Its fossils belong to one of the most significant Middle Pleistocene faunas in the United States. The site, known as Port Kennedy Bone Cave or just Port Kennedy Cave, was found in the 1870s and explored through the 1890s, but became inaccessible and then buried and forgotten until relocated in the 2000s. Today, within the National Park Service's Valley Forge National Historical Park, there is buried an ancient fissure into which various mammals, birds, reptiles, insects, and plant fragments fell during the Middle Pleistocene. When the Continental Army spent the winter of 1777–1778 at Valley Forge in eastern Pennsylvania, they had no way of knowing they were practically on top of one of the richest fossil sites in eastern North America. National Park Service, Geologic Resources Division. Port Kennedy Bone CaveĪrticle by Justin Tweet Guest Scientist. Photo by Justin Tweet, used with permission of Ted Daeschler/Academy of Natural Sciences of Drexel University. It was found at Port Kennedy Bone Cave and is in the collections of the Academy of Natural Sciences of Drexel University (ANSP 85). It is omnivorous and the size of a black bear.The type specimen of the short-faced bear Ursus haplodon, now considered a synonym of Arctodus pristinus. The only living relative of the short-faced bears is the spectacled bear (Tremarctos ornatus) of South America. It may have died out due to competition with a large Pleistocene subspecies of black bear (Ursus americanus amplidens) and due to brown/grizzly bears (Ursus arctos) invading from the west near the end of the Ice Age. This smaller bear with its longer face and smaller teeth may have been more omnivorous. Their disappearance is linked to changes in habitat that led to the disappearance of some of these large herbivores at the end of the Ice Age.Ī close relative, the lesser short-faced bear (Arctodus pristinus) lived near the Atlantic coast and in Mexico. They probably scavenged and preyed upon large herbivores such as bison, muskoxen, deer, caribou, horses, and ground sloths. Giant short-faced bears lived in Minnesota and the open country west of the Mississippi River and north to Yukon and Alaska. Everything considered, paleobiologists conclude that the giant short-faced bear ate only meat. Tests of bone samples show a very high ratio of nitrogen-15 to nitrogen-14, a nitrogen “signature” that indicates a true carnivore. ![]() The large width of the jaws in relation to their shortness, plus the huge insertions for biting muscles, gave this bear a vise-like killing bite and the ability to crush bones to obtain marrow. ![]() Its short, broad snout had a huge nasal passage, which probably means it had a keen sense of smell and could inhale great volumes of oxygen while pursuing prey. ![]() Its eye sockets are set wide apart and face forward, giving it excellent vision. Its skull and shearing type of teeth indicate a highly carnivorous way of life. It probably could run over 40 miles per hour despite weighing over 1500 pounds. Unlike pigeon-toed modern bears, its toes pointed straight forward, enabling it to walk with a fast, purposeful gait. Rangier and longer legged than any bear today, it was about five feet at the shoulders when walking and stood as tall as 12 feet on its hind legs. Also called the bulldog bear, the giant short-faced bear (Arctodus simus) was undoubtedly the fastest running bear that ever lived.
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