|
Bears of the Pleistocene
|
 
Over at "Carnivora" I just scrolled through 49 pages of "extinct animals" profiles twice. I am really surprised that Ursus spelaeus, the giant European cave bear, is missing. Of course, it is entirely possible that even after two attempts I missed it.
Although it is unlikely that they neglected it on purpose, the Cave bear is still an extremely underrated animal.
Same study as post #110 ... http://news.westernu.ca/2016/09/diet-discovery-shifts-thinking-prehistoric-bear/
Diet discovery shifts thinking on prehistoric cave bear SEPTEMBER 21, 2016 BY PAUL MAYNE Newly discovered information into the inflexible diet of one group of prehistoric bears has scientists rethinking how the creatures lived and what caused the large mammals’ extinction some 25,000 years ago. Working with scientists in Japan, Belgium and Germany, Western biologist Keith Hobson used an isotopic composition found in the collagen of the cave bears’ bones to show the large mammals subsisted on a purely vegan diet. In the study, recently published in the Journal of Quaternary Science, the international team proposed this inflexible diet killed off the bears. “It’s almost a paradigm shift to what we were always thinking,” Hobson said. “Now, we have to rethink how they existed on the landscape and, more importantly, why they went extinct. Did they have the wrong strategy all along? Being herbivores were they therefore particularly prone to any kind of climate change? If the weather turned cold, they would not do well, whereas omnivores and carnivores would look for other sources of food. “Because their niche was so specialized, they were vulnerable to such changes. Any animals that feed on only one thing are very vulnerable. That makes sense ecologically.” The Cave Bears of Belgium lived in Europe during the most recent glacial period, approximately 400,000 years ago. With a length of 3.5 metres and a height of 1.7 metres at the shoulder, these bears were noticeably larger than their modern-day relatives. Despite their name, they did not live in caves but only used them for hibernation. Researchers analyzed amino acid in the bone collagen of 10 cave bears skeletons (eight adults, two cubs), five brown bears from Goyet Cave in Belgium and three modern grizzly bears from Alberta. All the cave bears, as well as some brown bears, had the feeding habits of herbivores (plant eaters). Today’s brown bears are omnivores (feeding on both plants and animals) and, depending on the time of year, will devour plants, mushrooms, berries, smaller to larger mammals, fish and insects. Cave bears were a different story. “Similar to today’s giant panda, the cave bears were extremely inflexible in regard to their food,” he said. “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.” Because they were vegan, researchers believe the creatures were slower and less aggressive than one would expect of a large bear. That may have made them more vulnerable to hunters. “This adds a whole new dimension to the discussion,” said Hobson, who worked with Hervé Bocherens, a former Western postdoctoral scholar, now a professor in the Department of Geosciences at the University of Tübingen in Germany. “The reliance on a purely vegan diet was a crucial reason for the cave bear’s extinction,” Bocherens said. “We now intend to examine additional cave bear bones from various European locations with this new method, as well as conduct controlled feeding experiments with modern bears, in order to further solidify our proposition.” This new interpretation around the extinction of the cave bear has added to a body of evidence as to why some species continue to thrive, while others remain on the brink of extinction. “There are many existing bear species – some more vulnerable than others, such as the polar bear – who have a very specialized diet,” Hobson said. “Understanding what happened to their ancestors in the past, where they may have gone down the wrong way, can help you with modern-day conservation issues, especially now with such a flux in environmental changes. “Are there factors today that could put species at risk for the very same reasons? A specialized diet? Not being able to get out of that niche they are in? What do we do about those ones? So this research does have a modern day equivalent.”
( in my own words )... The giant European cave bear, being strictly a vegetarian ( according to this study - posts #110 and #120 ) was somewhat larger than our modern Kodiak bear. Now, the more protein consumed by a brown bear the bigger the bear. Coastal brown bears eat heavily on protein rich salmon and are thus bigger and heavier than their inland relatives which feed more heavily on vegetation. This makes me wonder just how the science works with the cave bear; him being so huge?
Also interesting... the measurements given on post #20 for the cave bear: 1.7m ( 5 feet 7 inches ) shoulder height and 3.5m ( 11 feet 5 inches ) from nose to rump. (10-01-2016, 04:44 PM)brotherbear Wrote: ( in my own words )... The giant European cave bear, being strictly a vegetarian ( according to this study - posts #110 and #120 ) was somewhat larger than our modern Kodiak bear. Now, the more protein consumed by a brown bear the bigger the bear. Coastal brown bears eat heavily on protein rich salmon and are thus bigger and heavier than their inland relatives which feed more heavily on vegetation. This makes me wonder just how the science works with the cave bear; him being so huge? They were many different species of Cave bears. Ursus spelaeus was even more herbivorous than the Giant Panda, but Ursus ingressus was as omnivorous as the Brown bears. 
Think about it this way, why are the largest animals always herbivores? Even though meat could have more quality, there is no where near as much of it as compared to vegetation. Thus quantity will overwhelming overdo quality in this case. Also, O2 levels were higher back then, which allows greater size due to more efficient aerobic metabolism.
Another myth is that vegetation doesn't offer protein, in modern days you can easily obtain enough proteins from soy, tempeh, beans, seeds, quinoa and so on.
obviously not enough protein for a hypercarnivore but like @tigerluver said, the largest animals have always been herbivores. Abundance and nutrients would be my reasoning as to why.
The Pleistocene vegetation might offer more protein than the one we currently have.
More or less, the herbivorous Cave bears and the omnivorous Cave bears were about the same size.
http://news.nationalgeographic.com/news/2005/06/0606_050606_alpsbears_2.html
Ancient Bear DNA Mapped -- A 1st for Extinct Species The researchers sequenced all of the genomic DNA they could get out of the cave bear bones. Without amplifying any of it, they then identified each sequence by comparing it to the complete dog-genome sequence that is publicly available. Dogs and bears, which diverged some 50 million years ago, are 92 percent similar on the sequence level. "[It was] sort of like looking for a needle in a haystack," said Eddy Rubin, the director of the U.S. Department of Energy's Joint Genome Institute in Walnut Creek, California, where the work was done. "Fortunately the computer was a great magnet for finding the needles we were interested in." About 6 percent of the sample that was sequenced yielded undamaged cave bear DNA, while the rest was a hodgepodge of microbial contaminants. Within those fractions of cave bear DNA were bits of genes. Comparing the ancient bear sequences with those of modern bears, the scientists showed that cave bears were more closely related to brown bears than to black bears. "It shows that we got enough ancient genomic DNA to learn something biologically relevant about the cave bear," Noonan said. Human Evolution The cave bear DNA sequencing opens the door to the testing of other extinct species, including our nearest prehistoric relatives, the Neandertals. The scientists say they plan to sequence the Neandertal genome over the next several years. Another possibility is to apply these techniques to the remains of Homo floresiensis, found recently in Indonesia. Researchers nicknamed this human ancestor "the hobbit" because of its tiny stature. H. floresiensis is believed to have diverged from modern humans two million years ago. Neandertals may have diverged from humans 500,000 years ago. The successful DNA sequencing of the two human-ancestor species could help scientists describe the evolutionary events that led to modern humans. What about sequencing the DNA from dinosaur fossils? "Unfortunately, we don't think [that] will ever be possible," Noonan said. "DNA does not survive beyond a hundred thousand years under the environmental conditions in which we found our cave bear remains. And of course, dinosaur fossils are at least 65 million years old."
Anything that points us int the direction of the missing links is a huge discovery.
http://www.foxnews.com/story/2008/01/09/prehistoric-cave-bears-werent-so-cuddly-after-all.html
Prehistoric Cave Bears Weren't So Cuddly After All By Charles Q. Choi Published January 09, 2008 Our ancestors had lots of predators and competitors to worry about — saber-toothed cats, dire wolves and even giant man-eating birds of prey. Now you can add cave bears to that list. These prehistoric giants were roughly a third larger than modern grizzly bears. • Click here to visit FOXNews.com's Evolution & Paleontology Center. Previously, scientists thought cave bears were just vegetarians, evoking an image of gentle giants that fed solely on berries and roots. Now bones from the Carpathians — the mountains where Dracula supposedly dwelt — suggest cave bears could have also been carnivores, and possibly even cannibals. Bad to the bone Cave bears (Ursus spelaeus) are named after the places where their bones are commonly found — caves across Europe. They died out roughly 20,000 years ago, when ice dominated the Northern Hemisphere. For the past 30 years, studies of their skulls, jaws and teeth suggested cave bears might have been largely herbivorous. In addition, the bones of central and western European cave bears matched those of vegetarians in having low levels of nitrogen-15, whose atomic nucleus has one more neutron than common nitrogen-14 does. Animals accumulate nitrogen-15 in their bodies, and animals that eat animals — that is, carnivores — build up more nitrogen-15 than herbivores do. Still, black bears and brown bears are omnivores. This suggested that although some cave bears were largely vegetarian, others might have been more carnivorous. New data from the Pestera cu Oase ("Cave with Bones") in the southwestern tip of the Carpathian mountains in Romania now hints most of its cave bears were significantly carnivorous, due to their high nitrogen-15 levels. Hidden caves Retrieving the bones was not easy. "It is a pretty inaccessible cave that you need to go underwater to get to," said researcher Michael Richards, an archaeologist at the Max Planck Institute for Evolutionary Anthropology at Leipzig, Germany. The cave entrances the bears once used collapsed long ago, so one had to reach the bones through a lower level, going through an active spring and an underground river. To reach the Pestera cu Oase, which was discovered by inquisitive Romanian cavers, scuba equipment and climbing gear are necessary. "On a daily basis, you can imagine that it meant a lot of very hard work for my small excavation team, and also that it was not exempt of some risk," said researcher Joao Zilhao, a Paleolithic archaeologist at the University of Bristol in England. Bears vs. humans The findings suggest these cave bears could have struggled over meat with humans and the other carnivores of the time — hyenas, wolves and cave lions — as well as omnivores such as brown bears. "It would be interesting to measure more cave bears from other sites in this region to see if we find other carnivorous cave bears," Richards said. "It would also be interesting trying to determine why these bears were carnivores when other cave bears weren't." The researchers suggest the cave bears might have eaten fish, but another possibility is "some degree of bear-bear cannibalism," said University of Arizona zooarchaeologist Mary Stiner, who did not participate in this study. In brown bears, "cannibalism and eliminating rivals and young go hand in hand, as in lions. This behavior is also clear from very large cave bear tooth marks on young cave bear skulls in Yarimburgaz Cave in western Turkey." These results might also shed light on cave bear bones that humans and Neanderthals apparently placed in these caves in ancient times. These actions "are often interpreted as some sort of ritual or symbolic behavior, and I wonder if cave bears were particularly compelling for humans if they were also a competitor," Richards told LiveScience. The international team of researchers detailed its findings online Jan. 7 in the journal Proceedings of the National Academy of Sciences.
Posts #120 and #128 show the findings of 2 separate scientific studies, one in 2008 and the other in 2016, which produce two very different conclusions. So, what are we to believe?
(10-07-2016, 06:01 PM)brotherbear Wrote: Posts #120 and #128 show the findings of 2 separate scientific studies, one in 2008 and the other in 2016, which produce two very different conclusions. So, what are we to believe? The two respective studies were based on two different species of the Cave bears. The regular Cave bears (Ursus spalaeus) were as herbivorous as the Giant Panda, but those Cave bears (Ursus ingressus) from the Southeast Europe were extremely carnivorous. (10-07-2016, 08:25 PM)GrizzlyClaws Wrote:(10-07-2016, 06:01 PM)brotherbear Wrote: Posts #120 and #128 show the findings of 2 separate scientific studies, one in 2008 and the other in 2016, which produce two very different conclusions. So, what are we to believe? Thank you GrizzlyClaws. That clears things up considerably. |
| Users browsing this thread: |
| 18 Guest(s) |