As you progress through the bison exhibit, you will follow the bison linage back in time. To fully appreciate the size change associated with bison evolution, keep in mind that all of the bison skulls are displayed on identical-sized backboards.
Bison vs. Buffalo
The North American Plains Bison (Bison bison bison) is commonly called a buffalo. However, "buffalo" refers to the African cape buffalo (Synceras caffer) and the Asian water buffalo (Bubalus bubalis), which are only very distantly related to the local bison. When European settlers first arrived in North America, they thought the bison here resembled the buffalo that they had seen in Asia and Africa. The French called the plains bison "la boeuf," meaning "ox" or "beef," because it looked like the buffalo and cattle they knew. The term "bison" is actually Greek for "ox-like" and refers to the North American plains bison and the Canadian woods bison (Bison bison athabascae). The Canadian woods bison is taller and less stocky than the American plains bison.
Bison bison bison
This specimen came to our museum from the 777 Ranch. It was approximately 8.5 years old and is of average size. The horn span, which is measured from tip to tip of the horn cores, is 24.0 inches (610 mm). The horn cores extend approximately 75% into the horn sheaths covering the horns. Most Bison bison bison have a horn span between 23.0 inches (585 mm) and 29.0 inches (735 mm). The largest bison grow to be 6'6" at their tallest point and can weigh up to 2,200 pounds. Females can grow up to 5'9" and can weigh 1,800 pounds. These animals can run up to 40 miles per hour. Today, Bison bison bison inhabits most of the lower 48 United States and even northern Mexico (see map-brown).
Throughout the history of Paleo-Indians and Native Americans, Bison bison bison has played an essential role. Before the mid-1800s, every part of bison was utilized by humans-the meat was used for food, the bladders were used for water bags, the bones were used for tools, and the hides were used to make clothes and shelters. It is estimated that 10 million bison may have once roamed the North American plains. In 1804, Lewis and Clark described these animals, which were unknown to the Eastern United States, as "...immence herds of Buffaloe... I do not think I exagerate when I estimate the number of Buffaloe which could be comprehended at one view to amount to 3000... - Meriwether Lewis, Sept. 17, 1804"
By 1884, humans had hunted bison to the brink of extinction and the bison population was estimated to be only 2,500. In 1884, the U.S. government passed a law outlawing the hunting of bison. Today, it is estimated that there are between 500,000 and 750,000 Bison bison bison living on private ranches and protected lands.
This ancient bison from Bennett County, SD, was donated to our museum by the South Dakota Geological Survey in 1968. The horn span is 34.1 inches (865 mm), average for this species. The horn span in Bison antiquus can be 31.0 inches (780 mm) to 39.0 inches (980 mm). The downward curvature of the horns at the base is a defining characteristic of Bison antiquus. These bison lived in the late Pleistocene and early Holocene (recent time) epochs, approximately 80,000 to 8,000 years ago. Bison antiquus inhabited almost all of North America, from Alaska to northern Mexico and west of the Mississippi River (see map-green).
Like Bison bison bison, Bison antiquus was also hunted by Paleo-Indians at sites such as the Alberta Culture's Hudson-Meng Bison Kill Site near Crawford, NE, which is about 10,000 years old. At the Vore Buffalo Jump Site, Native Americans used sinkholes to trap and kill Bison bison bison. At both of these sites, most of the bones were left behind, indicating that not all parts of the bison were used.
This specimen was found in Fairbanks, Alaska on April 17, 1951 and came to our museum from the Frick Lab at the American Museum of Natural History in New York City. The average Bison crassicornis had a horn span between 30.1 inches (765 mm) and 52.0 inches (1322 mm). The horn span measures an approximately average width of 43.3 inches (1100 mm). Like Bison bison bison, this specimen still has horn sheaths covering the horn cores. If you look closely at the upper jaw on the right side, you will notice some abnormal bone growth that occurred during this animal's life. This pathology (a deviation from a healthy condition) is at a muscle attachment site and may have been caused by an abscess. Bison crassicornis lived approximately 600,000 to 30,000 years ago, during the medial to late Pleistocene epoch.
This bison skull was found in Midland, SD, in 1958 and was donated to our museum by Lester Nilson. The skull had to be reconstructed from many pieces. In 1960, Morton Green and Harold Martin researched this specimen and published "Bison latifrons in South Dakota" in the Journal of Paleontology. This was the first Bison latifrons found in South Dakota and, at the time, was the northern-most occurrence. Compared to other bison, this specimen is truly a giant. Although the horn span is an impressive 68.0 inches (1726 mm), this is average for this species with a range of 56.0 inches (1422 mm) to 83.8 inches (2129 mm). The largest Bison latifrons ever found had a horn span of 114 inches (2895.6 mm), or 9.5 feet. Bison latifrons originated approximately 800,000 years ago in the early Pleistocene epoch and lived until about 75,000 years ago (beginning of the late Pleistocene).
According to current research, Bison latifrons is not a direct ancestor of the Bison bison bison. Bison latifrons did share a common ancestor with Bison crassicornis, who produced the Bison bison bison lineage. Bison latifrons produced a now extinct lineage. Even though the Bison latifrons and the Bison bison bison are not directly related, they do share very similar dentition (teeth), which is very important to consider in paleontology. In fact, all of the bison in this display have very similar dentition. Even though the skulls are quite different in size, all of these bison had nearly identically sized teeth.
This 'steppe bison' came to our museum from Livingood, Alaska, in a 1951 exchange. Most Bison priscus had a horn span between 31.5 inches (800 mm) and 47.2 inches (1200 mm), making this specimen's span of 40 inches (1015 mm) about average. These bison originated 5.0 million years ago, during the early Pliocene epoch, in the tropics of southern Europe.
The most famous Bison priscus ever found is known as "Blue Babe". It was found in the permafrost near Fairbanks, Alaska in 1979. Because this specimen was completely frozen, the soft tissues were preserved in addition to the bones. This allows us to visualize what Bison priscus looked like and what the environment was like at the time.
Migration and Evolution (Phase 1)
Bison priscus (maroon) migrated across the Beringian Land Bridge between present-day Siberia and Alaska at approximately 3 miles per year. These bison migrated in three waves-the first group evolved into Bison latifrons, the second evolved into Bison crassicornis, and third evolved into Bison antiquus, the direct ancestor of our modern species.
Migration and Evolution (Phase 2)
Bison crassicornis (black) migrated from Siberia to Alaska during the second wave of bison migration across the Beringian Land Bridge. They remained in what is now Alaska and northern Canada for their entire existence. At this time, the land covered in ice and experiencing a continuous cycle of glacial advancement and retreat. Bison latifrons (blue) migrated to Alaska from Siberia in the first wave of bison migration across the Beringian Land Bridge. When the ice retreated, it opened a path southward. Bison latifrons migrated further south and it seems they preferred the warmer environment in what is now the southern United States. As Bison latifrons settled into the southern U.S., they became smaller over time as they adjusted to the presence of more grasses and fewer sedges.
Migration and Evolution (Phase 3)
North American Bison bison bison (brown) inhabit most of the lower 48 United States and even northern Mexico. These bison evolved from Bison antiquus (green) about 12,000 years ago in the late Pleistocene epoch. Bison antiquus are descended from the third wave of bison migrations from Siberia to North America via the Beringian Land Bridge.
Time Span vs. Horn Span
This graph shows the size of the horn span compared to where the species appear in the geologic time scale.