AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Do grizzly bears hibernate in a cave1/22/2024 ![]() ![]() ![]() However, a recent study showed that both species had some hybridization between them. The divergence date estimate of cave bears and brown bears is about 1.2–1.4 Mya. Both show that the cave bear was more closely related to the brown bear and polar bear than it was to the American black bear, but had split from the brown bear lineage before the distinct eastern and western brown bear lineages diversified, and before the split of brown bears and polar bears. This study confirmed and built on results from a previous study using mitochondrial DNA extracted from cave bear remains ranging from 20,000 to 130,000 years old. Sequencing the DNA directly (rather than first replicating it with the polymerase chain reaction), the scientists recovered 21 cave bear genes from remains that did not yield significant amounts of DNA with traditional techniques. The procedure used genomic DNA extracted from one of the animal's teeth. In 2005, scientists recovered and sequenced the nuclear DNA of a cave bear that lived between 42,000 and 44,000 years ago. This allowed the cave bear to gain more energy for hibernation, while eating less than its ancestors. This phenomenon, called molarization, improved the mastication capacities of the molars, facilitating the processing of tough vegetation. The last remaining premolar became conjugated with the true molars, enlarging the crown and granting it more cusps and cutting borders. In a fourth of the skulls found in the Conturines, the third premolar is still present, while more derived specimens elsewhere lack it. The three anterior premolars were gradually reduced, then disappeared, possibly in response to a largely vegetarian diet. Ĭave bears found anywhere will vary in age, thus facilitating investigations into evolutionary trends. ![]() Ursus spelaeus deningeroides, while other authorities consider both taxa to be chronological variants of the same species. The transition between Deninger's bear and the cave bear is given as the last interglacial, although the boundary between these forms is arbitrary, and intermediate or transitional taxa have been proposed, e.g. The immediate precursor of the cave bear was probably Ursus deningeri (Deninger's bear), a species restricted to Pleistocene Europe about 1.8 Mya to 100,000 years ago. The last common ancestor of cave bears and brown bears lived between 1.2–1.4 Mya. In 2021, Akaki Tsereteli State University's students and a lecturer discovered two complete cave bear skulls, with molars, canines, humerus, three vertebrae and other bones, in a previously unexplored cave.īoth the cave bear and the brown bear are thought to be descended from the Plio-Pleistocene Etruscan bear ( Ursus etruscus) that lived about 5.3 Mya to 100,000 years ago. Ĭave bear bones are found in several caves in the country of Georgia. In Romania, in a cave called Bears' Cave, 140 cave bear skeletons were discovered in 1983. A complete skeleton, five complete skulls, and 18 other bones were found inside Kletno Bear Cave, in 1966 in Poland. Many caves in Central Europe have skeletons of cave bears inside, such as the Heinrichshöhle in Hemer and the Dechenhöhle in Iserlohn, Germany. When the "dragon caves" in Austria’s Styria region were exploited for this purpose, only the skulls and leg bones were kept. During World War I, with the scarcity of phosphate dung, earth from the caves where cave bear bones occurred was used as a source of phosphates. The bones were so numerous that most researchers had little regard for them. Twenty years later, Johann Christian Rosenmüller, an anatomist at Leipzig University, gave the species its binomial name. While scientists at the time considered that the skeletons could belong to apes, canids, felids, or even dragons or unicorns, Esper postulated that they actually belonged to polar bears. Taxonomy Rearing Ursus spelaeus skeleton AMNHĬave bear skeletons were first described in 1774 by Johann Friedrich Esper, in his book Newly Discovered Zoolites of Unknown Four Footed Animals. It is thought to have been largely herbivorous. This reflects the views of experts that cave bears may have spent more time in caves than the brown bear, which uses caves only for hibernation. The cave bear ( Ursus spelaeus) is a prehistoric species of bear that lived in Europe and Asia during the Pleistocene and became extinct about 24,000 years ago during the Last Glacial Maximum.īoth the word cave and the scientific name spelaeus are used because fossils of this species were mostly found in caves. ![]()
0 Comments
Read More
Leave a Reply. |