© 2019 Copyright by P. K. H. Groth, Denver, Colorado, USA All rights reserved - See contact page
Bear Behaviors
Bear Character: Bears are intelligent, strong, and interesting animals. Their physiology speaks of evolution that created a unique animal adapted to their sometimes harsh environment. Bears avoid and ignore people if they can. They become just annoyed when humans enter their personal space, and react violently if they or their young are threatened. Wild bears are less of a problem than bears conditioned to live with and demand food from people. To avoid bear problems, be vigilant in containing your food, pet food, greasy-smelling BBQ grill. Routinely have everyone follow camping procedures to keep food odors from snacks, in backpacks and on clothing. Bears are omnivores, eating mainly vegetation and meat if available. However, 85-95% of their food is vegetation in the form of grass, berries and tender leaves . They will also eat the inner bark of trees if necessary. Bears lack a rumen, so they can not digest cellulosic matter. Early spring vegetation is favored, since it is nutritious but not highly cellulosic. Food rapidly passes through the digestive system and appears in the scat. Studying the scat can indicate what the bears are currently eating. Stay away from these food sources, especially in the dawn and dusk hours. The digestion is so limited that berry seeds will germinate in the fertilizer dung. Bear lips are prehensile and flexible. Lips can nimbly strip berries and shrub leaves. Bears enter hyperphragia or panic feeding in late summer to early fall. They will spend up to twenty hours a day foraging enough to build up a five-inch layer of fat. Some authorities believe bears have the greatest smelling abilities of mammals. Their olfactory abilities are at least six times that of dogs. This is their advantage in locating food, predators, and danger. Hunters should comprehend for their safety that bears can readily locate gut piles and cached meat. Keep extremely vigilant when approaching your kill site in bear country! Bears are “plantigrade” (foot flat) like humans with flat feet that are not suitable to run fast like deer and elk. Black bears can run quickly in spurts, but not long at speed because their large, compact mass quickly overheats. Hence, they maraud their game prey with stalking and rapid short charges. The plantigrad feet provide good balance, so bears are able to stand and walk on their hind feet. They use this stance to better listen and observe with their mediocre eyes, which are deficient in the yellow-red-orange wavelengths. Black bears readily climb trees to forage, sleep or establish clawed “chemical information” scent posting trees. Bear communication is largely by body language that expresses dominance, subordination, or other intent. Nervous bears may salivate and froth, like humans get sweaty palms. Frightened bears vocalize defensively with guttural sounds, swatting the ground, stomping and giving nasal snort air blasts. You may hear bear vocalizations at blackbear.org and North American Bear Center. Bears are a “habitat indicator species”. A healthy population is possible when the vegetation and wildlife are in balance with good biodiversity. Bear Life Cycle: The life cycles are interesting. Bears mate during four to five days in April to May, depending on the geographic/climate location. This is the only time male and female are together; the remaining eighteen months she has a fatherless family. Female sows become reproductive at age 3 to five years, and sometimes as late as seven years. Since the lifespan of bears is only 18 years (oldest known was 31 years), this means sows can have only six litters per lifetime. Bear population growth is generally slow. Sows impregnated in spring carry the arrested fertilized egg until October or November. Only if the sow has gained enough fat for winter survival of mother and cubs will the egg become implanted and begin dividing. Lean sows absorb the eggs and remain barren for that year. Eleven-ounce cubs are born during torpor/hibernation, most commonly as two, but ranging from one to five. Lactation aroma draws them to suckle and rapidly gain weight from the rich milk as the slow sleeps. Hybernating bears give birth without waking and the cubs naturally nurse. However, the sow’s heart rate will immediately spike and awaken her if you come within 50 feet of the den. Remember, a den may be a pile of brush and leaves in the open. Cubs remain with their teaching mother for one and a half years. They learn all the survival skills by observation and constant trial and error. Their inquisitiveness accelerates learning. This learning method is carried into adulthood, allowing bears to get into just about any man made food container. Cubs must complete a one year cycle to learn how to find a winter lair and eat enough to survive hibernation. That is why hunting regulations prohibit shooting a sow with cubs. Bears’ heart rate is normally 40- 50 bpm, but slows to 8 bpm when in torpor. Body temperatures insignificantly decline. Cub survival rate is only 50% because of natural hazards. This includes marauding and cannibalization of cubs (especially male cubs) by encountered boars which are never a part of the family except when mating. Surviving male cubs must leave the territory of resident boars. Female cubs have to leave mother, but may be tolerated if they remain independent and distant to the sows core territory. Bears Miracle “Hibernation” and Non-Urination Explained: Bears reach a point in the hyperphragia feeding cycle when they have accumulated enough fat to survive a typical winter. Eating five times their normal daily calories results in accumulating fat up to five inches thick. Their appetite wanes and then ceases as escalating fat cell numbers collectively elevate and release leptin, a satiety hormone. A second reason for the end of hyperphraga is the dwindling amount of available food, and the need to conserve energy rather than waste it foraging over an ever wider area to find sparse, low nutrition resources. Food gathering inefficiency is not long tolerated in nature. If you have crossed beyond the point of using more energy searching for food than the fall food supply has to offer, you have to yield to an alternative. One alternative is to reduce or shut down metabolism. A good way is to hibernate until the food supply increases. A prime example is the western ground squirrel. In the spring they are abundant and rapidly reproduce. With the competition for declining food supplies, they resort to premature hibernation. In unusually hot summers the squirrels almost all instantaneously disappear into underground burrows. They resort to hibernation in perhaps July and not emerge until the next April or even May. Adaptation to changing food supplies is a survival necessity for the species. Bears look for dens when their appetite crashes. Black bears locate caves, brush piles, timber tangles, nooks under toppled tree roots, or even in early-snow snow shelters if necessary. Grizzlies dig tunnels with dens into hillsides. The den floor is lined with forest duff for comfort, and to permit give warmth and sanitation to hibernation- period cubs. Do bears actually hibernate? Hibernation historically has been defined as a constant sleep accompanied with significantly lower body temperature, a condition that lowers metabolism and saves energy. However, bears have only a slightly lower temperature as indicated by rectal measurement. Measurement is a risky adventure, especially since the annoyed bear can awaken. A more accurate new term to use is torpor. This is an environmental-induced drowsiness and lethargy in bears rather than deep sleep. In his fascinating book “Winter World” naturalist physiologist Bernt Heinrich reviews emerging scientific studies. These science observations of bears could have far-reaching effects on us mortal humans – from diabetes to space travel survival. I think it could also open profound doors to genetic manipulation of the human genome: aging, adjusting to a poisoned atmosphere, living on currently indigestible foods, and extending life through proper sleep (without side effect diseases and conditions). Bear Urination During Torpor: Bears do not defecate nor urinate while hibernating, The loss of appetite immediately prior to hibernation and the consumption of stored body fat results in little solid waste during the winter. An enigma of bear hibernation has been how a large mammal can avoid drinking water, never urinate for the long hibernation/torpor period and still not lose muscle and bone mass. If a bear’s kidneys were to shut down, the result should be ever increasing blood urea and nitrogen content. This should kill the bear with systemic sepsis. Ingeniously, nature prevents this from happening. So, how do bears not drink or urinate for months, yet still emerge strong after months of hibernation. The research of R. A. Nelson and Dianne L. Steiger (U. Illinois) and T. I. Beck (Colorado Division of Wildlife) provides startling revelations. Bears do not produce much urea as humans and other mammals. Bears are omnivorous and consume protein during the year, but in the winter, their bodies use stored fat, which does not metabolize into much nitrogen-rich urea. Water is recycled and the small amount of urea the sleeping bear produces is converted into creatine. In turn, the creatine is converted into protein that is used to continually replace muscle mass as muscle cells perish. This explains why bears emerge from hibernation “fit as a fiddle”, as muscularly strong as when they entered hibernation/torpor. Another ultimate solution of nature! Importance of Hibernation to Humans: There is more to the bear hibernation mystery that we do not yet know. In the weightlessness of space, astronauts lose three to 13% of bone mass in as little as two weeks. Muscle loss was similar. Paraplegic accident victims can lose 30% of bone mass in the first half year. So how do immobile bears retain bone mass during their long sleep? The answer is not yet clear, but the question must be pursued for the good of human destiny. Especially if we intend to venture into space with long periods of inactivity, without gravity nor serious necessary stress on our bodies. Bernt Heinrich’s book “Why I Run” states that humans were always active throughout evolutionary history. Survival depended on activity. We harnessed machines and technology and now can avoid stresses NECESSARY for our bodies to remain healthy. The results are becoming disastrous. One in three adults is sedentary. Diabetes is linked to inactivity, heart problems and stroke. We are so chained to using i-phones that manufacturers are designing door bells for thumbs because the modern population is losing the ability to automatically use forefingers. We no longer use our bodies throughout life. The window of active living becomes short due to the lack of exercise, sedentary obeisity, and joint failure. We know we should use our body. Adolescents need exercise to stress bones during development so that bone mass becomes strong, and muscles and ligaments adequately and perfectly align to the body. However, As Heinrich states: “Most of the American population subjects itself to the physical stress of inactivity”.
© 2016 -2017 Copyright by P. K. H. Groth, Denver, Colorado, USA All rights reserved - See contact page.
Bear Character: Bears are intelligent, strong, and interesting animals. Their physiology speaks of evolution that created a unique animal adapted to their sometimes harsh environment. Bears avoid and ignore people if they can. They become just annoyed when humans enter their personal space, and react violently if they or their young are threatened. Wild bears are less of a problem than bears conditioned to live with and demand food from people. To avoid bear problems, be vigilant in containing your food, pet food, greasy-smelling BBQ grill. Routinely have everyone follow camping procedures to keep food odors from snacks, in backpacks and on clothing. Bears are omnivores, eating mainly vegetation and meat if available. However, 85-95% of their food is vegetation in the form of grass, berries and tender leaves . They will also eat the inner bark of trees if necessary. Bears lack a rumen, so they can not digest cellulosic matter. Early spring vegetation is favored, since it is nutritious but not highly cellulosic. Food rapidly passes through the digestive system and appears in the scat. Studying the scat can indicate what the bears are currently eating. Stay away from these food sources, especially in the dawn and dusk hours. The digestion is so limited that berry seeds will germinate in the fertilizer dung. Bear lips are prehensile and flexible. Lips can nimbly strip berries and shrub leaves. Bears enter hyperphragia or panic feeding in late summer to early fall. They will spend up to twenty hours a day foraging enough to build up a five-inch layer of fat. Some authorities believe bears have the greatest smelling abilities of mammals. Their olfactory abilities are at least six times that of dogs. This is their advantage in locating food, predators, and danger. Hunters should comprehend for their safety that bears can readily locate gut piles and cached meat. Keep extremely vigilant when approaching your kill site in bear country! Bears are “plantigrade” (foot flat) like humans with flat feet that are not suitable to run fast like deer and elk. Black bears can run quickly in spurts, but not long at speed because their large, compact mass quickly overheats. Hence, they maraud their game prey with stalking and rapid short charges. The plantigrad feet provide good balance, so bears are able to stand and walk on their hind feet. They use this stance to better listen and observe with their mediocre eyes, which are deficient in the yellow-red- orange wavelengths. Black bears readily climb trees to forage, sleep or establish clawed “chemical information” scent posting trees. Bear communication is largely by body language that expresses dominance, subordination, or other intent. Nervous bears may salivate and froth, like humans get sweaty palms. Frightened bears vocalize defensively with guttural sounds, swatting the ground, stomping and giving nasal snort air blasts. You may hear bear vocalizations at blackbear.org and North American Bear Center. Bears are a “habitat indicator species”. A healthy population is possible when the vegetation and wildlife are in balance with good biodiversity. Bear Life Cycle: The life cycles are interesting. Bears mate during four to five days in April to May, depending on the geographic/climate location. This is the only time male and female are together; the remaining eighteen months she has a fatherless family. Female sows become reproductive at age 3 to five years, and sometimes as late as seven years. Since the lifespan of bears is only 18 years (oldest known was 31 years), this means sows can have only six litters per lifetime. Bear population growth is generally slow. Sows impregnated in spring carry the arrested fertilized egg until October or November. Only if the sow has gained enough fat for winter survival of mother and cubs will the egg become implanted and begin dividing. Lean sows absorb the eggs and remain barren for that year. Eleven-ounce cubs are born during torpor/hibernation, most commonly as two, but ranging from one to five. Lactation aroma draws them to suckle and rapidly gain weight from the rich milk as the slow sleeps. Hybernating bears give birth without waking and the cubs naturally nurse. However, the sow’s heart rate will immediately spike and awaken her if you come within 50 feet of the den. Remember, a den may be a pile of brush and leaves in the open. Cubs remain with their teaching mother for one and a half years. They learn all the survival skills by observation and constant trial and error. Their inquisitiveness accelerates learning. This learning method is carried into adulthood, allowing bears to get into just about any man made food container. Cubs must complete a one year cycle to learn how to find a winter lair and eat enough to survive hibernation. That is why hunting regulations prohibit shooting a sow with cubs. Bears’ heart rate is normally 40-50 bpm, but slows to 8 bpm when in torpor. Body temperatures insignificantly decline. Cub survival rate is only 50% because of natural hazards. This includes marauding and cannibalization of cubs (especially male cubs) by encountered boars which are never a part of the family except when mating. Surviving male cubs must leave the territory of resident boars. Female cubs have to leave mother, but may be tolerated if they remain independent and distant to the sows core territory. Bears Miracle “Hibernation” and Non- Urination Explained: Bears reach a point in the hyperphragia feeding cycle when they have accumulated enough fat to survive a typical winter. Eating five times their normal daily calories results in accumulating fat up to five inches thick. Their appetite wanes and then ceases as escalating fat cell numbers collectively elevate and release leptin, a satiety hormone. A second reason for the end of hyperphraga is the dwindling amount of available food, and the need to conserve energy rather than waste it foraging over an ever wider area to find sparse, low nutrition resources. Food gathering inefficiency is not long tolerated in nature. If you have crossed beyond the point of using more energy searching for food than the fall food supply has to offer, you have to yield to an alternative. One alternative is to reduce or shut down metabolism. A good way is to hibernate until the food supply increases. A prime example is the western ground squirrel. In the spring they are abundant and rapidly reproduce. With the competition for declining food supplies, they resort to premature hibernation. In unusually hot summers the squirrels almost all instantaneously disappear into underground burrows. They resort to hibernation in perhaps July and not emerge until the next April or even May. Adaptation to changing food supplies is a survival necessity for the species. Bears look for dens when their appetite crashes. Black bears locate caves, brush piles, timber tangles, nooks under toppled tree roots, or even in early-snow snow shelters if necessary. Grizzlies dig tunnels with dens into hillsides. The den floor is lined with forest duff for comfort, and to permit give warmth and sanitation to hibernation- period cubs. Do bears actually hibernate? Hibernation historically has been defined as a constant sleep accompanied with significantly lower body temperature, a condition that lowers metabolism and saves energy. However, bears have only a slightly lower temperature as indicated by rectal measurement. Measurement is a risky adventure, especially since the annoyed bear can awaken. A more accurate new term to use is torpor. This is an environmental-induced drowsiness and lethargy in bears rather than deep sleep. In his fascinating book “Winter World” naturalist physiologist Bernt Heinrich reviews emerging scientific studies. These science observations of bears could have far-reaching effects on us mortal humans – from diabetes to space travel survival. I think it could also open profound doors to genetic manipulation of the human genome: aging, adjusting to a poisoned atmosphere, living on currently indigestible foods, and extending life through proper sleep (without side effect diseases and conditions). Bear Urination During Torpor: Bears do not defecate nor urinate while hibernating, The loss of appetite immediately prior to hibernation and the consumption of stored body fat results in little solid waste during the winter. An enigma of bear hibernation has been how a large mammal can avoid drinking water, never urinate for the long hibernation/torpor period and still not lose muscle and bone mass. If a bear’s kidneys were to shut down, the result should be ever increasing blood urea and nitrogen content. This should kill the bear with systemic sepsis. Ingeniously, nature prevents this from happening. So, how do bears not drink or urinate for months, yet still emerge strong after months of hibernation. The research of R. A. Nelson and Dianne L. Steiger (U. Illinois) and T. I. Beck (Colorado Division of Wildlife) provides startling revelations. Bears do not produce much urea as humans and other mammals. Bears are omnivorous and consume protein during the year, but in the winter, their bodies use stored fat, which does not metabolize into much nitrogen-rich urea. Water is recycled and the small amount of urea the sleeping bear produces is converted into creatine. In turn, the creatine is converted into protein that is used to continually replace muscle mass as muscle cells perish. This explains why bears emerge from hibernation “fit as a fiddle”, as muscularly strong as when they entered hibernation/torpor. Another ultimate solution of nature! Importance of Hibernation to Humans: There is more to the bear hibernation mystery that we do not yet know. In the weightlessness of space, astronauts lose three to 13% of bone mass in as
Bear Character and Biology
Index Index