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Post by warsaw on Feb 17, 2012 15:01:03 GMT -9
This is Othello, a relatively young, inexperienced bear, who wants to be the alpha male but may not have the strength or experience to carry it off. Note the scar, the result of a serious fight earlier in the day with George, his primary adversary. Note also that Othello is a brown bear (species) with black fur (color). One can't distinguish bear species by their fur color. There are black brown bears, and brown black bears, if you follow me. This is George. He's big. He's strong. But he's past his prime, and he might not prevail against Othello. George is also a nearly white brown bear, again showing that you can't distinguish bear species by fur color Othello succeeds in driving George off the beach ... temporarily.
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Post by warsaw on Mar 3, 2012 12:55:52 GMT -9
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Post by warsaw on Mar 13, 2012 12:51:42 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 19, 2012 12:37:19 GMT -9
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Post by warsaw on May 27, 2012 12:24:41 GMT -9
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Post by warsaw on Jun 6, 2012 13:01:15 GMT -9
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Post by Ursus arctos on Jun 18, 2012 12:00:14 GMT -9
Warsaw, I figured I'd post the info for my reply to the "short winded big cats" thread here: " Consistent with expectations under the hypothesis of male-driven evolution (Haldane 1947; Miyata et al. 1987), the overall average substitution rates of Y chromosome genes are the highest among nuclear genes (table 4 and supplementary fig. 8, Supplementary Material online) and observed other mammalian taxa such as primates (Huang et al. 1997; Makova and Li 2002), carnivores (Pecon-Slattery and O'Brien 1998), perissodactyls (Goetting-Minesky and Makova 2006), and rodents (Sandstedt and Tucker 2005). These results also demonstrate that the X-linked genes have the lowest and autosome genes intermediate rates of substitution (table 4 and supplementary fig. 8, Supplementary Material online). A notable exception to the expected rates of change with Y > X and Y > A occurs in evolution of the subfamily Ursinae (table 4 and fig. 4). Across the entire bear family, the ratio of Y/X = 1.933 (95% confidence interval [CI]: 1.262–2.605) (the equation: V(Y) = Y(1 − Y)/[L(1 − 4Y/3)2], V(X) = X(1 − X)/[L(1 − 4X/3)]2, V(Y/X) = V(Y)/E(X)2 + E(Y)2V(X)/E(X)4, and Y/X− = Y/X − 1.96s and Y/X+ = Y/X + 1.96s in accordance with Sandstedt and Tucker [2005]) and α = 3.624 (95% CI: 1.451–13.176) (the equation: Y/X = 3 α/(2 + α) shown in Miyata et al. [1987]) changes within Ursinae whereby Y/X = 1.313 (95% CI: 0.680–1.945) and α = 1.556 (95% CI: 0.587–3.687). Thus, possible male-driven evolution is highly supported in the deeper nodes of the phylogeny but not in the more recent Ursinae.
Low Divergence of Y Chromosome Genes within Ursinae
We explore 3 possible explanations for the discordant evolutionary rates observed with the Y chromosome in bear evolution (table 4 and fig. 4) namely, 1) biogeographical effects, 2) evolutionary characteristics of the Y chromosome, and 3) behavioral traits in the natural history of the subfamily Ursinae. Modern species of Ursinae evolved recently and rapidly during the Pliocene and Pleistocene (Yu et al. 2007) and likely experienced dramatic climatic changes linked with glaciations. For example, the brown bear (U. arctos) is distributed throughout North America, Europe, and Asia yet has unique phylogeographic patterns of extirpation and recolonization linked with patterns of glaciations (Hofreiter et al. 2004; Miller et al. 2006; Stoen et al. 2006). Stochastic changes brought about by population expansion, migration, and contraction during this time may have facilitated selective sweeps in the Y chromosome that led to less than expected substitution rates in Ursinae observed today. The effective population size of Y chromosome is smaller than autosomes (Lawson Handley and Perrin 2007). Therefore, if a favored mutation occurred on the Y chromosome in ancestral populations undergoing frequent structural changes, then the allele might spread more rapidly than expected. The replacement of a circulating Y chromosome with another within ancestral populations of Ursinae would result in the appearance of low levels of divergence between species observed here.
In contrast to the fixation of favorable mutations resulting in selective sweeps within a species, reduced genetic diversity on the Y chromosome is influenced also by the lack of conventional recombination during meiosis. A positive correlation exists between recombination rate and polymorphism within genomes (Innan and Stephan 2003). Consequently, due to the lack of recombination needed to remove harmful mutations, the fate of genes on the Y chromosome would depend on the inexorable accumulation of mutations (of which some will be deleterious), due to Muller's ratchet (Charlesworth B and Charlesworth D 1997). Advantageous mutations on the Y chromosome could cause the fixation of all deleterious mutations present on the chromosome, and successive “selective sweeps” of this kind would cause the fixation of deleterious alleles at many Y-linked loci (genetic hitchhiking). Background or purifying selection acting against these harmful mutations could reduce the number of Y chromosome variants within a species, leading to decreased diversity of the Y chromosome in a finite population.
As described above, the biogeographical effects experienced by ursine species combined with the nonrecombining characteristics of the Y chromosome could be the basis for low divergence of Y-linked genes in Ursinae. However, if these 2 factors alone regulate Y chromosome divergence, then other mammalian species within these same biogeographical regions should show similar patterns because these processes are not specific to bears. For example, the divergence of the 7 species within the domestic cat lineage and the 5 species of the leopard cat lineage of Felidae occurred roughly at the same time as Ursinae and within similar biogeographic zones (Johnson et al. 2006). However, these felid lineages do not show reduced diversity on the Y chromosome but instead are defined by unique diagnostic substitutions (Pecon-Slattery et al. 2004) correlated with increased rates of substitution relative to genes located on autosomes and the X chromosome (Johnson et al. 2006).
We propose that social behavior may be a significant factor in the discordant patterns of genome evolution in bears. The Ursinae, like most large mammals, exhibit male-biased dispersal and female philopatry (Matsuhashi et al. 1999; Nowak 1999; McLellan and Hovey 2001; Kojola et al. 2003; Onorato et al. 2004; Stoen et al. 2005, 2006). Migration caused by male-biased dispersal allows gene flow and is a potent force in homogenizing genetic divergence among subpopulations. In addition, the reproductive system of bears is polygynandrous by which a female may mate with 2 or more males, who themselves may pair with several different females (Nowak 1991). Therefore, if the social structure of female philopatry, male-biased dispersal, and polygynandry was present in ancestral populations of Ursinae, relatively low number of male breeders and high male migration rates would result in low effective population size and reduction of genetic diversity for the Y chromosome among breeding groups (Chesser and Baker 1996). Furthermore, female philopatry has been shown to increase the effective population size of mtDNA by one-half relative to autosomes and almost 6 times relative to the Y chromosome (Chesser and Baker 1996). Thus, genetic diversity of the Y chromosome among ancestral populations would be lost at a faster rate than mtDNA and autosomes. These results were also supported in Laporte and Charlesworth (2002) showing that under predominantly male migration, high genetic differentiation was obtained in mtDNA, followed by Y chromosome, X chromosome, and autosomes. In addition, Hoelzer (1997) and Hoelzer et al. (1998) showed that nodes within mitochondrial gene trees were deeper than those in nuclear gene trees if the female migration rate was low. Lastly, the effect of behavioral traits on the effective population size of autosomes may not be associated with differences in dispersal between sexes but rather male polygyny (Chesser and Baker 1996). Therefore, we suggest low divergence of Y-linked genes observed here compared with high divergence of mtDNA for the subfamily Ursinae (Yu et al. 2007) may be due, in part, to male migration, female philopatry, and polygynandry during ursine bear speciation. " Unequal Rates of Y Chromosome Gene Divergence during Speciation of the Family UrsidaeTo summarise: 1) More mutations take place in male germ cells than female germ cells. 2) Evidence for this is found in the fact that normally, when comparing related species, much higher mutation rates are evident in Y chromosomes (which spend 100% of their time in male bodies) than in autosomes (50% in each) or X chromosomes (2/3rds of time spent in females). 3) Evidence in the subfamily Ursinae is however very weak, due in part to a variety of factors-much of it held in common with other species that still demonstrate it suggesting differences are more extreme in subfamily Ursinae. Among these differences is a low number of male breeders. From Microsatellite Analysis of Paternity and Reproduction in Arctic Grizzly Bears: Info on total known males over 9 years old, and cubs they fathered (as well as ages of those males): Info on all known cubs, and who fathered them: Study lasted 6 years, and took place in Western Brooks Range, Alaska. Extremely low population density, and compared to other populations very undisturbed by humans. Heavily hunted and poached population in Sweden has much higher average reproductive success. No males under 9 years old reproduced. Only 1 male above 18 years old reproduced. Interesting that bear was probably way past his prime at 26-28 years old while reproducing, and fathered 10.53% of all cubs in the area-extremely impressive considering the presence of around 46 males over 9 years old in the area. I can only imagine he would have been even more prolific in his younger years! Only around half of 9+ year old males were found to reproduce (and again, 0 under this age). Numbers are biased low though, because males could have reproduced outside of the study area. Determinants of male reproductive success in American black bears. High rates of bear-caused injuries observed in captured males, and very low proportion of bears reproducing. However, some very young bears (likely incapable of out-fighting older adults) did succeed in reproducing. In addition, dominance is also extremely important to even the success of females. The relative importance of prey density and social dominance in determining energy intake by bears feeding on Pacific salmonSimilar is likely the case for male bears-social status is crucial to the ability to acquire food. For most foods dominance probably isn't as overwhelmingly important as for fishing, but still probably crucial. I recall plenty of anecdotes in books I have read. Many bear deaths are the result of conflicts with humans; it is likely many of these conflicts are the result of more dominant bears In Ben Kilham's book "Among the Bears" he describes many cases of black bears being driven away from natural food sources and forced to turn to other-often human-food sources. Many more examples of such cases exist-"Learning to Talk Bear" discusses a low ranking non-problem female grizzly who couldn't get enough food to successfully raise cubs; eventually at around 10 years old (I don't recall exactly how old) her body was found being eaten by a bear named the "Rottweiler Bear" (although they couldn't determine cause of death). The Rottweiler Bear-who had never caused any problems with people (but had somewhat of a history of eating bears) later fought the Mud Lake Bear, after which he diverted off his yearly path to some natural food items (I don't recall what exactly), and instead ate dog food. He was promptly shot to death by the dog's owners after this first offence in a lifetime clean record. I would be very interested in seeing more info the relationship between dominance, food acquiring ability, and reproductive success.
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Post by warsaw on Jun 19, 2012 2:03:44 GMT -9
First of all. Thanks for the interesting data . I figured I'd post the info for my reply to the "short winded big cats" thread hereOK. BTW, more flexible muscles (higher fiber length/moment arm ratio) have higher speed when resistance is low. A bear's adaptation for forelimb flexibility=adaptation for fast paw strike. Swipe from the bear's paw can lead to both blunt and penetrating trauma. BTW I found that "... A crushing mechanism or a focused blunt injury to the right upper quadrant compresses the ribs into the liver causing a stellate-type laceration across the dome and anterior surface of the right lobe, often termed a ‘‘bear-claw injury.’..." Yes. Also not a complete picture, because some can also kill large prey quickly: BTW "A lifetime of bears After three decades of studying these mighty animals, Alberta biologist Gord Stenhouse remains in awe at how clever, powerful – and vulnerable – they are, and at how much we still need to learn in order to save them from usStenhouse has seen a grizzly bear eat an elk while a pack of hungry wolves tried to move in. He has watched in amazement as a bear climbed a 2,700-metre peak in the depths of snow and ice for no apparent reason. And he was utterly spooked when he was bushwhacking along the banks of a stream, tracking a bear that was walking though the Hinton golf course while men and women were putting on greens. Most humbling perhaps was the sight of a small 110-kg bear that had killed a huge quarter-horse before burying it in the ground. “It looked like a front-end loader had gone in there and buried that horse,” he said. “It was a sobering reminder that these are awfully powerful animals.” www.ace-lab.org/_documents/Struzik2011EdmontonJournal.pdfThanks for the info...although I am skeptical of the moose decapitation accounts. I'm skeptical too! Anyway bear bear can decapitate a human with one swipe. "I agree, although even in areas not hunted by people it seems that ~80% of adult bear deaths are normally attributed to human causes (poaching, self defense, hit by car, etc)." Yes ,normally attributed to human causes ,but increase of the population and anthropogenic press on natural ecosystems can make a difference. "With extremely powerful animals such as bears, evolution has resulted in a minimum of serious intraspecific individual injury, and a maximum ritualization of agonistic behaviour, especially with reproductive units such as sows."Herrero There is no place for "ritualization of agonistic behaviour" "During these catastrophic food years" "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"
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Post by warsaw on Jun 19, 2012 23:30:04 GMT -9
What about length? That bear had the largest chest girth, and longest body length, but much lower weight than several others. What body weight was it giving up? Small abdominal girth, yes, but does that explain all of it? Would a starving bear no longer have a large chest girth? That bear did have badly warn teeth. The researchers would know much better than I. Were there any notes on its condition? First of all:"Khutzeymateen Valley grizzly bear study: final report" www.for.gov.bc.ca/hfd/pubs/docs/mr/Whr31.htmLook at the table: images47.fotosik.pl/383/65d92980ac5ef94b.jpgBoth GM09&GF43 have heavy tooth wear. Anyway,two contradictory statements ( poor condition &relatively powerful built.)can both be true. For example: " Killed bear was in poor condition, emaciated, with losses in the teeth. However, its dimensions must arouse awe. He was 210 cm in length along the back, the weight of 225 kg and a neck circumference of 90 cm. Hind paw dimensions: length 27 cm and width of 16.5 cm. Forefoot: length 17 cm, width 16.5 cm. " translate.google.pl/translate?js=n&prev=_t&hl=pl&ie=UTF-8&layout=2&eotf=1&sl=pl&tl=en&u=http%3A%2F%2Fwww.lasy.gov.pl%2Fzakladki%2Faktualnosci%2Fmis_birczaReply #4 Above: Very old 32 year old male brown bear named Boris, Munich Zoo.(B.W= 220 kg). www.myvideo.de/watch/6272953/Braunbaer_Boris_32_Jahre_DSCI1138_001shaggygod.proboards.com/index.cgi?board=horribilis&action=display&thread=671&page=1Reply #22 shaggygod.proboards.com/index.cgi?board=generalinfo&action=display&thread=669&page=2Even very old male can be relatively impressive. Not very impressive but ... "On Monday, the bear, one of the oldest ever captured in northwest Montana, was euthanized because of its poor condition and a history of breaking into buildings for food. The bear, known as “Stanley” or No. 8, was 24 to 27 years old, said Mike Madel, a Choteau-based grizzly bear management specialist with Montana Fish, Wildlife & Parks It weighed 429 pounds, which is considered small for a male living on the Rocky Mountain Front." montanagrizzlybears.wordpress.com/2011/09/26/fwp-puts-down-geezer-grizzly-from-rocky-mountain-front-2/"Manley said that the 3-year old adult male grizzly weighed 380 pounds and had been previously marked with an ear tag chip. Two years ago it was captured as a yearling in the valley with its sibling and an adult female grizzly. The group was relocated to the Spotted Bear area." montanagrizzlybears.wordpress.com/2011/09/26/grizzly-bear-caught-near-kalispell-relocated/BTW Above: Alpha boar who is aging and beginning to lose muscle mass, so that his pelvis and shoulder blades are prominent. www.naturefootage.com/video_clips/DZ116_0025"152 was the value of the largest male, not the average of 10+ year old males"Yes you're right. 152 was the value of the largest male, not the average of 10+ year old males. Or maybe a typo by author (female chest girth = incorrect)? Maybe, but its hard to say. I think it might be a typo by author here as well: GF43 total lenght= 143 .Maybe =193 ? Finally, in that list for 10.5+ year old males (body weight difference)^(1/3)=24% = base line. Everything above is more important for 10.5+ males than females (as increased faster than would be expected for the difference in weight), everything below less important (increased slower). "The adult male sample was small within older age-classes (age 7 years and older, N = 10) and did not provide a clear indication of the duration of growth" Maybe there is a problem? Age 7 -10 y.o, N = ? Sample of unknown size N Age 10 year and older N = ? Sample of unknown size N
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Post by warsaw on Jun 23, 2012 4:06:15 GMT -9
"...Brown bears (Ursus arctos L., 1758) are sexually dimorphic, with relative growth rate and body size that varies among age classes, seasons, and geographically across the range of the species (Rausch 1963; Pearson 1975; Glenn 1980; Kingsley et al. 1983, 1988; Blanchard 1987; McLellan 1994; Case and Buckland 1998; Stringham 1990; Hilderbrand et al. 1999; Zedrosser et al. 2006, 2007; Swenson et al. 2007). Sexual size dimorphism begins early in life (Glenn 1980; Kingsley et al. 1983, 1988; Blanchard 1987; Case and Buckland 1998) and is thought to be related to dominance competition among males to gain access to more females in estrus (McLellan 1994; Schwartz et al. 2003a; Zedrosser et al. 2007). Body mass is dynamic, gaining in summer when bears are active and feeding and losing in winter when bears are torpid (Pearson 1975; Blanchard 1987; Kingsley et al. 1983). Nutrition has been suspected to be the major factor producing geographic differences, with coastal salmon-eating Alaskan populations producing larger body sizes than interior populations that eat mostly plant matter and terrestrial meat (Rausch 1963; Stringham 1990; McLellan 1994; Hilderbrand et al. 1999; Ferguson and McLoughlin 2000; Gende and Quinn 2004). The reproductive success of brown bears is positively correlated to body size (Stringham 1990; McLellan 1994; Kovach et al. 2006; Zedrosser et al. 2007), which is inter-related to nutrition, growth rate, and age at maturation (Kingsley et al. 1983, 1988; Hilderbrand et al. 1999; Dahle and Swenson 2003; Dahle et al. 2006). As female body size increases, litter size and natality increase, while interbirth interval and age of primiparity decrease (Stringham 1990; McLellan 1994; Hilderbrand et al. 1999; Zedrosser et al. 2006). Similarly, larger males gain access to more females in estrus (Zedrosser et al. 2007). Therefore, because growth, age at maturation, and body size of brown bears can be used as a proxy for relative nutrition and reproductive success (Stringham 1990; McLellan 1994; Hilderbrand et al. 1999; Zedrosser et al. 2007)."... The estimated ages at 90% of the asymptotic body length were 2.8 for females and 4.6 for males. Both sexes continued their growth in spring body mass even longer and females were estimated to reach 90% of the asymptote at age 6.9 and males at age 12.4..." www.nrcresearchpress.com/doi/abs/10.1139/z11-088?journalCode=cjz
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Post by Ursus arctos on Jun 23, 2012 23:30:19 GMT -9
Swipe from the bear's paw can lead to both blunt and penetrating trauma. BTW I found that "... A crushing mechanism or a focused blunt injury to the right upper quadrant compresses the ribs into the liver causing a stellate-type laceration across the dome and anterior surface of the right lobe, often termed a ‘‘bear-claw injury.’..." Interesting. Googling the term reveals it is in fact occasionally used; I am guessing its origin is from a bear causing such an injury at least once? BTW "A lifetime of bears After three decades of studying these mighty animals, Alberta biologist Gord Stenhouse remains in awe at how clever, powerful – and vulnerable – they are, and at how much we still need to learn in order to save them from usStenhouse has seen a grizzly bear eat an elk while a pack of hungry wolves tried to move in. He has watched in amazement as a bear climbed a 2,700-metre peak in the depths of snow and ice for no apparent reason. And he was utterly spooked when he was bushwhacking along the banks of a stream, tracking a bear that was walking though the Hinton golf course while men and women were putting on greens. Most humbling perhaps was the sight of a small 110-kg bear that had killed a huge quarter-horse before burying it in the ground. “It looked like a front-end loader had gone in there and buried that horse,” he said. “It was a sobering reminder that these are awfully powerful animals.” www.ace-lab.org/_documents/Struzik2011EdmontonJournal.pdfHorses are very difficult prey. Such a small grizzly managing to take one is very impressive. Yes ,normally attributed to human causes ,but increase of the population and anthropogenic press on natural ecosystems can make a difference. "With extremely powerful animals such as bears, evolution has resulted in a minimum of serious intraspecific individual injury, and a maximum ritualization of agonistic behaviour, especially with reproductive units such as sows."Herrero There is no place for "ritualization of agonistic behaviour" "During these catastrophic food years" "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" I agree. There is also the youtube slide show of one brown bear killing another of similar size-for which other animals do we have slide shows or videos of intraspecific mortality events occurring? I provided plenty of evidence of bears having very high competition (including in their evolutionary history, based on Y/X chromosome mutation rates). I have a book "Reproductive Success Studies of Individual Variation in Contrasting Breeding Systems" which has chapters devoted to a variety of mammal species. I will hopefully be able to post info from them to put the info on bears in context. Mammals included include lions, Northern elephant seals, red deer, Savannah baboons-a variety of species that also have high levels of competition. What about length? That bear had the largest chest girth, and longest body length, but much lower weight than several others. What body weight was it giving up? Small abdominal girth, yes, but does that explain all of it? Would a starving bear no longer have a large chest girth? That bear did have badly warn teeth. The researchers would know much better than I. Were there any notes on its condition? First of all:"Khutzeymateen Valley grizzly bear study: final report" www.for.gov.bc.ca/hfd/pubs/docs/mr/Whr31.htmLook at the table: images47.fotosik.pl/383/65d92980ac5ef94b.jpgBoth GM09&GF43 have heavy tooth wear. If GF43's length and weight were both accurate, she is however still in good condition (a lot of weight on her frame). Anyway,two contradictory statements ( poor condition &relatively powerful built.)can both be true. For example: " Killed bear was in poor condition, emaciated, with losses in the teeth. However, its dimensions must arouse awe. He was 210 cm in length along the back, the weight of 225 kg and a neck circumference of 90 cm. Hind paw dimensions: length 27 cm and width of 16.5 cm. Forefoot: length 17 cm, width 16.5 cm. " translate.google.pl/translate?js=n&prev=_t&hl=pl&ie=UTF-8&layout=2&eotf=1&sl=pl&tl=en&u=http%3A%2F%2Fwww.lasy.gov.pl%2Fzakladki%2Faktualnosci%2Fmis_birczaReply #4 Above: Very old 32 year old male brown bear named Boris, Munich Zoo.(B.W= 220 kg). www.myvideo.de/watch/6272953/Braunbaer_Boris_32_Jahre_DSCI1138_001shaggygod.proboards.com/index.cgi?board=horribilis&action=display&thread=671&page=1Reply #22 shaggygod.proboards.com/index.cgi?board=generalinfo&action=display&thread=669&page=2Even very old male can be relatively impressive. Not very impressive but ... "On Monday, the bear, one of the oldest ever captured in northwest Montana, was euthanized because of its poor condition and a history of breaking into buildings for food. The bear, known as “Stanley” or No. 8, was 24 to 27 years old, said Mike Madel, a Choteau-based grizzly bear management specialist with Montana Fish, Wildlife & Parks It weighed 429 pounds, which is considered small for a male living on the Rocky Mountain Front." montanagrizzlybears.wordpress.com/2011/09/26/fwp-puts-down-geezer-grizzly-from-rocky-mountain-front-2/"Manley said that the 3-year old adult male grizzly weighed 380 pounds and had been previously marked with an ear tag chip. Two years ago it was captured as a yearling in the valley with its sibling and an adult female grizzly. The group was relocated to the Spotted Bear area." montanagrizzlybears.wordpress.com/2011/09/26/grizzly-bear-caught-near-kalispell-relocated/BTW Above: Alpha boar who is aging and beginning to lose muscle mass, so that his pelvis and shoulder blades are prominent. www.naturefootage.com/video_clips/DZ116_0025Well, Specific info: From "A Body-Condition Index for Ursids" by Marc Cattet, et al. Relationship between body condition index and body fat for black bears, r 2=0.63. Therefore correlation coefficient=0.79. Obviously fat + muscle mass/body size has some relationship with fat/body size because that makes up half the equation, but the relationship seems strong enough to indicate that more fat/total body length also indicates more muscle/total body length. Correlation isn't perfect though so it is possible. Also, in many populations (can't generalize to all; diet changes over the year differ from population to population) bears build a lot more fat and less lean tissue (such as muscle) in Autumn, while spring and summer are the opposite so fat and muscle may also not be that strongly correlated for that reason. BTW, the equation provided by the article: " Black bears and grizzly bears: BCI = (ln TBM – 3.21 · ln SLBL + 11.64) ÷ (0.29 – 0.017 · ln SLBL)SLBL= straight line body length, which wasn't provided in Khutzeymateen study (thanks for the link). Estimating that SLBL=0.75-0.8* contour length, using the above formula GM09 body condition = 0.5-1.5 0= average GM09 apparently in good condition? Other bears in much better than average condition? "A Body-Condition Index for Ursids" used grizzlies captured in Alberta. Maybe Alberta grizzly bears different from Khutzeymateen Valley and Yellowstone (Yellowstone bears also apparently have much higher than 0 BCI on average)? Although, yes, some old males can be impressive. Male 1124 fathered tied for fathering the most cubs out of any of the 46 males assumed to be in the area over a 6 year period. He was 26-28 years old while reproducing. "152 was the value of the largest male, not the average of 10+ year old males"Yes you're right. 152 was the value of the largest male, not the average of 10+ year old males. Or maybe a typo by author (female chest girth = incorrect)? Maybe, but its hard to say. I think it might be a typo by author here as well: GF43 total lenght= 143 .Maybe =193 ? Could be. BTW, equations the article produced relating chest girth to body mass: According to the equations, at equal weight females have higher chest girth. My guess: because at equal weight males have smaller (in length and height), more muscular bodies. Between species comparisons, where body shapes can be different however chest girth is useful because it can tell us about shape. Gorillas have short, thick (aka, robust) bodies. Ferrets have long, slender (aka, not gracile) bodies. Finally, in that list for 10.5+ year old males (body weight difference)^(1/3)=24% = base line. Everything above is more important for 10.5+ males than females (as increased faster than would be expected for the difference in weight), everything below less important (increased slower). "The adult male sample was small within older age-classes (age 7 years and older, N = 10) and did not provide a clear indication of the duration of growth" Maybe there is a problem? Age 7 -10 y.o, N = ? Sample of unknown size N Age 10 year and older N = ? Sample of unknown size N Males weighing 8.5, N= 2 Males weighing 10.5+, N=5 Females weighing 8.5, N=15 Females weighing 9.5, N=8 Females weighing 10.5+, N=48
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Post by warsaw on Jun 26, 2012 2:57:15 GMT -9
Interesting. Googling the term reveals it is in fact occasionally used; I am guessing its origin is from a bear causing such an injury at least once?I just noticed that in the medical literature this term was used to describe "A crushing mechanism or a focused blunt injury to the right upper quadrant compresses the ribs into the liver" I guess that this term is occasionally used to describe any "focused chest blunt injury " . I am guessing its origin is from a bear causing such an injury at least once?Yes,from a bear ,as the name suggests. "In Jasper National Park tourists watched a large, probably male, grizzly bear severely maul and kill a 150-pound-smaller male.23 The date, June 11, 1970, would have been during the end of the breeding season. A Canadian Wildlife Service autopsy of the dead bear revealed eighty-nine puncture wounds, a portion of the spleen protruding from the abdomen, a two-inch hole in the chest, a crushed rib cage, a broken right shoulder, a dislocated neck, a broken nose bridge, and a crushed skull." Broken rib can damage internal organs such as liver or lung . GM09 apparently in good condition?I'm not entirely certain, but neck:92 cm ,chest girth:155cm is impressive. Other bears in much better than average condition?I doubt it. (Yellowstone bears also apparently have much higher than 0 BCI on average)?I don't know. BTW I read recently that : Comments submitted to the US Fish and Wildlife Service regarding delisting of the Yellowstone Grizzly Bear DPS, Federal Register . Vol. 70 "Loss of genetic variability An isolated population of 600 bears requires gene flow from other populations to maintain and increase genetic variability. Current estimates of the genetic effective population size (Ne) of the Yellowstone population range from only 13-65 (Paetkau et al. 1998) to slightly over 100 (Miller and Waits 2003), we ll below the le vel of 500-5000 recommended for preventing genetic impoverishment. The retained genetic heterozygosity is estimated at 75% which is less than zoos manage for and the inbreeding coefficient of grizzly bears in the Yellowstone population is estimated at 0.125 (Gilpin, pers. comm.. 2006): this is what one would get from a marriage of first cousins. The proposed rule relies on genetic augmentation through importation of bears from other populations to avoid viability risks (e.g., inbreeding depression) associated with small populations. While this method has been examined theoretically (Miller and Waits 2003), the modeling exercise was based on the genetic variability within the NCDE remaining at current levels – which is not at all certai n given current and future pressures on that region. Further, the success rate of translocations is uncertain into hab itat that is already fully occupied by grizzlies. Of 4 females translocated into the Cabinet-Yaak ecosytem from 1990-1994, there is evidence of only one successfully breeding (Kasworm et al. 2004). Although her offspring may yet survive and breed, this eviden ce suggests that it may be necessary to translocate 8 or more female bears per generation in order to have 1-2 successful transplants. Current recommendations for the Ca binets are to introduce 12 females into the Cabinet mountains and 20 b ears each into the Canadian Purcell-Yaak and South Selkirk populations in a generation (Proctor et al. 2004) and the authors warn that it may take more that that to achieve the net gains predicte d by their models. It should be even more difficult for a translocated bear to become established and breed in the Yellowstone population which current demographic and population expansion data (Schwartz et al. 2005) indicate is currently at or near carrying capacity where competition will be greater than in the Cabinets. .." "...natural gene flow by bears moving across the landscape between the GYE and the NCDE may be several years away," park officials note in the document. "The average dispersal distance for subadult male grizzly bears in the GYE is 70 km. The distance between the two occupied ranges of the GYE and NCDE populations is currently 165 km, more than two times the average dispersal distance www.nationalparkstraveler.com/2012/01/yellowstone-national-park-report-unesco-outlines-issues-parks-genetic-isolation-human-pressures9287
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Post by warsaw on Jun 27, 2012 7:18:35 GMT -9
Males weighing 10.5+, N=5 Females weighing 8.5, N=15 Females weighing 9.5, N=8 Females weighing 10.5+, N=48
"Mean weights of 5 males and 25 females over 9 years of age were 389 kg and 207 " ?
"...Spring weights of female bears increased rapidly through age 5 years. Subsequent weight gain appear to depend mostly on a bear's individual size and seasonal physical condition. Serial between-year weights of ultimate-size bears indicated less than 10 percent variation. The heaviest male (18) weighed 442 kg and was 10 years old. The heaviest female (825) weighed 277 kg and was 15 years old. Mean weights of 5 males and 25 females over 9 years of age were 389 kg and 207 kg, respectively. The weights of these adults were consider- ably heavier than mean weights given by Pearson (1975) for adult (minimum age and dates of weighing not given) brown bears in interior Canada..."
"...The largest captured male (784) was 13 years and the largest captured female (825) was 15 years old. Differences in their respective sizes were as follows: weight, 390-275 kg; height at shoulder, 152-130 cm; total length,264-228 cm; hind-foot length, 44-38 cm; neck circumference, 90-80 cm; chest girth, 159-157 cm; body length, 140-127 cm; skull length, 473-403 mm; and zygomatic width, 311-251 mm. When all measure- ments were combined, mean total body size of 5 males over 9 years of age was 19 percent larger and their mean body weight was 88 percent heavier than the sizes and weights of 25 females of comparable age..."
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Post by Ursus arctos on Jun 27, 2012 23:37:48 GMT -9
Males weighing 10.5+, N=5 Females weighing 8.5, N=15 Females weighing 9.5, N=8 Females weighing 10.5+, N=48"Mean weights of 5 males and 25 females over 9 years of age were 389 kg and 207 " ? "...Spring weights of female bears increased rapidly through age 5 years. Subsequent weight gain appear to depend mostly on a bear's individual size and seasonal physical condition. Serial between-year weights of ultimate-size bears indicated less than 10 percent variation. The heaviest male (18) weighed 442 kg and was 10 years old. The heaviest female (825) weighed 277 kg and was 15 years old. Mean weights of 5 males and 25 females over 9 years of age were 389 kg and 207 kg, respectively. The weights of these adults were consider- ably heavier than mean weights given by Pearson (1975) for adult (minimum age and dates of weighing not given) brown bears in interior Canada..." "... The largest captured male (784) was 13 years and the largest captured female (825) was 15 years old. Differences in their respective sizes were as follows: weight, 390-275 kg; height at shoulder, 152-130 cm; total length,264-228 cm; hind-foot length, 44-38 cm; neck circumference, 90-80 cm; chest girth, 159-157 cm; body length, 140-127 cm; skull length, 473-403 mm; and zygomatic width, 311-251 mm. When all measure- ments were combined, mean total body size of 5 males over 9 years of age was 19 percent larger and their mean body weight was 88 percent heavier than the sizes and weights of 25 females of comparable age..." Oops-I didn't realize that samples were different in different graphs. I got those sample sizes from the hind foot length graph without double checking that all graphs were similar. Apparently they can be extremely different-which can largely invalidate the results of my analysis. GM09 apparently in good condition?I'm not entirely certain, but neck:92 cm ,chest girth:155cm is impressive. Other bears in much better than average condition?I doubt it. (Yellowstone bears also apparently have much higher than 0 BCI on average)?I don't know. Using the formula from the article "A Body Condition Index for Ursids" to calculate the body condition index appears to get >0 results far too often. Perhaps the population of bears used to derive it were not representative. BTW I read recently that : Comments submitted to the US Fish and Wildlife Service regarding delisting of the Yellowstone Grizzly Bear DPS, Federal Register . Vol. 70 "Loss of genetic variability An isolated population of 600 bears requires gene flow from other populations to maintain and increase genetic variability. Current estimates of the genetic effective population size (Ne) of the Yellowstone population range from only 13-65 (Paetkau et al. 1998) to slightly over 100 (Miller and Waits 2003), we ll below the le vel of 500-5000 recommended for preventing genetic impoverishment. The retained genetic heterozygosity is estimated at 75% which is less than zoos manage for and the inbreeding coefficient of grizzly bears in the Yellowstone population is estimated at 0.125 (Gilpin, pers. comm.. 2006): this is what one would get from a marriage of first cousins. The proposed rule relies on genetic augmentation through importation of bears from other populations to avoid viability risks (e.g., inbreeding depression) associated with small populations. While this method has been examined theoretically (Miller and Waits 2003), the modeling exercise was based on the genetic variability within the NCDE remaining at current levels – which is not at all certai n given current and future pressures on that region. Further, the success rate of translocations is uncertain into hab itat that is already fully occupied by grizzlies. Of 4 females translocated into the Cabinet-Yaak ecosytem from 1990-1994, there is evidence of only one successfully breeding (Kasworm et al. 2004). Although her offspring may yet survive and breed, this eviden ce suggests that it may be necessary to translocate 8 or more female bears per generation in order to have 1-2 successful transplants. Current recommendations for the Ca binets are to introduce 12 females into the Cabinet mountains and 20 b ears each into the Canadian Purcell-Yaak and South Selkirk populations in a generation (Proctor et al. 2004) and the authors warn that it may take more that that to achieve the net gains predicte d by their models. It should be even more difficult for a translocated bear to become established and breed in the Yellowstone population which current demographic and population expansion data (Schwartz et al. 2005) indicate is currently at or near carrying capacity where competition will be greater than in the Cabinets. .." Caused by small proportion of male bears actually being significant breeders. Thanks-more evidence for very high level of competition. Would be interesting to see how effective population size was calculated. I hope this research is heeded; would be great for the ranges to expand so that they meet and individual can regularly move between populations. Marriage of first cousins sounds much too close.
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Post by warsaw on Jun 29, 2012 11:47:15 GMT -9
Oops-I didn't realize that samples were different in different graphs. I got those sample sizes from the hind foot length graph without double checking that all graphs were similar. Apparently they can be extremely different-which can largely invalidate the results of my analysis.No problem. Using the formula from the article "A Body Condition Index for Ursids" to calculate the body condition index appears to get >0 results far too often. Perhaps the population of bears used to derive it were not representative.A Body-Condition Index for Ursids" used grizzlies captured in Alberta. Maybe Alberta grizzly bears different from Khutzeymateen Valley and Yellowstone (Yellowstone bears also apparently have much higher than 0 BCI on average)?Even in the same population "A Body-Condition Index "can change over time ,but I agree that grizzly bears different from Khutzeymateen Valley and Yellowstone . BTW: Some interesting articles "...From the perspective of the grizzly bear, the history of the Canadian West is similar to that of its southern neighbor. Grizzly bears once roamed as far east as the Manitoba-Ontario border, but as trappers and fur traders moved west in search of beaver, grizzly bears, buffalo and most other mammals became increasingly scarce. By the time settlers started flooding the prairies in the late 19th century, grizzlies were all but gone from the Great Plains, relegated instead to the boreal forests and tundra of the North and to the foothills and mountains of southern Canada. Today, most grizzly bear "populations" on the Canadian side of the border are considered threatened or nearly so. Only two, British Columbia’s Flathead and South Purcell grizzly bear "population units" contain "viable" populations, and only the Flathead provides the potential for meaningful connectivity with a recovering, though not recovered, population in the U.S.'s Northern Continental Divide Ecosystem. In Alberta, the provincial government's own Endangered Species Conservation Committee recommended that the Alberta grizzly be listed as a threatened species, but the government has refused to adopt the recommendation and has done little to reverse the trends threatening grizzly bears everywhere they still exist..." "...Since first being listed as an endan-gered species in 1975, the Yellowstone grizzly population has grown from an estimated range of 136-312 bears to 500-600 grizzlies at last count. The Yellowstone grizzlies also gained the distinction of becoming the most intensely studied bear population in the world during that time. But opponents of grizzly delisting, including around 250 scientists and researchers, sent a letter to the government protesting the delisting in March. They questioned whether the Yellowstone grizzly population is sustainable without endangered species protection, because the research numbers used in making the delisting decision include grizzly habitat outside Park boundaries: around 40 percent of the territory Yellowstone grizzlies roam is beyond the “designated recovery area.” Bears counted outside that recovery area are included in the delisting decision, and opponents claim that no plans have been made to ensure the grizzly bear’s survival as a viable species in those areas after delisting. Worries about pressures on the bear’s habitat include the effects of timber harvesting, mining, and residential development. Inbreeding within a confined Yellowstone grizzly population and even the possible effect of global warming on bear habitat are other concerns. Although the decision to delist grizzlies was based on criteria in accordance with the Endangered Species Act, a Natural Resources Defense Council press release called the government’s delisting plan “deeply flawed” and said it will “pursue every avenue possible, including a lawsuit and Congressional action, to protect the bears from being hunted and their habitat from being exploited for large-scale real estate and energy development. .."It may come as a surprise that Alberta harbors arguably the most threatened population of grizzly bears in Canada, if not North America. This situation has less to do with ecology or biology and everything to do with politics. South of the border, grizzly bears are protected by relatively strong legislation (the Endangered Species Act) and a science-based and well-funded recovery plan. While not perfect, these measures, kept on track by a reasonably robust environmental movement, seem able to ensure grizzly bears, perhaps even the small, isolated populations that hang on in places like the Selkirk, Cabinet-Yaak and Cascade mountains, will receive the attention, and habitat, they require to recover. The success of the recovering Yellowstone population, which has doubled over the last 30 years, is a good example of what is required to recover declining grizzly bear populations. Biologists have long recognized that access management is the key. Keeping road densities low and ensuring enough secure core habitat exists across the recovery zone are key components of recovering grizzly bears, and have worked well in the Greater Yellowstone Ecosystem. "The Yellowstone recovery plan is still the high bar," said grizzly bear biologist and Banff National Park warden Mike Gibeau. "And we’re nowhere near that in Alberta." More mountainwestnews.org/Page3.aspx?a=Perspectives&ID=95"...Since first being listed as an endan-gered species in 1975, the Yellowstone grizzly population has grown from an estimated range of 136-312 bears to 500-600 grizzlies at last count. The Yellowstone grizzlies also gained the distinction of becoming the most intensely studied bear population in the world during that time. But opponents of grizzly delisting, including around 250 scientists and researchers, sent a letter to the government protesting the delisting in March. They questioned whether the Yellowstone grizzly population is sustainable without endangered species protection, because the research numbers used in making the delisting decision include grizzly habitat outside Park boundaries: around 40 percent of the territory Yellowstone grizzlies roam is beyond the “designated recovery area.” Bears counted outside that recovery area are included in the delisting decision, and opponents claim that no plans have been made to ensure the grizzly bear’s survival as a viable species in those areas after delisting. Worries about pressures on the bear’s habitat include the effects of timber harvesting, mining, and residential development. Inbreeding within a confined Yellowstone grizzly population and even the possible effect of global warming on bear habitat are other concerns..." www.mtpioneer.com/archive-return-grizzly.htmTHE TOP TEN (OR 15) REASONS TO OPPOSE YELLOWSTONE GRIZZLY BEAR DELISTING www.grizzlypeople.com/topten.php"On 12 January 1999, Dr. Lance Craighead, noted expert on the grizzly bear, appeared before the House Fish, Wildlife, and Parks Committee and testified that his best guess was that the minimum viable population of grizzly bears was 1,000. Dr. Craighead said that the smallest known healthy population of bears was about 3,000. The number 1,000 reflected the minimum number of animals needed to maintain a gene pool. The proponents of the reintroduction of the bear know of this problem, but ignore it unless pressed, as Dr. Craighead was in the Committee hearing" shaggygod.proboards.com/index.cgi?action=display&board=generalinfo&thread=674&page=1With regard to this argumentation, the question arises :What is representative (healthy) grizzly population ? BTW
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