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Post by grrraaahhh on Sept 11, 2010 15:19:41 GMT -9
Abstract: Intraspecific predation of bears >1 year old is observed occasionally, but the mechanisms behind it are poorly understood and often debated. We documented 13 cases of intraspecific predation in brown bears (Ursus arctos) in 2 Scandinavian study areas during 668 bear-years of radiotracking 238 brown bears. We found area differences in the rates of intraspecific predation only for yearling females. Annual yearling female mortality due to intraspecific predation was higher (0.162, 6 of 38) in the south than in the north (no mortality recorded, 28 yearlings followed). No older subadult females were killed by other bears. Annual mortality rates due to intraspecific predation for males, areas combined, were: 0.032 for yearlings, 0.040 for 2-year-olds, and 0.061 for 3-year-olds, for a combined rate from age 1 through 3 years of 0.127. One adult female was killed. Staying with their mother did not significantly reduce intraspecific predation among yearlings. Neither population density, at the levels we observed, nor reduced food abundance influenced rates of intraspecific predation on yearlings in our areas. In our study areas, intraspecific predation on
yearling females was correlated positively with the number of adult males that had died 3 years previously and whether any adult male had died 2 years previously. In an earlier study, we found that cub mortality was elevated during the breeding season 2 years after the death of adult males. As we found a similar pattern for intraspecific predation on yearling females, we speculate that infanticidal males may be prone to kill subadult bears. Although based on a relatively small sample of mortalities, our results strengthen our earlier conclusion that the killing of adult males may have a population consequence that managers should consider.INTRASPECIFIC PREDATION IN SCANDINAVIAN BROWN BEARS OLDER THAN CUBS-OF-THE-YEARwww.bearproject.info/uploads/publications/A%2038%20Intraspecific%20predation%20in%20Scandinavian%20brown%20bear%20olde.PDF
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Post by grrraaahhh on Sept 11, 2010 15:35:36 GMT -9
VIDEO: Male grizzly bear kills grizzly cub
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Post by warsaw on Mar 2, 2011 9:44:48 GMT -9
Cannibalism in kamchatka brown bears(ursus arctos piscator)
"...В то же время избирательность весенней охоты в отношении самцов старшей возрастной группы способствовала "омоложению" популяции. Как известно, отдельные взрослые самцы медведей, и не обязательно крупные, специализируются на охоте на молодых медведей и медвежат, несмотря на наличие других источников белковой пищи. Избирательный многолетний промысел самцов в том же Елизовском районе привел к увеличению выживаемости медвежат. Молодые медведи после разрыва семейных связей ищут свои места обитания и нередко приходят в окрестности населенных пунктов. Чаще всего именно они становятся конфликтными..."
Some adult males (They're not necessarily large) specializes in killing subadults and cubs, despite the availability of protein from other sources.
Source:
On realishinsip between Brown Bear and Human in Kamchatka
V. N. Gordienko*, T. A. Gordienko
*Kamchatka Branch of Pacific Institute of Geography FED RAS, Petropavlovsk-Kamchatsky
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Post by warsaw on May 30, 2011 10:10:51 GMT -9
Brown bear in brown bear diet   B.S.Yudin,e d. Bear ecology.Nauka,Novosibirsk .Russia.( In Russian.)   "...During drought years in the eastern portions of Russia, low precipitation resulted in poor forage production and increased bear-human conflicts. When these conditions exist, bears in poor physical condition approach settlements and prey on livestock and humans.During 1962, one of the worst bear food years on record, 767 brown bears were shot in Tuva (south-central Siberia) and >200 died due to cannibalism by other bears. Wildlife officials estimated about 67% of the population was eliminated from this region in 1 year (Zyryanov and Smimov 1992). A similar situation was observed in 1984 in Magadan Oblast (north-eastern Russia) and in other regions of Russia (M.A. Krechmar, Institute of Biology of the North, Magadan, Russia, pers. commun., 1991). During these catastrophic food years, bear conflicts were not easily solved by removing nuisance bears because nearly all bears were involved in conflicts. Food availability conflicts in Russia were alleviated (partially) by providing an artificial food supply..." www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9_2_/Gillin_Chestin_Vol_9_2_.pdf |
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Post by grrraaahhh on May 30, 2011 15:45:39 GMT -9
Brown bear in brown bear diet B.S.Yudin,e d. Bear ecology.Nauka,Novosibirsk .Russia.( In Russian.) Thanks. |
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Post by warsaw on Dec 2, 2011 14:56:08 GMT -9
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Post by warsaw on Dec 11, 2011 11:43:19 GMT -9
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Post by warsaw on Jan 6, 2012 1:35:24 GMT -9
Brown bear in brown bear diet B.S.Yudin,e d. Bear ecology.Nauka,Novosibirsk .Russia.( In Russian.) Thanks. Here's a short explanation : "... During drought years in the eastern portions of Russia,
low precipitation resulted in poor forage production and
increased bear-human conflicts. When these conditions
exist, bears in poor physical condition approach settlements
and prey on livestock and humans.During 1962, one of the worst bear food years on record,
767 brown bears were shot in Tuva (south-central Siberia)
and >200 died due to cannibalism by other bears. Wildlife officials estimated about 67% of the population
was eliminated from this region in 1 year (Zyryanov and
Smimov 1992). A similar situation was observed in 1984
in Magadan Oblast (north-eastern Russia) and in other
regions of Russia (M.A. Krechmar, Institute of Biology
of the North, Magadan, Russia, pers. commun., 1991).During these catastrophic food years, bear conflicts were not easily solved by removing nuisance bears because nearly all bears were involved in conflicts. Food availability conflicts in Russia were alleviated (partially) by providing an artificial food supply..." www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_9_2_/Gillin_Chestin_Vol_9_2_.pdf |
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Post by warsaw on Feb 10, 2012 7:26:41 GMT -9
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Post by grrraaahhh on Feb 12, 2012 17:15:41 GMT -9
В то же время избирательность весенней охоты в отношении самцов старшей возрастной группы способствовала "омоложению " популяции . Как известно , отдельные взрослые самцы медведей, и не обязательно крупные, специализируются на охоте на молодых медведей и медвежат, несмотря на наличие других источников белковой пищи . Избирательный многолетний промысел самцов в том же Елизовском районе привел к увеличению выживаемости медвежат. Молодые медведи после разрыва семейных связе й ищут свои места обитания и нередко приходят в окрестности населенных пунктов . Чаще всего именно они становятся конфликтными . Thanks Warsaw. For people not familiar with Russian literature, biologists V. N. Gordienko & T. A. Gordienko provide some of the best data on Kamchatka brown bears. Bucking the popular image of the peaceful "healthy or high protein-diet fed" adult brown bear - he can also play the role of predator of bears. |
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Post by warsaw on Mar 13, 2012 12:54:07 GMT -9
 The mating system of the brown bear Ursus arctos Sam M. J. G. STEYAERT1,†, Anders ENDRESTØL2,†, Klaus HACKLÄNDER3, Jon E SWENSON4, Andreas ZEDROSSER5 |
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Post by warsaw on Mar 26, 2012 13:13:20 GMT -9
"...In addition to food availability, McLellan (1994) suggested
that intraspecific predation by males on females
and their cubs may be an important limiting factor for
grizzly bears. If true for the central Canadian Arctic, we
would expect sexual segregation in habitat use to be apparent
at one or both scales of habitat selection examined.
Our results support this prediction. Within the home
range, females with accompanying young did not exhibit
the same patterns of habitat selection throughout the summer,
late summer, and autumn as males and females without
accompanying young. Intraspecific predation by males
on females and their cubs in the Arctic has been documented
(Reynolds 1980; Nagy et al. 1983; Case and
Buckland 1998) and sexual segregation in habitat use may
be a strategy by females with cubs to avoid predatory
males (Ballard et al. 1993; Wielgus and Bunnell 1995a,b)..."
Philip D. McLoughlin · Ray L. Case · Robert J. Gau
H. Dean Cluff · Robert Mulders · François Messier
Hierarchical habitat selection by barren-ground grizzly bears
in the central Canadian Arctic
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Post by warsaw on Apr 28, 2012 9:58:53 GMT -9
The Life History of an Extraordinary
Female Barren-ground Grizzly Bear
Robert J. Gau
Wildlife and Fisheries Division
Department of Resources, Wildlife
and Economic Development
Government of the Northwest Territories
#600 5102-50th Avenue
Yellowknife, NT, X1A 3S8, Canada
"...Sometime in early 1995 a female
grizzly bear was born in a den with two
male siblings near the Lac de Gras area.
In May, one day after being introduced
to the world outside the confines of her
mother’s den, I captured all 4 bears. The
little female cub was tagged G608 and
her mother was fitted with a satellite/
VHF radio collar.
Over 1995 and 1996 I learned G608’s
mother, captured at 19 years of age, was
the matriarch of the area as her home
range encompassed at least 4 other
known females. G608 continued to grow
from her initial 6 kg weight and she
quickly developed while she vigorously
interacted with her male siblings. In
September 1996 I removed the collar
from G608’s mother..."
"...We captured G608 in the accompaniment
of an adult male each year
between 2000-2002. In 2003, at 8 years
old, I observed G608 just after den
emergence with 2 cubs-of-the-year on
May 16. However, at her May 19 capture
she had either lost or abandoned her
cubs. As with each other capture event,
she appeared in good physical condition
in 2003 and it was unknown why she
lost her cubs in the days prior to her
capture. The next scheduled visual
relocation of G608 was July 14, 2003. At
that time I found G608’s remains cached
in a style typical of a grizzly bear kill (the
earth was churned-up in the immediate
area) and grizzly bear scat with grizzly
bear fur was present. From the hourly
data pulled from her GPS collar, it
appeared something happened to her on
June 11 or 12 and the collar remained
stationary from June 13 onward. The kill
site was heavily willowed with a stream
running through the middle feeding a
small lake. The only thing left of her
carcass were small bones and many tufts
of fur. A piece of femur I found looked to
have a healthy amount of marrow in it.
The collar was found about 20 m from
the kill site, and a debris field of fur and
partial bones surrounded a 10 m area
around the kill site. A pile of recently
cleaned caribou bones were found also
within 30 m of the G608’s kill site. I can
only speculate that she may have been
killed while defending her caribou kill
against a larger bear, or perhaps she
attempted and failed to usurp another
bear’s kill..."
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Post by sarus on May 12, 2012 5:11:21 GMT -9
¨Infanticide and Cannibalism among Cantabrian Brown BearsDespite the difficulty of detecting and observing an adult bear killing a cub or juvenile, our records of at least nine confirmed cases between 1996 and 2010 highlight its importance. All those cases occurred during the breeding season between April and June, clearly supporting the theory that sexual motives are involved. Following one attack witnessed on April 27, we saw the female and the attacking male engaged in mating behaviour together 11 days later. When infanticide occurs, the aggressor attempts to kill all the cubs of the litter regardless of their sex. Of nine confirmed cases, seven resulted in the death of the entire litter (2 of three cubs, 2 litters of two, 2 of one and another of at least one). In a further case, one of two cubs survived the attack and in other case it was not possible to confirm if both died as the remains of only one were recovered and there were no further sightings of that group. One attack in June 2000 in the Natural Park of Fuentes del Narcea, Degaña and Ibias (Asturias), revealed how relentlessly and meticulously a male hunted down and killed the three cubs in the litter one by one despite the female’s fierce and desperate attempts to prevent it. Following up all the abovementioned attacks, we recovered the remains of eight cubs, seven of which had been partially eaten. Far from being exceptional behaviour, infanticide appears to be common in males in spring. Females with small cubs seem to a great extent to select habitat that allows them to avoid infanticide. Thus, females with cubs of the year can often be found on rugged rocky slopes –typical chamois habitat–, where their agile offspring can more easily escape an attack by a large male. Cub safety in their first months of life is as important as food availability. ================================================================= ================================================================= Libro Osas (segunda edición, ampliada y revisada).► www.fundacionosopardo.org/media/docs/Libro_Osas_2011.pdf================================================================= ================================================================= ¨
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Post by sarus on May 12, 2012 5:26:47 GMT -9
Infanticide and Cannibalism among Cantabrian Brown Bears Bear cub killed and eaten(?) by male brown bear. Bear cub killed and partially eaten by male brown bear. Bear cub killed and partially eaten by male brown bear.================================================================= ================================================================= Libro Osas (segunda edición, ampliada y revisada).► www.fundacionosopardo.org/media/docs/Libro_Osas_2011.pdf================================================================= ================================================================= ¨
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