The Family of Bears (Ursidae) is usually divided into three
Sub-families – Giant Panda (Ailuropodinae),
True Bears (Ursinae), and Short-faced
Bears (Tremarctinae). Today only Spectacled Bear (Tremarctos ornatus) of South America represents
the Short-faced Bear Sub-family. Extinct
members of the Tremarctinae included Arctodus
pristinus (Lesser Short-Faced Bear), Arctodus
simus (Giant Short-faced Bear), and Florida Cave Bear (Tremarctos floridanus).
Although He had a similar lifestyle
to European Cave Bear (Ursus spelaeus),
Florida Cave Bear was not related to Her, since European Cave Bear was a True
Bear. Though large and muscular, He was
a vegetarian who preferred to eat berries instead of meat. As well as dwelling in caves, Florida Cave
Bear also roamed the swamps and valleys of the Southeastern United States.
Meanwhile Arctodus simus and Arctodus
pristinus split off from an earlier Bear Ancestor – Plionarctos, who lived in North America about 10 million years
ago. A.
simus evolved to be the largest carnivore on earth since the Age of the
Dinosaurs. Smaller than A. simus, A. pristinus was still larger than the other Carnivores. Because their snouts were short in proportion
to their heads, these Bears became known as the Short-faced Bears or Bull-dog
Bears. However, these ancient Bears had
the same skull proportions as modern Bears.
When the bones of A. simus were first discovered, her huge
size led many paleontologists to believe that She was the ultimate carnivore. They
reasoned that both A. simus and A. pristinus needed a lot of meat to
survive, and therefore ate it in huge amounts.
However, upon further investigation, various scientists had to revise
their ideas to include the theory that these Bears were probably specialized scavengers.
When various paleontologists
examined the leg bones of these two Short-faced Bears, they realized that these
bones were too long for their large bodies if the Bears were to be active
hunters. Moreover, these Bears’ legs were
not those of a carnivore, since these limbs could not withstand the quick turns
and long periods of running after prey. Thus,
the physical makeup of the Bears’ legs points towards these animals being
scavengers.
Other signs that A. simus and A. pristinus were probably scavengers were the construction of their
nasal cavities, jaws and teeth. To be a
scavenger, an animal needs a keen sense of smell to detect rotting corpses from
long distances. The large nasal cavities
of these Bears provided Them with an acute sense of smell. Meanwhile, the jaws and teeth of these Bears were
designed to crack open bones to get to the nourishing marrow inside.
Short-faced Bears went extinct when
the mega-fauna (Mammoths and others) of the Americas and their predators died
off. Though They were impressive in
their size and scope, Short-faced Bears were specialized scavengers. With the loss of large carcasses, They had
nothing to eat and could not sustain Themselves.
Short-faced Bears demonstrate the
interconnectedness of life. As
scavengers, They ate the leftovers from the kills of the super-predators such
as Saber-toothed Cats. When the large prey animals such as Mammoths died off,
the predators and the specialized scavengers had little to eat. (Only
generalists such as Grizzlies, who could live off on Insects and berries, would
survive.) In this ancient world of
mega-fauna, life seemed abundant, but something happened to cause this
particular thread of life to snap. When
that web of life broke, these large animals became doomed.
When
we recognize our interdependence with others in our lives, we can keep these
webs strong. Because we need many others
in our lives, we must keep these threads alive.
For our own survival, we must preserve the diverse richness of life in our
own environments. When all of us act as one,
the web of life becomes strengthened.
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