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Ancient Bison
The extinct ancient bison (Bison antiquus) was an ancestor of the living North American bison (often called the buffalo). It is the most common of the large herbivores found at Rancho La Brea. A second, rarer species is the long-horned bison. This had a horn core spread of about six feet (1.8 meters). Bison are thought to have come into North America from Asia about 500,000 years ago across a land bridge that connected Alaska with Asia when sea levels were lower.
Not all the animals lived at Rancho La Brea year-round. Some were migratory, traveling in and out of the area. How do scientists know this?
At Rancho La Brea, paleontologists have found fossils of many young bison. They can tell the age of the bison by the number of teeth, baby and permanent, in the jaw and by the amount of wear shown by the teeth. Young bison from the asphalt deposits are either two to four months old, fourteen to sixteen months old, or twenty-six to thirty months old. Each group is thus twelve months (one year) apart. No bison have yet been recovered that are of intermediate ages, five to thirteen months old or seventeen to twenty-five months old.
These clusters of ages indicate the bison were present at Rancho La Brea onIy during a few months of the year. If the calves of extinct bison were born at the same time of year as modern bison calves, then the extinct bison were present at Rancho La Brea every year during late spring.
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