The steppe bison may have been the most common animal found on the ice-age steppe of Pleistocene Alaska. The common ancestor to the steppe bison and to the modern day plains bison entered Alaska from Asia, via the Bering Land Bridge around 300,000 years ago. It – the common ancestor – became so successful that eventually it out-competed and displaced two ancient species of musk oxen (Matheus, pp. 62). The steppe bison is not at all dissimilar to the modern bison that one would find today on the plains of North America.
Taxonomically, the two share the same genus name. The steppe bison (Bison priscus) and the plains bison (Bison bison) evolved from that shared common ancestor and diverged to become distinct species as the bison migrated to different parts of the North American and Asian continents (Guthrie, pp. 15). In turn, the two were ultimately forced to adapt to different environments. With this in mind then, one major difference in the adaptations of the two species has to do with foraging behavior.
The grasslands that bison feed on today are covered annually in vast tracks of grasses that sprout up for a very short time in the summer season. What results in turn, is that the modern-day bison have to adapt to forage in enormous seasonal herds as they scour the plains en masse every summer. They devour the grasses during the relatively short time that they sprout up (Matheus, pp. 59).
In contrast, the ice-age steppe’s vegetation grew in smaller more discreet patches. At the same time though, there was a greater variety of plants (at least this was the case in the ice-age steppe of Alaska). Ultimately then, this extended the grazing season so that at any given time throughout the year, there would likely be a relatively ample supply of a given plant(s) that was able to be foraged upon by the steppe bison (Matheus, pp. 59).
What this meant in the end was that the steppe bison adapted to a different feeding lifestyle based on their environment; the vegetation didn’t cover vast tracks of land, neither did the steppe bison. So, if one were on a safari of ice-age Alaska, chances are that he or she would witness small groups of steppe bison scattered more or less intermittently throughout the landscape feeding on patchy tundra plants or small clumps of grasses on a more or less year-round basis (Matheus, pp. 59).
In terms of physical characteristics of the steppe bison, fossil evidence has shown that the steppe bison’s general posture and the size and shape of its neck, hump, and legs, are all different as compared to the bison that roam the North American plains today. In addition, the horns of the steppe bison were nearly twice as large as those belonging to the plains bison.
According to paleontologists, this unique posture, size, and shape lends credence to the theory that the steppe bison were not long-range migrators; supporting the mentioned feeding ecology of the steppe bison. In addition, fossil evidence seems to also indicate that the steppe bison stuck to hillsides rather than the plains and valley bottoms where one would normally find modern day plains bison today (Matheus, pp. 59).
Of the fossil evidence of ice age steppe bison that has been discovered in recent years, the most famous find was in the form of a steppe bison mummy who went by the name of Blue Babe. Over eons of time in silt sediments that were rich in iron but poor in phosphates, the organic remains of the mummy (which is rich in phosphates but poor in iron) became oxidized. What resulted was the remarkably blue, metallic sheen that came about upon mummy’s hide; hence the name Blue Babe (Guthrie, pp. 8).
Blue Babe was unearthed at a mine outside of Fairbanks in 1979 (Guthrie, pp. 7). Dale Guthrie of the University of Alaska excavated Blue Babe and performed the necropsy of the specimen. Based on Blue Babe’s position in the layered silt and nearby peat deposits, it was found that Blue Babe was more than 36,000 years old (Guthrie, pp. 7).
There were several clues in this archaeological detective story that led Guthrie to surmise what exactly happened to Blue Babe and what his story was. Because the mummy was fairly intact, Guthrie was able to detect the presence of horns and male genitalia; ultimately revealing then that Blue Babe was a bull. His age was estimated via horn annual sequences. These are constrictions made when the bison’s horns stop growing each winter (Guthrie, pp. 9); not unlike how one can determine a tree’s age be analyzing the rings around the cross section of its trunk.
It was also obvious that the carcass had been scavenged upon prior to its being buried by silt deposits. Vertebrae were missing and skin was torn and many muscle masses were absent while those tissues that did remain were remarkably preserved (Guthrie, pp. 9).
The story of the discovery of Blue Babe has proven to be a very significant development in the current knowledge that we have when it comes to ice-age steppe bison. For example, Blue Babe is more than just an example of finding skeletal remains of a steppe bison – skeletal remains are fairly abundant in fact. It’s so much more. A steppe bison mummy like Blue Babe can serve as a vehicle through which we can analyze many of the facets of steppe bison life that we otherwise wouldn’t have been able to do discover.
Guthrie explains that “we know from fossil remains that bison evolved very rapidly, undergoing remarkable changes in a fairly short time, rather like people. In fact, finding Blue Babe was comparable to finding a frozen Neanderthal, flesh and all (Guthrie, pp. 9).”
From the soft tissues that are present, we can determine much more about the ice age steppe bison. “Bone structure, tooth wear, even plant fragments contained in tiny pockets in the teeth can be analyzed; gut contents and other parts of the carcass (Guthrie, pp. 9)” can reveal many other things including social ecology, what it ate, and even how it interacted with other animals on the ice age steppe. It is clear that Blue Babe and a few other ice age mummies that have been found as of yet, are very likely only the beginning in the hunt for knowledge about ice age wildlife.
-Information found within this piece was accrued from research from the following publications:
Guthrie, Mary Lee. Blue Babe The Story of a Steppe Bison Mummy From Ice Age Alaska, Fairbanks:White Mammoth, 1988
Matheus, Paul E. “Pleistocene Mammals.” Alaska Geographic. 1994: 21.
