Follow-up of last post by Peter:
WOLVERINE
Many thanks for the link, the translation and the summary.
In the past years, Russian biologists more than once wrote that some large male bears deliberately follow and displace tigresses with cubs. The photographs and the article prove that they were right.
Satellite bears
Male brown bears following and displacing Amur tigresses with cubs, if correct, are known as 'satellite bears'. It seems that some of them do not hibernate. The most likely reason is they solved the food problem. At least, the tigresses they follow and displace did. And they will continue solving them as long as the pressure is kept up.
This means that the tigress targeted has to hunt for both her family and the hangman. As he often is at least twice, if not three times, her weight, the tigress has no option but to hunt large animals for an extended period of time. When she fails to deliver, chances are the male bear will target one of her cubs. Or all of them. If she protects her cubs, she could be severely wounded or killed. In both scenarios, her cubs could perish.
Encounters between 'satellite bears' and tigresses with cubs or young tigers
In Band III of 'Mammals of the Sovjet-Union' , a number of incidents between tigresses and 'satellite bears' were described:
" ... In a fight with a bear, the tiger isn't always victorious. In the 1959-1960 winter, a tigress with her two 2-year old cubs lived in a remote part of the Sichote-Alin Mountains. One day, she left them with a wild boar she had killed. When they were feeding, the tigress moved off. When she returned, she saw a large non-hibernating brown bear (also known as a 'Schatun') approaching the cubs and the wild boar. The tigress attacked the bear, but was killed in the fight that followed. In spite of his severe injuries, the 'Schatun' consumed both the wild boar and the tigress (Sysoev, 1960). In 1913, near the Great Sinantsch, a large brown bear killed a tiger. In 1960, in the Sichote-Alin Reserve, a young tiger was killed by a brown bear (V. Abramov, 1962). A similar incident happened in the Amur region (Krivopust, 1957) ... " ('Mammals of the Sovjet-Union', V.G. Heptner and A.A. Sludskij, German edition, Jena, 1980, pp. 150).
The first incident happened in winter, meaning the bear involved most probably was a non-hibernating bear or Schatun. As Schatuns and satellite-bears often are one and the same, it's possible that the bear had been following and displacing the tigress and her two cubs for some time. The last incident (referring to the incident quoted from Krivopusk) wasn't discussed by Heptner and Sludskij, but by V. Mazak:
" ... Kaplanov (1948) and Abramov (1962) agree that an adult brown bear can kill and eat young tigers left on their own by their mother. In 1956, in the Schuchti-Pokto Reserve near Chabarowsk, a 3-year old tiger was killed by a brown bear near the wild boar killed by his mother (Krivopusk 1957, ex Abramov 1962). Two similar incidents happened in the 1959-1960 winter and in the fall of 1960 when a tigress resp. a young tiger were killed by a brown bear (Abramov 1962, Heptner and Sludskij 1972) ... ('Der Tiger', V. Mazak, third edition, 1983, pp. 120).
This is a photograph of 2-year old Amur tiger killed and eaten by a brown bear (Mazak, 1983):
Based on these incidents and on recent observations of biologists, the conclusion is that tigresses with cubs are sometimes followed and displaced by large male brown bears. It's very likely that some of these bears also hunt young Amur tigers and tigresses in times of need (early spring and late autumn). More than one biologist wrote that male brown bears also hunt Himalayan black bears in this period of time.
Tigresses without cubs, on the other hand, can be dangerous for female brown bears. Kaplanov (in 'Der Tiger', V. Mazak, 1983, pp. 89), following a tigress in the Kolumbe River Basin, found the tigress had dug up and killed a female brown bear and her two cubs in February 1940. Similar cases have been described by V.K. Abramov ('Der Tiger', V. Mazak, 1983, pp. 89). Early May 1951, a bear with a body length of 158 cm. and about 170 kg. killed and eaten by an Amur tigress was found close to the Tatibe River ('Mammals of the Sovjet-Union', German edition, Jena, 1980, pp. 149).
Although the last incident proves that a tigress can kill a larger brown bear, one wouldn't fancy her chances in a fight with a large satellite-bear two or three times her weight. In order to give you an idea about the difference in size:
In early spring (just after hibernation) and late autumn (just before hibernation), bears need a lot of energy as fast as possible. Protein is the way to get there, but hunting isn't easy for bears. Cats, on the other hand, are natural hunters. When bears and cats co-exist, brown bears in particular often visit tiger kills. It's near these kill sites that tiger and bear most often meet and clash.
There are just over 500 Amur tigers and many thousands of bears in the Russian Far East. Nearly all bears, young or old, visit tiger kills. For Amur tigers, avoiding bears just isn't an option. They have to learn how to deal with bears and it starts when they are born. Cubs are protected by their mother, but when they disperse, at 18 months or a bit over, they are on their own.
Although there is no information about the period between adolescence and adulthood, it's very likely that many Amur tigers don't make it to adulthood. Those that do are, bearwise, true survivors. Not a few of them have learned to hunt bears. Although many posters seem to think that only male tigers hunt bears, there's plenty of evidence of Amur tigresses hunting bears or training their cubs in this respect.
Although an average captive Amur tigress is not much heavier than an average wild Amur tigress, some captive tigresses can exceed 160 kg. (353 pounds). One tigress shot because she had killed the owner of a (French) facility was just over 200 kg. (442 pounds). The heaviest wild Amur tigress I know of was 368 pounds (166,9 kg.), but it's likely that there were, or still are, heavier tigresses. The record tigress was shorter than average and also had a shortish skull.
Wild Amur tigresses today average about 120 kg. (265 pounds), maybe a bit more. The heaviest weighed in the last decades was below 130 kg. (287 pounds). The range in weight in wild Amur tigresses is quite limited, which is not typical for wild tigers. Could point towards a shortage of food or to a population bottleneck not too long ago. There have been several in the last century.
Sexual dimorphism in Amur tigers is outspoken. Captive males average about 215 kg. (474 pounds), but the range is remarkable. Small adult males are just over 160 kg. (353 pounds), whereas the heaviest top 300 kg. (662 pounds). A decade ago, wild male Amur tigers averaged about 177 kg. (390 pounds). As the historic average for wild males was about 215 kg. (474 pounds), it means that male Amur tigers, largely as a result of bad conditions and low numbers, lost about 80 pounds in a century.
However. The sample resulting in 177 kg. a decade ago included a number of 'problem tigers' as well as a few 3-4 year old animals. Dale Miquelle thought that adult males today average about 430 pounds (195 kg.), but Guate's table suggested that 185-190 kg. (410-420 pounds) could be closer to the mark. I propose to use 190 kg. (420 pounds) for now. Compared to a century ago, this means they lost about 50 pounds. As prey depletion still is a problem, Amur tigers today probably hunt bears more often than they did a century ago.
As the conditions in Russia have improved, the number of tigers has risen. As more tigers and better conditions should result in more individual variation, one would expect a 500-pound male Amur tiger sooner or later. A decade ago, Kretzschmar said he had seen tracks of very large male tigers. Although the heaviest male to date is a young adult just over 210 kg. (464 pounds), recent photographs suggest that Kretzschmar could be right. I have no information about this male, but he seems healthy and has a large skull. Surprise captured -
Although an average captive Amur tigress is not much heavier than an average wild Amur tigress, some captive tigresses can exceed 160 kg. (353 pounds). One tigress shot because she had killed the owner of a (French) facility was just over 200 kg. (442 pounds). The heaviest wild Amur tigress I know of was 368 pounds (166,9 kg.), but it's likely that there were, or still are, heavier tigresses. The record tigress was shorter than average and also had a shortish skull.
Wild Amur tigresses today average about 120 kg. (265 pounds), maybe a bit more. The heaviest weighed in the last decades was below 130 kg. (287 pounds). The range in weight in wild Amur tigresses is quite limited, which is not typical for wild tigers. Could point towards a shortage of food or to a population bottleneck not too long ago. There have been several in the last century.
Sexual dimorphism in Amur tigers is outspoken. Captive males average about 215 kg. (474 pounds), but the range is remarkable. Small adult males are just over 160 kg. (353 pounds), whereas the heaviest top 300 kg. (662 pounds). A decade ago, wild male Amur tigers averaged about 177 kg. (390 pounds). As the historic average for wild males was about 215 kg. (474 pounds), it means that male Amur tigers, largely as a result of bad conditions and low numbers, lost about 80 pounds in a century.
However. The sample resulting in 177 kg. a decade ago included a number of 'problem tigers' as well as a few 3-4 year old animals. Dale Miquelle thought that adult males today average about 430 pounds (195 kg.), but Guate's table suggested that 185-190 kg. (410-420 pounds) could be closer to the mark. I propose to use 190 kg. (420 pounds) for now. Compared to a century ago, this means they lost about 50 pounds. As prey depletion still is a problem, Amur tigers today probably hunt bears more often than they did a century ago.
As the conditions in Russia have improved, the number of tigers has risen. As more tigers and better conditions should result in more individual variation, one would expect a 500-pound male Amur tiger sooner or later. A decade ago, Kretzschmar said he had seen tracks of very large male tigers. Although the heaviest male to date is a young adult just over 210 kg. (464 pounds), recent photographs suggest that Kretzschmar could be right. I have no information about this male, but he seems healthy and has a large skull. Surprise captured -
A recent article on Amur tigers and brown bears strongly suggests that Amur tigers hunt bears more often than was assumed. In some regions and seasons (and summer in particular), bears are as important as wild boars and red deer. Some years ago, researchers wrote that largish bears would be too dangerous for Amur tigers, but Miquelle now thinks this assumption could have been incorrect.
Kamsjatka
In Kamsjatka, not that far away, some male brown bears hunt cubs up to 4 years of age in spring and summer. Charly Russell and his wife Maureen ('Grizzly Heart', Random House, 2002) lost one of the three orphaned cubs they rehabilitated to a cannabalistic male. He nearly got another one during a long chase (about 8 km.) partly witnessed by Russell. This male had killed two of the three cubs of a wild female before he attacked the Russell cubs.
*Note: Pictures on site at:
wildfact.com/forum/
