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Post by brobear on Mar 26, 2017 4:23:08 GMT -5
www.livescience.com/7622-huge-cave-bears-disappeared.html Enormous cave bears that once inhabited Europe were the first of the mega-mammals to die out, going extinct around 13 millennia earlier than was previously thought, according to a new estimate. Why'd they go? In part because they were vegetarians. The new extinction date, 27,800 years ago, coincides with a period of significant climate change, known as the Last Glacial Maximum, when a marked cooling in temperature resulted in a reduction or total loss of the vegetation that the cave bears ate (today’s brown bears are omnivores). The loss of this food supply led to the extinction of the cave bear, Ursus spelaeus, one of a group of "megafauna" — including the woolly mammoth, woolly rhinoceros, giant deer and cave lion — to disappear during the last Ice Age, the researchers wrote in a research paper published online Nov. 26 in the journal Boreas. Mysterious disappearance Over the years, numerous cave bear remains have been discovered in caves where the animals probably died during winter hibernation. Cave bears were huge, with males growing up to around 2,200 pounds (1,000 kg). The maximum recorded weight of both Kodiak bears and polar bears — the largest bears living today — is 1,760 pounds (800 kg), with averages of around 1,100 pounds (500 kg). During the Middle Ages, the bones of cave bears, thought to be the remains of dragons, were collected and used for medicine, the researchers say. The question of what caused cave bears, woolly mammoths and the other large mammals to go extinct has been a mystery. Some researchers think humans hunted the mega-mammals to extinction, but researcher Martina Pacher of the University of Vienna and her colleague Anthony J. Stuart of the Natural History Museum, London, found no convincing evidence for this idea regarding cave bears. Another theory is that some virus or bacteria could have sickened populations of mega-mammals, but Pacher and Stuart think such a "hyperdisease" is unlikely to explain the timing of the extinctions or the fact that body sizes of the dying-out animals varied so much. 'One of the earliest to disappear' Pacher used new data and existing records of radiocarbon dating on cave bear remains to construct the new chronology for cave bear extinction that supports the climate change scenario. "Our work shows that the cave bear, among the megafauna that became extinct during the Last Glacial period in Europe, was one of the earliest to disappear," Pacher said. "Other, later extinctions happened at different times within the last 15,000 years." Many scientists previously claimed that cave bears survived until at least 15,000 years ago, but the methodology of these earlier studies included errors in dating as well as confusion between cave bear and brown bear remains, Pacher and Stuart say, so they excluded those data from the analysis. Pacher and Stuart also concluded, from evidence on skull anatomy, bone collagen and teeth, that these extinct mammals were predominantly vegetarian, eating a specialized diet of high-quality plants. Compared with other megafaunal species that would also become extinct, the cave bear had a relatively restricted geographical range, being confined to Europe (ranging from Spain to the Ural Mountains in Russia), which may offer an explanation as to why it died out so much earlier than the rest. "Its highly specialized mode of life, especially a diet of high-quality plants, and its restricted distribution left it vulnerable to extinction as the climate cooled and its food source diminished," Pacher said. Why did the brown bear survive? The brown bear, with which Ursus spelaeus shares a common ancestor, was spread throughout Europe and much of northern Asia and has survived to the present day. "A fundamental question to be answered by future research is: why did the brown bear survive to the present day, while the cave bear did not?" Stuart said. Answers to this question may involve different dietary preferences, hibernation strategies, geographical ranges, habitat preferences and perhaps predation by humans. Despite more than 200 years of scientific study — beginning in 1794 when anatomist Johann Rosenmüller first described bones from the Zoolithenhöhle in Bavaria as belonging to a new extinct species, which he called cave bear — the timing and cause of its extinction remain controversial. The research was funded by Natural Environment Research Council UK, the Cultural Grant of Lower Austria and the EU project: AlpiNet Culture 2000.
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Post by brobear on Mar 26, 2017 4:23:55 GMT -5
Giant Cave Bear - Ursus spelaeus spelaeus.
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Post by brobear on Mar 26, 2017 4:34:19 GMT -5
www.crystalinks.com/fossilbear.html phys.org/news/2010-08-true-extinction-cave-revealed.html The cave bear started to become extinct in Europe 24,000 years ago, but until now the cause was unknown. An international team of scientists has analysed mitochondrial DNA sequences from 17 new fossil samples, and compared these with the modern brown bear. The results show that the decline of the cave bear started 50,000 years ago, and was caused more by human expansion than by climate change. "The decline in the genetic diversity of the cave bear (Ursus spelaeus) began around 50,000 years ago, much earlier than previously suggested, at a time when no major climate change was taking place, but which does coincide with the start of human expansion", Aurora Grandal-D'Anglade, co-author of the study and a researcher at the University Institute of Geology of the University of Coruna, tells SINC. According to the research study, published in the journal Molecular Biology and Evolution, radiocarbon dating of the fossil remains shows that the cave bear ceased to be abundant in Central Europe around 35,000 years ago. "This can be attributed to increasing human expansion and the resulting competition between humans and bears for land and shelter", explains the scientist, who links this with the scarce fossil representation of the bear's prey in the abundant fossil record of this species. In order to reach their conclusions, the team of scientists, led by the Max Planck Institute for Evolutionary Anthropology (Germany) studied mitochondrial DNA sequences from bear fossils in European deposits (Siberia, Ukraine, Central Europe and the Iberian Peninsula, specifically Galicia), and carried out a Bayesian analysis (of statistical probability). The scientists also made comparisons with the modern brown bear (Ursus arctos) and with fossil samples of this species of bear, and managed to show why one became extinct and the other did not. In order to demonstrate this, the study analysed 59 cave bear DNA sequences and 40 from the brown bear, from between 60,000 and 24,000 years ago for the cave bear and from 80,000 years ago up to the present day for the brown bear. Decline of the caves, extinction of the bears The impoverishment of ecosystems during the last glacial maximum was "the 'coup de grace' for this species, which was already in rapid decline", the author explains. The present day brown bear did not suffer the same fate and has survived until today for one simple reason - brown bears did not depend so heavily on the cave habitat, which was becoming degraded, and this is why they did not follow the same pattern as the cave bears. "Brown bears rely on less specific shelters for hibernation. In fact, their fossil remains are not very numerous in cave deposits", the Galician researcher says. The definitive extinction of the cave bear "broadly" coincides with the last cooling of the climate during the Pleistocene (between 25,000 and 18,000 years ago), which may have led to a reduction in shelter and the vegetation that the animals fed on. The cave bear inhabited Europe during the Late Pleistocene and became definitively extinct around 24,000 years ago, although it held out for a few thousand years longer in some areas, such as the north west of the Iberian Peninsula, than in other places. This ursid was a large animal, weighing 500 kg on average, and was largely a herbivore. The bear hibernated in the depths of limestone caves, where the remains of individuals that died during hibernation slowly accumulated over time.
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Post by brobear on Mar 26, 2017 4:53:01 GMT -5
www.sciencedaily.com/releases/2016/08/160823083557.htm Date: August 23, 2016 Source: Senckenberg Research Institute and Natural History Museum Summary: Scientists have studied the feeding habits of the extinct Cave Bear. Based on the isotope composition in the collagen of the bears' bones, they were able to show that the large mammals subsisted on a purely vegan diet. The team proposes that it was this inflexible diet that led to the Cave Bear's extinction approximately 25,000 years ago. Senckenberg scientists have studied the feeding habits of the extinct Cave Bear. Based on the isotope composition in the collagen of the bears' bones, they were able to show that the large mammals subsisted on a purely vegan diet. In the study, recently published in the scientific publication Journal of Quaternary Science, the international team proposes that it was this inflexible diet that led to the Cave Bear's extinction approximately 25,000 years ago. Today's Brown Bears are omnivores. Depending on the time of year, they devour plants, mushrooms, berries and small to larger mammals, but they will also take fish and insects. "The Cave Bear is a very different story," says Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at the University of Tübingen, and he continues to explain, "According to our newest findings, these extinct relatives of the Brown Bear lived on a strictly vegan diet." Cave Bears (Ursus spelaeus) lived in Europe during the most recent glacial period, approximately 400,000 years ago, until they became extinct about 25,000 years ago. With a length of 3.5 meters and a height of 1.7 meters at the shoulder, these bears, which ranged from Northern Spain to the Urals, were noticeably larger than their modern-day relatives. Despite their name, they did not actually live in caves but only used them for hibernation. Nevertheless, the occasional death of animals in various European caves over several tens of thousands of years eventually led to enormous accumulations of bones and teeth from these large fur-bearing animals. Several of these bones from the "Goyet Cave" in Belgium have now been examined by the international team around Prof. Bocherens, with a special focus on the Cave Bear's diet. "We were particularly interested in what exactly the Cave Bears ate, and whether there is a connection between their diet and their extinction," explains the biogeologist from Tübingen. To this end, scientists from Japan, Canada, Belgium and Germany conducted isotope studies on the collagen from the bears' bones. Collagen is an essential organic component of the connective tissue in bones, teeth, cartilage, tendons, ligaments and the skin. The examination of the isotope composition of individual amino acids in the collagen shows that the bears lived on a strictly vegan diet. "Similar to today's Giant Panda, the Cave Bears were therefore extremely inflexible in regard to their food," adds Bocherens, and he continues, "We assume that this unbalanced diet, in combination with the reduced supply of plants during the last ice age, ultimately led to the Cave Bear's extinction." Previously, there had been much speculation as to the cause of the large bears' disappearance. Was it due to increasing hunting pressure from humans? The changing temperatures, or the lack of food? "We believe that the reliance on a purely vegan diet was a crucial reason for the Cave Bear's extinction," explains Bocherens. During the investigation, another interesting aspect came to light. Even the collagen of two Cave Bear cubs indicated a vegan diet -- despite the fact that they were suckled by their mother. The scientists interpret this finding as a reflection of the nursing female's diet. "We now intend to examine additional Cave Bear bones from various European locations with this new method, as well as conducting controlled feeding experiments with modern bears, in order to further solidify our proposition," adds Bocherens by way of a preview. Story Source: Materials provided by Senckenberg Research Institute and Natural History Museum. Note: Content may be edited for style and length.
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Post by brobear on Mar 26, 2017 5:13:22 GMT -5
www.ncbi.nlm.nih.gov/pmc/articles/PMC5059403/Retreat and extinction of the Late Pleistocene cave bear (Ursus spelaeus sensu lato) The cave bear (Ursus spelaeus sensu lato) is a typical representative of Pleistocene megafauna which became extinct at the end of the Last Glacial. Detailed knowledge of cave bear extinction could explain this spectacular ecological transformation. The paper provides a report on the youngest remains of the cave bear dated to 20,930 ± 140 14C years before present (BP). Ancient DNA analyses proved its affiliation to the Ursus ingressus haplotype. Using this record and 205 other dates, we determined, following eight approaches, the extinction time of this mammal at 26,100–24,300 cal. years BP. The time is only slightly earlier, i.e. 27,000–26,100 cal. years BP, when young dates without associated collagen data are excluded. The demise of cave bear falls within the coldest phase of the last glacial period, Greenland Stadial 3. This finding and the significant decrease in the cave bear records with cooling indicate that the drastic climatic changes were responsible for its extinction. Climate deterioration lowered vegetation productivity, on which the cave bear strongly depended as a strict herbivore. The distribution of the last cave bear records in Europe suggests that this animal was vanishing by fragmentation into subpopulations occupying small habitats. One of them was the Kraków-Częstochowa Upland in Poland, where we discovered the latest record of the cave bear and also two other, younger than 25,000 14C years BP. The relatively long survival of this bear in karst regions may result from suitable microclimate and continuous access to water provided by deep aquifers, indicating a refugial role of such regions in the Pleistocene for many species. The extinction of large-bodied mammals (called megafauna) is one of the most characteristic and inherent features of the Late Pleistocene. The disappearance began 50,000 years ago and affected a substantial number of mammalian genera, e.g. 36 % of them in Eurasia, 72 % in North America and 83 % in South America (Barnosky et al. 2004). Both the climate and environment changes, as well as human influence, are believed to be the main causes of this extinction (Barnosky et al. 2004; Cooper et al. 2015; Koch and Barnosky 2006; Lorenzen et al. 2011; Stuart 2015). The climate shift was sufficient to explain the fauna transformation in some cases, but in others, a combination of climatic and anthropogenic effects was most probably responsible for this phenomenon (Cooper et al. 2015; Lorenzen et al. 2011). A typical representative of megafauna is the cave bear (Ursus spelaeus sensu lato), which was one of the most widespread mammals in Eurasia in the Late Pleistocene. It evolved from Middle Pleistocene Ursus deningeri and developed into several forms which can be distinguished at morphological and genetic levels. Two main European forms in the species rank, which diverged probably between 414,000 and 173,000 years ago, were identified as Ursus ingressus, which inhabited south-eastern and central Europe as well as the Ural (Baca et al. 2014; Rabeder et al. 2004b), and U. spelaeus, which lived mainly in western Europe, although its remains were found also in the Altai (Knapp et al. 2009; Rabeder et al. 2004b). According to the rules of the International Code of Zoological Nomenclature, U. ingressus should, however, be called Ursus kanivetz, because under the latter name a bear from Medvezhiya Cave in the Ural was first described by Vereshchagin (1973) (see also Baryshnikov and Puzachenko (2011)). Further studies of ancient DNA showed that the haplotype from Medvezhiya Cave is clustered with others from Europe, described as U. ingressus (Baca et al. 2012; Knapp et al. 2009). Additionally, two small cave bear forms that had preserved some primitive traits were distinguished as subspecies of U. spelaeus: U. spelaeus eremus and U. spelaeus ladinicus (Rabeder and Hofreiter 2004; Rabeder et al. 2004a). Their distribution was confined to the high alpine caves in Austria and Italy. Recently, another major group of large cave bears from the Caucasus and the Yana River region in eastern Siberia was discovered (Baryshnikov 1998; Knapp et al. 2009). Initially, they were named Ursus deningeri kudarensis, but recent genetic studies suggest that they should be considered a third species, U rsus kudarensis (Stiller et al. 2014). By the end of the Pleistocene, all these cave bear forms were extinct and the causes and timing of this process have been debated over the recent years. Direct radiocarbon dating indicates that the last cave bears became extinct prior to the Last Glacial Maximum (LGM) and disappeared from fossil record quite simultaneously in different parts of Europe about 24,000 14C years before present (BP) (about 28,000 cal. years BP) (Bocherens et al. 2014; Hofreiter et al. 2002; Martini et al. 2014; Pacher and Stuart 2009; Sabol et al. 2014; Wojtal et al. 2015). Paleogenetic analyses showed, nonetheless, that the demise of cave bears started ca. 50,000 radiocarbon years BP (Stiller et al. 2010), thus about 25,000 years before their final extinction. It has been argued that apart from the changing climate (Pacher and Stuart 2009; Stuart and Lister 2007), several other factors contributed to the decline of cave bears. There is compelling evidence for human hunting of cave bears (Münzel et al. 2011; Wojtal et al. 2015), as well as their competition for caves as a shelter (Grayson and Delpech 2003). Possibly, also large carnivores like cave lion (Panthera spelaea) and cave hyena (Crocuta crocuta spelaea) hunted cave bears while these were hibernating (Bocherens et al. 2011a; Diedrich 2014). The paper reports on, so far, the youngest remains of the cave bear from the Stajnia Cave located in the Częstochowa Upland, Poland. In this region were also found other quite young fossils of this bear in two caves, Komarowa and Deszczowa (Nadachowski et al. 2009; Wojtal 2007; Wojtal et al. 2015). Genetic analyses confirmed beyond doubt the affiliation of this specimen to the cave bear, whereas the direct radiocarbon dating provided the evidence for the survival of this species into the Greenland stadial GS-3. Using this new dating and more than 200 published dates, we estimated the time of cave bear extinction and discussed potential factors of its disappearance and survival in karst regions. *Much more info at site posted.
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Post by brobear on Mar 26, 2017 5:22:53 GMT -5
www.sciencedirect.com/science/article/pii/S1040618213007921 Quaternary International Volumes 339–340, 7 August 2014, Pages 148–163 Fossil remains in karst and their role in reconstructing Quaternary paleoclimate and paleoenvironments Behavioural ecology of Late Pleistocene bears (Ursus spelaeus, Ursus ingressus): Insight from stable isotopes (C, N, O) and tooth microwear Several types of bears lived in Europe during the Late Pleistocene. Some of them, such as cave bears (Ursus s. spelaeus and Ursus ingressus), did not survive after about 25,000 years ago, while others are still extant, such as brown bear (Ursus arctos). Our article aims at a better understanding of the palaeoecology of these large “carnivores” and focuses on two regions, the Ach valley in the Swabian Jura (SW-Germany) with Geißenklösterle and Hohle Fels, and the Totes Gebirge (Austria) with Ramesch and Gamssulzen caves. Both regions revealed two genetically distinct cave bear lineages, and previous studies suggest behavioural differences for the respective bears in these two regions. In the Ach valley, irrespective of the cave site, U. s. spelaeus was replaced by U. ingressus around 28 ka uncal BP with limited chronological overlap without recognizable dietary changes as documented by the isotopic composition (13C, 15N) of the bones. Furthermore, the present study shows that the dental microwear pattern was similar for all bears in both caves, however with a larger variability in Geißenklösterle than in Hohle Fels. In contrast, the two Austrian caves, Gamssulzen (U. ingressus) and Ramesch (Ursus s. eremus), show considerable differences in both palaeodietary indicators, i.e., stable isotopes, and dental microwear, over at least 15,000 years. The oxygen and carbon analysis of the tooth enamel combined with the dental microwear of the same molars provide an extremely diversified picture of the feeding behaviour of these fossil bears. The already known differences between these two study areas are confirmed and refined using the new approaches. Moreover, the differences between the two cave bear lineages in the Totes Gebirge became even larger. Some niche partitioning between both types of cave bears was supported by the present study but it does not seem to be triggered by climate. This multi-disciplinary approach gives new insights into the palaeobiology of extinct bears.
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Post by brobear on Jan 21, 2018 2:42:03 GMT -5
www.livescience.com/7622-huge-cave-bears-disappeared.html Enormous cave bears that once inhabited Europe were the first of the mega-mammals to die out, going extinct around 13 millennia earlier than was previously thought, according to a new estimate. Why'd they go? In part because they were vegetarians. The new extinction date, 27,800 years ago, coincides with a period of significant climate change, known as the Last Glacial Maximum, when a marked cooling in temperature resulted in a reduction or total loss of the vegetation that the cave bears ate (today’s brown bears are omnivores). The loss of this food supply led to the extinction of the cave bear, Ursus spelaeus, one of a group of "megafauna" — including the woolly mammoth, woolly rhinoceros, giant deer and cave lion — to disappear during the last Ice Age, the researchers wrote in a research paper published online Nov. 26 in the journal Boreas. Mysterious disappearance Over the years, numerous cave bear remains have been discovered in caves where the animals probably died during winter hibernation. Cave bears were huge, with males growing up to around 2,200 pounds (1,000 kg). The maximum recorded weight of both Kodiak bears and polar bears — the largest bears living today — is 1,760 pounds (800 kg), with averages of around 1,100 pounds (500 kg). During the Middle Ages, the bones of cave bears, thought to be the remains of dragons, were collected and used for medicine, the researchers say. The question of what caused cave bears, woolly mammoths and the other large mammals to go extinct has been a mystery. Some researchers think humans hunted the mega-mammals to extinction, but researcher Martina Pacher of the University of Vienna and her colleague Anthony J. Stuart of the Natural History Museum, London, found no convincing evidence for this idea regarding cave bears. Another theory is that some virus or bacteria could have sickened populations of mega-mammals, but Pacher and Stuart think such a "hyperdisease" is unlikely to explain the timing of the extinctions or the fact that body sizes of the dying-out animals varied so much. 'One of the earliest to disappear' Pacher used new data and existing records of radiocarbon dating on cave bear remains to construct the new chronology for cave bear extinction that supports the climate change scenario. "Our work shows that the cave bear, among the megafauna that became extinct during the Last Glacial period in Europe, was one of the earliest to disappear," Pacher said. "Other, later extinctions happened at different times within the last 15,000 years." Many scientists previously claimed that cave bears survived until at least 15,000 years ago, but the methodology of these earlier studies included errors in dating as well as confusion between cave bear and brown bear remains, Pacher and Stuart say, so they excluded those data from the analysis. Pacher and Stuart also concluded, from evidence on skull anatomy, bone collagen and teeth, that these extinct mammals were predominantly vegetarian, eating a specialized diet of high-quality plants. Compared with other megafaunal species that would also become extinct, the cave bear had a relatively restricted geographical range, being confined to Europe (ranging from Spain to the Ural Mountains in Russia), which may offer an explanation as to why it died out so much earlier than the rest. "Its highly specialized mode of life, especially a diet of high-quality plants, and its restricted distribution left it vulnerable to extinction as the climate cooled and its food source diminished," Pacher said. Why did the brown bear survive? The brown bear, with which Ursus spelaeus shares a common ancestor, was spread throughout Europe and much of northern Asia and has survived to the present day. "A fundamental question to be answered by future research is: why did the brown bear survive to the present day, while the cave bear did not?" Stuart said. Answers to this question may involve different dietary preferences, hibernation strategies, geographical ranges, habitat preferences and perhaps predation by humans. Despite more than 200 years of scientific study — beginning in 1794 when anatomist Johann Rosenmüller first described bones from the Zoolithenhöhle in Bavaria as belonging to a new extinct species, which he called cave bear — the timing and cause of its extinction remain controversial. The research was funded by Natural Environment Research Council UK, the Cultural Grant of Lower Austria and the EU project: AlpiNet Culture 2000.
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Post by brobear on Jan 21, 2018 2:45:09 GMT -5
Above extinction theory sounds plausible, except that while Ursus speleaus speleaus was a vegetarian, the other subspecies, Ursus speleaus ingressus was an omnivore that was highly carnivorous.
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Post by tom on Jan 21, 2018 10:39:44 GMT -5
Above extinction theory sounds plausible, except that while Ursus speleaus speleaus was a vegetarian, the other subspecies, Ursus speleaus ingressus was an omnivore that was highly carnivorous. Ursus speleaus speleaus (Giant Cave Bear) must have been a sight to see. With a maximum weight for big males running 2200 lbs he must have stood 11 ft or possibly more on his hind legs. What a monster he must have been. Hard to believe such a beast being a vegetarian....
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Post by tom on Jan 21, 2018 10:56:42 GMT -5
You can see by this comparison that he was a behemoth.
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Post by tom on Jan 21, 2018 10:58:19 GMT -5
More comparisons.
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Post by brobear on Jan 21, 2018 13:21:42 GMT -5
www.researchgate.net/publication/233639688_The_type_specimen_of_Ursus_priscus_GOLDFUSS_1818_and_the_uncertain_status_of_Late_Pleistocene_brown_bears carnivoraforum.com/topic/30156737/1/ Steppe brown bear Ursus arctos priscus Goldfuss, 1818 – huge scavenger of Late Pleistocene grasslands paleocommunities Adrian Marciszak1 – Charles Schouwenbourg2 – Grzegorz Lipecki3 – Wiktoria Gornig1 – Vlastislav Káňa4 – Martina Roblíčková4 1 Department of Paleozoology, Institute of Environmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland; adrian.marciszak@uwr.edu.pl, wiktoria.gornig@uwr.edu.pl 2 Dorpsstraat 53, 3238BB Zwartewaal, Netherlands; c.schouwenburg@upcmail.nl 3 Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Sławkowska 17, 31-016 Kraków, Poland; lipecki@isez.pan.krakow.pl 4 Moravian Museum, Anthropos Institute, Zelný trh 6, 659 37 Brno, Czech Republic; mroblickova@mzm.cz, kanabat@email.cz With opportunistic behaviour, extremely broad diet, ability to adapt to various habitats ranging from semi-deserts to Arctic tundra, including arid and mountain areas, Ursus arctos could adapt to the changes of environmental conditions. The brown bear remains from many European sites document the occurrence of a very particular kind of bear. This giant bear, called steppe brown bear Ursus arctos priscus, was a rare but permanent member of open grasslands mammal palaeocommunities. It is very characteristic that this form is always strangely difficult to find not only in open sites but also in caves. Compared to other carnivores, the steppe brown bear was never common in one locality and tended to be a solitary hunter and scavenger, which required large expanses of open grassland. This bear was a scavenger and kleptopa - rasit, whose huge size gave it advantage over other predators (also ancient hunters) (Fig. 1). It also followed herds of herbivores and took animals which died naturally or in another way. Occasionally it also hunted. In its behaviour, it resembled the modern Ursus maritimus or Arctodus simus from North America in the past. It can be conjectured that, except pregnant females, the steppe brown bear was active year-round following herbivores and other carnivores in search of food. Isotopic analysis shows that brown bears were highly carnivorous till the late glacial and became more omnivorous with the change of climate and environmental conditions. The last postglacial warming brought about a shrinkage of open grasslands, disappearance of ungulate herds and expansion of forests. The largest species like mammoths, rhinoceros, and some bovids became entirely extinct, other forms lived in smaller herds or small groups, and carcasses were much harder to obtain than previously. The density was much lower, and the amount of available food much smaller. There was not enough food and space for such a huge bear. During the postglacial times, the brown bear slowly dwarfed, and also smaller bears similar to the nominate subspecies entered from the south and southeast. The dwarfing process, however, was not the same in entire Europe, since in some regions large, robust bears of priscus-type survived longer. The form is only a smaller descendant of the Late Pleistocene form, which occurred till the early Holocene over the coast of the North and Baltic Seas as well as in some parts of Germany and Poland. Some populations slowly retreated to the northeast, while others were genetically swamped by the modern European bear. Finally, in the early Holocene, the modern brown bear appeared and became the sole bear species in Europe. What in fact was the steppe brown bear Ursus arctos priscus Goldfuss, 1818? Adrian Marciszak1 – Charles Schouwenbourg2 – Wiktoria Gornig1 1 Department of Paleozoology, Institute of Environmental Biology, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland; adrian.marciszak@uwr.edu.pl, wiktoria.gornig@uwr.edu.pl 2 Dorpsstraat 53, 3238BB Zwartewaal, Netherlands; c.schouwenburg@upcmail.nl Steppe brown bear Ursus arctos priscus is a very particular kind of bear. This giant arctoid bear (Fig. 1), was a rare but permanent member of open grasslands mammal palaeocommunities. Described almost two centuries ago, till recent there are no sharply defined metrical and morphological features characterising this form. Many authors proposed in the past factors like great size, robust build, massive metapodials and a significant amount of speleoid features in morphology, especially dentition. But till new, partially because not a sufficient number of specimens, partially because of the enormous variability of the brown bear as a species. Obtained so far by us data showed that genetic analysis is no answer, what in fact is steppe brown bear. Our metrical and morphological analysis revealed that it is an example of the plasticity of Ursus arctos and answer of the species for the availability of the large amount of meat in open grasslands in steppetundra. It should be considered as a different chronoform/ecomorph, which features like immense posture and broad teeth are an expression of specialisation to scavenge. Moreover, the bear remains in somewhat older faunal assemblages, often coexisted with thermophile species such as Palaeoloxodon antiquus or Stephanorhinus kirchbergensis, might indicate the presence of another form, closely related to the steppe brown bear. The Taubach bear Ursus arctos taubachensis Rode, 1935, which appeared already in the late Middle Pleistocene, is a characteristic component of European interglacial faunas like Taubach, Weimar Ehringsdorf, Kent’s Cavern or Tornewton Cave (Kurtén, 1957). Sometimes synonymised with Ursus arctos priscus, it differs nevertheless in some metric and morphological features (Baryshnikov, 2007), which points to a distinct form (Marciszak et al., 2017). The problem needs further adna analysis, which may resolve the presence of other bear forms in Silesian open sites.
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Post by brobear on Jan 22, 2018 6:25:31 GMT -5
Tom; your comparisons was actually an incredible find. It led me in a search for information on Ursus arctos priscus, which is new to me. Tigerluver had told me of the huge grizzlies of Pleistocene Europe. I have been seeking info for a long time now - Thankx. The post above I also posted on "Pleistocene Grizzly".
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Post by brobear on Apr 1, 2018 19:10:56 GMT -5
shaggygod.proboards.com/ True causes for extinction of cave bear revealed. The cave bear started to become extinct in Europe 24,000 years ago, but until now the cause was unknown. An international team of scientists has analysed mitochondrial DNA sequences from 17 new fossil samples, and compared these with the modern brown bear. The results show that the decline of the cave bear started 50,000 years ago, and was caused more by human expansion than by climate change. "The decline in the genetic diversity of the cave bear (Ursus spelaeus) began around 50,000 years ago, much earlier than previously suggested, at a time when no major climate change was taking place, but which does coincide with the start of human expansion", Aurora Grandal-D'Anglade, co-author of the study and a researcher at the University Institute of Geology of the University of Coruña, tells SINC. According to the research study, published in the journal Molecular Biology and Evolution, radiocarbon dating of the fossil remains shows that the cave bear ceased to be abundant in Central Europe around 35,000 years ago. "This can be attributed to increasing human expansion and the resulting competition between humans and bears for land and shelter", explains the scientist, who links this with the scarce fossil representation of the bear's prey in the abundant fossil record of this species. In order to reach their conclusions, the team of scientists, led by the Max Planck Institute for Evolutionary Anthropology (Germany) studied mitochondrial DNA sequences from bear fossils in European deposits (Siberia, Ukraine, Central Europe and the Iberian Peninsula, specifically Galicia), and carried out a Bayesian analysis (of statistical probability). The scientists also made comparisons with the modern brown bear (Ursus arctos) and with fossil samples of this species of bear, and managed to show why one became extinct and the other did not. In order to demonstrate this, the study analysed 59 cave bear DNA sequences and 40 from the brown bear, from between 60,000 and 24,000 years ago for the cave bear and from 80,000 years ago up to the present day for the brown bear. Decline of the caves, extinction of the bears The impoverishment of ecosystems during the last glacial maximum was "the 'coup de grace' for this species, which was already in rapid decline", the author explains. The present day brown bear did not suffer the same fate and has survived until today for one simple reason – brown bears did not depend so heavily on the cave habitat, which was becoming degraded, and this is why they did not follow the same pattern as the cave bears. "Brown bears rely on less specific shelters for hibernation. In fact, their fossil remains are not very numerous in cave deposits", the Galician researcher says. The definitive extinction of the cave bear "broadly" coincides with the last cooling of the climate during the Pleistocene (between 25,000 and 18,000 years ago), which may have led to a reduction in shelter and the vegetation that the animals fed on. The cave bear inhabited Europe during the Late Pleistocene and became definitively extinct around 24,000 years ago, although it held out for a few thousand years longer in some areas, such as the north west of the Iberian Peninsula, than in other places. This ursid was a large animal, weighing 500 kg on average, and was largely a herbivore. The bear hibernated in the depths of limestone caves, where the remains of individuals that died during hibernation slowly accumulated over time. ### References: Stiller, Mathias; Baryshnikov, Gennady; Bocherens, Herve; Grandal D'Anglade, Aurora; Hilpert, Brigitte; Muenzel, Susanne C.; Pinhasi, Ron; Rabeder, Gernot; Rosendahl, Wilfried; Trinkaus, Erik; Hofreiter, Michael; Knapp, Michael. "Withering Away-25,000 Years of Genetic Decline Preceded Cave Bear Extinction" Molecular Biology and Evolution 27(5): 975-978, mayo de 2010. doi:10.1093/molbev/msq083 www.eurekalert.org/pub_releases/2010-08/f-sf-tcf082410.php
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Post by brobear on Apr 1, 2018 19:13:00 GMT -5
From Cave Bear Ecology and Interactions with Pleistocene Humans: shaggygod.proboards.com/Abstract Human ancestors (Homo spp.), cave bears (Ursus deningeri, U. spelaeus), and brown bears (U. arctos) have coexisted in Eurasia for at least one million years, and bear remains and Paleolithic artifacts frequently are found in the same caves. The prevalence of cave bear bones in some sites is especially striking, as these bears were exceptionally large relative to archaic humans. Do artifact-bear associations in cave deposits indicate predation on cave bears by early human hunters, or do they testify simply to early humans' and cave bears' common interest in natural shelters, occupied on different schedules? Answering these and other questions about the circumstances of human-cave bear associations is made possible in part by expectations developed from research on modern bear ecology, time-scaled for paleontologic and archaeologic applications. Here I review available knowledge on Paleolithic human-bear relations with a special focus on cave bears (Middle Pleistocene U. deningeri) from Yarimburgaz Cave, Turkey. Multiple lines of evidence show that cave bear and human use of caves were temporally independent events; the apparent spatial associations between human artifacts and cave bear bones are explained principally by slow sedimentation rates relative to the pace of biogenic accumulation and bears' bed preparation habits. Hibernation-linked behaviors and population characteristics of cave bears, based on osteometric, isotopic, and age and sex structure analyses, indicate that they depended heavily on seasonal food supplies, which were rich in resistant plant materials and cryptic, gritty foods. There is little evidence of direct ecological interaction among Pleistocene humans and cave bears. PDF LINK:
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Post by brobear on Apr 1, 2018 19:15:05 GMT -5
Cave Bear Body Mass: shaggygod.proboards.com/Per Christiansen's 1999 paper on A.simus & Cave bear body mass: What size were Arctodus simus and Ursus spelaeus (Carnivora: Ursidae)? Abstract Body masses of the giant short-faced bear (Arctodus simus Cope) and the cave bear (Ursus spelaeus Rosenmueller & Heinroth) were calculated with equations based on a long-bone dimensions:body mass proportion ratio in extant carnivores. Despite its more long-limbed, gracile and felid-like anatomy as compared with large extant ursids, large Arctodus specimens considerably exceeded even the largest extant ursids in mass. Large males weighed around 700-800 kg, and on rare occasions may have approached, or even exceeded one tonne. Ursus spelaeus is comparable in size to the largest extant ursids; large males weighed 400-500 kg, females 225-250 kg. Suggestions that large cave bears could reach weights of one tonne are not supported. Free PDF LINK: www.sekj.org/PDF/anzf36/anzf36-093p.pdf
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Post by King Kodiak on Aug 16, 2019 5:00:57 GMT -5
Humans pushed cave bears to extinction, their DNA suggests August 15, 2019 at 9:00 AM EDT Cave bears, Ursus spelaeus, must have made magnificent impressions on the Neanderthals and modern humans who encountered them. The animals, burly and broad-shouldered, lumbered all over Europe. True to their name, they slept and wintered in caves, emerging each spring to blink awake in the Pleistocene sunlight. The biggest cave bears grew to 2,000 pounds, hundreds of pounds larger than the largest brown bears alive today. Now the bears’ bones are scattered in the caves they once occupied. They went extinct around 20,000 years ago. What killed off the bears is a question that’s gotten a lot of attention from scientists. For one thing, they have lots of bear fossils to examine. What’s more, the cave bears were closely related to brown bears — yet they met very different fates. A study published Thursday in the journal Scientific Reports will not put the question totally to rest. But the genetic data wrung from cave bear bones make a compelling case that humans played a large role in their extinction. “It’s a very nice study” that shows something “quite profound happened to the global cave bear population around 40,000 years ago,” said Axel Barlow, a biologist at the University of Potsdam, in Germany, who was not involved with this research. Last year, Barlow and his colleagues showed that living brown bears contain DNA from cave bears, which means the two species mated, just as humans and Neanderthals did. Cave bears split from the brown bear lineage around 1.2 million years ago. The authors of the new study examined mitochondrial DNA from 130 bears. Mitochondria provide a cell with energy; in bears as in humans, mitochondria and their DNA are inherited only from mom through the egg cell. Subtle differences in this genetic material allowed the scientists to calculate the numbers of female bears in during the species’s final years on the planet. “Based on the diversity and the radiocarbon dates of the mitochondrial genomes, you can model the effective female population size through time,” said study author Verena Schünemann, a professor of paleogenetics at the University of Zurich. This bear population remained stable from 200,000 to 50,000 years ago. At around 40,000 years, it began to crash. Twenty thousand years later, cave bears vanished. Some researchers have proposed that climate change felled the bears. Ice sheets advanced and shrank during the Pleistocene Epoch, the period from 2.6 million to 11,700 years ago. Wear on the bears’ teeth suggests the animals mostly ate plants. (Though more recent discoveries of tooth marks on bear bones suggests they ate the bodies of other cave bears.) If vegetation shifted with the ice cycles, perhaps the bears struggled with smaller food supplies. But, the study authors note, in Europe between 200,000 to 50,000 years ago, the climate cooled and warmed twice without any apparent impact on the bears. Or, as study author and University of Tubingen paleobiologist Hervé Bocherens put it, “Cave bear populations did not show significant fluctuations during climatic oscillations before 50,000 years ago.” Instead, the drastic population decline began at the same time as the arrival of modern humans in Europe. “We can’t rewind the clock, taking humans out of the picture, and see whether the cave bears survived or not,” Barlow said. “The emerging picture for cave bears, shown by not only this study but also decades of careful research, is that the influx of anatomically modern humans in Europe matches very well — both in timing and geographically — with the decline in cave bear.” Physical evidence shows humans killed the bears. More than a decade ago, paleontologists discovered the tip of a flint weapon embedded in a cave bear’s spine. More recently, a group of scientists in Italy, studying butcher marks on bear bones, suggested that Neanderthals hunted the animals when they were most vulnerable — as the animals awoke from spring hibernation. “They probably killed cave bears for the same reasons that they killed other large mammals,” Bocherens said, meaning for their skins and meat. Cave bears returned to the caves where they were born, Schünemann said. As human populations grew, requiring more shelter for longer periods of time, humans may have ejected the bears from their birth caves. Schünemann would not totally absolve climate change. There “might be still a synergistic effect of both factors: humans and climate,” she said. It may be that humans applied pressure to the bears as climate caused their population to fragment and food supplies diminish. Cave bears, mammoths, giant sloths and other megaherbivores of ages past were, in the lingo of biologists, ecosystem engineers. As they chowed, pooped and stomped, these animals spread plants and recycled nutrients. The grassy steppes woolly mammoths once tended have collapsed into tundra and Arctic desert. Giant sloths once spread avocado seeds across South America. Cave bears brought great amounts of organic material into caverns, something no living European creature can do. If humans helped destroy the bears, then the animals join a list of creatures we deemed too tasty, too annoying, too docile — too anything — to live. Only in the last sliver of human history have we begun defending rare species through efforts like the Endangered Species Act, which the Trump administration recently moved to weaken. “Looking at the impact of climate change and human impact on large mammals can tell us a lot about the general process and consequences of large mammal extinction,” Bocherens said. “Studying the past to save the future: This is what we try to do.” beta.washingtonpost.com/science/2019/08/15/humans-pushed-cave-bears-extinction-their-dna-suggests/?outputType=amp
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Post by brobear on Apr 1, 2020 19:01:24 GMT -5
phys.org/news/2020-04-evolutionary-cave-hibernate-extinction.html?fbclid=IwAR2298QKxeTcAbJumL1tErJVyanLJvoK0cCIg5Ynjn-0zO8iqFp_3UmN7C4 Evolutionary adaptation helped cave bears hibernate, but may have caused extinction. A study published in Science Advances on April 1 reveals a new hypothesis that may explain why European cave bears went extinct during past climate change periods. The research was motivated by controversy in the scientific literature as to what the animal (Ursus spelaeus) ate and how that affected their demise. The new hypothesis emerged, in part, from computational analysis and computer biting simulations conducted in the laboratory of Jack Tseng, Ph.D., assistant professor of pathology and anatomical sciences in the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo. Tseng is a co-author on the paper with corresponding authors Borja Figueirido, Ph.D., and Alejandro Pérez-Ramos, Ph.D., his doctoral student and first author, both of the Departamento de Ecologia y Geologia of the Universidad de Malaga, Spain. *Read More....
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Post by King Kodiak on Apr 3, 2020 12:15:29 GMT -5
Europe’s cave bears may have died out because of their large sinuses The huge cave bears that once roamed Europe may have gone extinct because their large sinuses made it difficult to adapt their diet during a severe cold snap. Cave bears (Ursus spelaeus), which weighed up to 1000 kilograms and had a plant-based diet, went extinct 24,000 years ago when temperatures plummeted during the last glacial maximum. Scientists have speculated that the bears died out because the colder climate depleted food availability or they were driven to extinction by prehistoric humans. But one mystery is why closely related brown bears (Ursus arctos) managed to survive the same conditions. Alejandro Pérez-Ramos at the University of Malaga in Spain and his colleagues took CT scans of the skulls of four extinct cave bears and eight living bear species, including brown bears, and used them to create computer simulations of the bears’ different chewing styles. They found that cave bears had large sinuses that shaped their skulls in such a way that they could only chew with their back teeth. The researchers argue that this may explain why cave bears went extinct when the climate cooled and plant food ran low, because they couldn’t switch to eating meat, which normally requires the use of the front teeth. Compared to cave bears, brown bears had smaller sinuses and greater skull flexibility for chewing with their front or back teeth. This may be why they survived: they could eat plants or meat, says Pérez-Ramos. Fatal trade-off So why did cave bears evolve large sinuses in the first place? They may have helped the bears hibernate for longer, which would have carried advantages as winters started to stretch out during the last glacial period, says Pérez-Ramos. Sinuses are hollow cavities inside the head that act as reservoirs for gases like nitric oxide and hydrogen sulphide, which activate hibernation in some bears by lowering their heart rate and body temperature. However, being constrained to a plant-based diet meant the bears probably couldn’t fatten themselves up enough to survive the increasingly long and extreme winters, and may have starved to death as they hibernated, says Pérez-Ramos. In other words, the development of large sinuses may have been a “fatal trade-off”, he says. Journal reference: Science Advances, DOI: 10.1126/sciadv.aay9462 www.newscientist.com/article/2239316-europes-cave-bears-may-have-died-out-because-of-their-large-sinuses/
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Post by OldGreenGrolar on Jun 21, 2020 7:49:52 GMT -5
Beware of humans and glacial maximums – the story of cave bear extinction .
We found indications that humans may have had a major impact on the extinction of cave bears in Europe during the last ice age. In our study, we found a drastic decline of cave bear populations starting around 40,000 years ago based on 59 newly reconstructed mitochondrial genomes of cave bears from the Late Pleistocene. The cave bear is one of the dozens of species of large Pleistocene mammals that faced extinction during the last Ice Age. Until today, the reasons for their extinctions remain mysterious, especially since the cave bear Ursus spelaeus populated vast areas of Eurasia for more than 200,000 years. With an average weight of up to 600 kilograms, a shoulder height of 1.7, and a length of up to 3.5 meters, they surpassed all modern bear species in size. However, despite their fearsome stature, the bears were pure vegetarians, according to dietary isotopic studies. To answer if climate change or the spread of modern humans caused their disappearance, our international team of paleogeneticists, archaeozoologists, and palaeontologists investigated the phylogeography and demography of the cave bear across Europe during the last 50,000 years. We sampled 78 cave bear bones from 14 archaeological sites, in detail from Switzerland, Poland, France, Spain, Germany, Italy, and Serbia. In total, we reconstructed 59 cave bear mitochondrial genomes and compared these genomes to 64 previously published mitochondrial genomes to find out more about the different cave bear populations that lived in Europe during the Late Pleistocene. We wanted to trace potential migrations of these populations as well as study their genetic diversity present at different periods. We detected five major mitochondrial DNA lineages, of which two were newly defined with the novel mitochondrial genomes from this study, suggesting a larger diversity than previously assumed. We characterized these new lineages of the eastern cave bear Ursus ingressus by specimens originating in south-eastern Europe - mainly Serbia, but also western Europe - namely France. So far, it was assumed that Ursus ingressus did not cross the Rhine River and only expanded to western Europe roughly 30,000 years ago. The presence of these bears in eastern France already more than 10,000 years earlier demonstrates that their migration in Europe was more entangled than a simple westward expansion from their eastern habitats. Furthermore, we estimated that the lineages originated from a common ancestor, which was widespread in Europe approximately 451,000 years ago, underlining the new, more complex cave bear distribution. To explore this, we modeled the cave bear population size across time based on the newly reconstructed mitochondrial genomes as well as published ones. According to these models, the cave bear populations faced a dramatic decline around 40,000 years ago after a long relatively stable period, which also included two cold periods. The time setting of this decline coincides with the arrival of anatomically modern humans in Europe, while the maximum of the last ice age started around 10,000 years later. Therefore, humans may have played a key role in the cave bear extinction via other factors such as hunting. During the Maximum of the last ice age, likely only small residual populations of cave bears survived in isolated refuges, as suggested by the low genetic diversity at this time. Probably factors like the lack of connectivity between sub-populations, the fragmentation of their habitat, and the impact of humans entering the scene may have all contributed to the final extinction of cave bears around 23,000 years ago. Although human impact and climate change likely had synergistic effects on the cave bear population, the results of the study suggest modern humans had a major role in the extinction of cave bears. However, to better understand the process of their population decline and the movements and relationships of different cave bear groups, nuclear DNA studies are needed to provide more insightful information about the origin and demise of the European cave bear. Original Article: Gretzinger J, Molak M, Reiter E et al. Large-scale mitogenomic analysis of the phylogeography of the Late Pleistocene cave bear. Sci Rep. 2019;9(1). thesciencebreaker.org/breaks/evolution-behaviour/beware-of-humans-and-glacial-maximums-the-story-of-cave-bear-extinction
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