies brown bear is of over 350 kg and the heaviest female is 222 kg. Now, lets compare them with the data reported by Dr Kucherenko colected in the decade of 1970:


*This image is copyright of its original author


It seems that the male bears are heavier in these days, but the females are lighter. The proposal of @peter (hunters normally select the largest specimens) seems reliable for females, but that will not explain why the male bears are heavier now. Other explanation will be that bears have a great fluctuation in its weights, so it will be necesary to know in what time of the year those bears were captured (specially the largest ones), and I suspect that the article of Mr Suvorov have the answer, but will I leave this part to others (too busy to investigate today).

I think that this information is going to be usefull for those that are participating in the debate of tiger-bear relationship, by the way, those bears are actually been weighed:

*This image is copyright of its original author


Greetings to all. Happy


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - brotherbear - 12-01-2018

GuateGojira says: It seems that the male bears are heavier in these days, but the females are lighter. The proposal of @peter (hunters normally select the largest specimens) seems reliable for females, but that will not explain why the male bears are heavier now. 
 
Just a thought; with less tigers there should be more wolves. If this is the case, then perhaps the bears are feeding well by scavenging wolf kills. 


RE: ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris) - GuateGojira - 12-02-2018

(12-01-2018, 10:23 PM)brotherbear Wrote: Just a thought; with less tigers there should be more wolves. If this is the case, then perhaps the bears are feeding well by scavenging wolf kills. 

Is a posibility, but we must remember that those bears are from the Sikhote Alin BZ, an area were wolves are rare thanks to tigers. I guess that maybe the high body mass is related with the inclution of large males and probably the season when they were captures. This is just a guess.