Some groups of mammals have relatively conservative coloration and body form, for example field mice (Microtus). A frozen Pleistocene-aged Microtus miurus carcass has been found near Fairbanks; the little mummy simply looks like a gray mouse. Because the appearance of Microtus has changed so little over time, mummies of this genus are unlikely to yield many surprises. Bison, however, are quite different. The two living species, Bison bonasus or wisent (fig. 4.1) in Eurasia and Bison bison (fig. 4.2) in North America, differ from each other in general body form and color. Additionally, Pleistocene steppe bison (Bison priscus) drawn on European cave walls (fig. 4.3) and portrayed in mobilary art are unlike either extant bison species. I use the term species advisedly, as late Pleistocene and living bison seem to form a single species complex.
Studies of fossil bones had already told us much about steppe bison before Blue Babe was found. By reconstructing skeletal shape, we could see that bison in Beringia were different from living bison (Guthrie 1980). Beringian bison were a little larger overall than extant bison (Skinner and Kaisen 1947), with disproportionately larger horns. But these subtle skeletal differences may be a poor clue to external appearances. For example, living bison species show much more variation in their coat patterns and hair color than in their skeletons. Within a related group, such as a genus, skeletons are comparatively similar. A bison mummy with hair provides much more information about overall appearance than one can ever get from a skeleton alone.
Fig. 4.1. Wisent or European bison (Bison bonasus). This species is found in Poland and the Soviet Union.
Fig. 4.2. American bison (Bison bison). This species is quite variable. The individual pictured here is a typical plains bison (Bison bison bison) with large hair bonnet and pantaloons.
Fig. 4.3. Late Pleistocene steppe bison (Bison priscus). Many bison portrayed in Paleolithic art are exquisitely rendered. From this artwork we get a good idea of the appearance of the steppe bison. This picture is from Santimamine in Spain.
Woolly Bison, Woolly Mammoths, Woolly Rhinos, and Unwoolly People
We characterize the northern, Pleistocene rhino and mammoth as “woolly” because their nearest analogue, living in more temperate regions have short hair. If bison were extinct and all we had for comparison were extant forms like cattle and Asian and African buffalo, we certainly would be talking about woolly bison too. Bison are part of modern natural history, so the adjective woolly is unnecessary, but they are one of the Pleistocene woollies. If the bison and musk-ox had become extinct 11,000 years ago, along with the mammoth and northern rhino, the title of this book would have been different and I would have been writing about a mummy of the extinct woolly bison.
In fact, northern horses were also woollies. Some horses portrayed in Paleolithic art have long “beards,” thick belly hair, and “feathered feet,” woolier than domestic horses raised at northern latitudes. Likewise, lions would have been very thickly coated, as are other felines adapted to northern climates. That northern subgroup could legitimately be referred to as Pleistocene woolly lions.
This train of thought about the woolly bison and its compatriots on the Mammoth Steppe is not all facetious. Pleistocene northern large mammals were adapted to extraordinarily low temperatures: wind chill factors must have regularly brought effective winter temperatures down to −60° F and lower. The animals’ tails and ears were short and well furred. Mammoths, rhinos, and horses had long hair even on their lower limbs.
The balance of the amount of energy taken in over the amount lost is central to the equation of whether a northern animal lives or dies each winter. Energy input can be reduced if the animal is more capable of conserving energy. Pelage is not simply a coat needed to keep warm. Heat is produced as a by-product of body metabolism, and in the case of a large herbivore, heat is a product of food composting by microorganisms. Most food we consume goes into maintaining our body temperature rather than meeting other basic requirements. Reducing heat loss, for a northern-adapted animal, directly affects use of fat reserves. Effective pelage can extend a little further the meager calories in winter food, which invariably are below maintenance. Woolliness can mean the difference between life and death.
The woolly pelt and runty tails and ears of these Pleistocene creatures are a signpost to us as we try to imagine what kind of ecological limit could have prevailed for about 20,000 years prior to the Holocene and probably why unwoolly humans did not inhabit Alaska until the “warmer” time during the end of the last glacial, as discussed in chapter 10. But pelage does more than retain warmth. It is an amalgam of a variety of functions that include the trappings of stature and social position.
Hair Length
When Walter Roman first discovered Blue Babe, only the posterior portion of the carcass was showing. Hair was not attached to the exposed skin, but tufts of black hair were found in the surrounding silt. By contrast, when the bison’s anterior end was excavated, we found the hair had slipped but was still held in place by frozen muck on the head and in patches over the forequarters and forelegs. I had often wondered how Pleistocene steppe bison must have looked, so finding hair preserved with the frozen carcass was really exciting for me; we carefully sampled and mapped this hair before the carcass was moved. Concurring with Geist (1971b), I had often observed (Guthrie 1980) that hair patterns of European Pleistocene bison (as portrayed on cave walls) were unlike either species of living bison.
Living bison from different geographic areas exhibit considerable differences in hair patterns. For example, “wood buffalo” (an unfortunate name because it suggests deep woodlands instead of the parkland clearings characteristic of their Canadian habitats), B. bison athabascae, have a high hump, small hair bonnet, and almost no chaps on the forelegs (Geist and Karsten 1977). Bison from the Caucasus, B. bonasus caucasicus, were different from Polish and Russian subspecies (Flerov 1977). Since Beringian bison occurred across such a vast area during the Pleistocene, it is likely they had geographic variations in hair color and pattern comparable to those of extant bison. Thus we could expect that Alaskan Blue Babe would resemble bison portrayed thousands of miles away by French and Spanish Paleolithic artists, but differ in certain details. Today ungulates occupying that geographic span exhibit subtle differences east and west. For example red deer, Cervus elaphus, moose, Alces alces, and caribou, Rangifer tarandus, vary between western Europe and eastern Asia, but are still justifiably considered members of their respective species.
Hair pattern among the three bison species B. bonasus, B. bison, and B. priscus differs most on certain parts of the body: the head, beard or ventral manes, foreleg pantaloons or chaps, and the hump. Fortunately these are located on the anterior part of the body—the very portion preserved on Blue Babe. But since our bison carcass was eaten from the dorsal side, skin and hair on the hump region were torn away. Likewise, thoracic vertebrae and their long neural arches were removed from the carcass and were not preserved. These parts would have told us about the hump. Eurasian B. bonasus, B. priscus, and North American B. bison all differ in neural arch contours and in hump hair patterns (Poplin 1984). We can use other steppe bison fossils to reconstruct the underlying bony part of the hump, and indeed this is the subject of chapter 5, but for now I confine my interest to hair and compare the hair contours of Blue Babe’s forelegs, head, beard, and tail with that of other bison.
Blue Babe retained sufficient hair to show that he lacked well-developed chaps or leggings. In this regard he is similar to the wood bison, B. bison athabascae, and the Eurasian B. priscus (fig. 4.4). Geist (1971b) pointed out that bison in cave paintings do not have long hair on the forelegs. The living European bison, B. bonasus, does not have pendulous leggings but does have long hair on the forelegs, which exaggerates the apparent thickness of the upper leg (fig. 4.5). Hair on the posterior side of the leg down from the olecronon process is 30 mm on the Alaskan mummy, compared to the much longer hair (up to 300 mm) of mature plains bison bulls.
Fig. 4.4. Variations of “legging
s” or “pantaloons” among bull bison. A comparison of pantaloon development shows Blue Babe is closest to the European Pleistocene steppe bison (B. priscus), which had negligible pantaloons. American plains bison (B. bison bison) has the largest. Both the European bison (B. bonasus) and the wood bison (B. bison athabascae) have traces of pantaloons.
The length of Blue Babe’s bonnet and forelock, hair over the frontal and parietal bones, is comparatively short for bison (fig. 4.6). It is about the same length as hair found on B. bonasus and, judging from cave paintings (fig. 4.7), must have been similar to the Eurasian B. priscus. North American bison have long hair above the eyes, producing a large bonnet. However, as first pointed out by Geist and Karsten (1977), B. bison athabascae has a smaller bonnet than plains bison, B. bison bison, and it is a rather different shape. The Alaskan bison mummy is quite unlike either extant American subspecies in this regard.
Only two parts of Blue Babe’s beard were preserved—just behind the lower lip and, farther posterior, just forward of the jaw angle. Both are short in comparison to B. bison bison and resemble other bison with short beards, especially B. priscus in cave art (fig. 4.7). There was simply not enough hair on Blue Babe to determine the overall shape of the ventral mane.
Blue Babe emerged without a tail. His tail (bones and skin) was later found attached to a patch of rump skin. Tail hair also differs among living bison (fig. 4.8), but unfortunately Blue Babe’s tail was hairless, so no comparisons of hair length are possible. We can evaluate color, however, because the broken bases of coarse black hairs can be seen embedded in the skin.
Fig. 4.5. Foreleg hair patterns of steppe bison from Paleolithic art. All living bison have some degree of hairy pantaloons on the foreleg, especially on the posterior part of the radius-ulna region (below the elbow). Pictures of steppe bison painted by Paleolithic artists show no indications of foreleg pantaloons. These examples of Paleolithic art are from (a and b) Niaux, (c) Candamo, (d) Le Portel, (e) Les Trois Frères, (f) Font-de-Gaume, and (g) Altamira. The hair on Blue Babe’s forelegs was similar to the pattern shown in these Paleolithic pictures of steppe bison.
Fig. 4.6. Head and facial hair. The hair removed from Blue Babe’s face and head was mapped and measured. The hair had “slipped” its attachment from the underlying skin but was still held in place by the surrounding wet silt. Hair length is shown in centimeters.
Fig. 4.7. Reconstructed face of steppe bison from Paleolithic art. Unlike American plains bison, steppe bison in Paleolithic art are pictured with short facial hair, an S-shaped profile, and a shorter beard. These Paleolithic bison portraits are from (a) Angles-sur-l’Anglin, (b) Le Puy de Lacan, (c) Isturitz, and (d) Les Trois Frères. Remnants of facial hair on Blue Babe (e) show a similar pattern.
Blue Babe’s tail without hair is around 20 cm long, much smaller than B. bison’s tail. Van Zyll de Jong (1986) shows that the mean length of tail, without tassel, for B. bison bison was 42 cm and that that of B. bison athabascae was 50 cm (both male samples). Tails of living European bison are much longer (Flerov 1979 illustrates the bison from the Caucasus as having a small tail). Flerov (1977) estimates the tail of a female Siberian bison mummy at 30 cm, longer than Blue Babe’s but shorter than living European bison.
Geist (1971a) has shown that tail length is important socially and seems negatively correlated with the degree of cephalization of social display paraphernalia. But tail length is also related to severity of winter. Ungulates living in the far north generally have shorter tails than their warmer climate counterparts. Long tails (speaking of the structural bone-blood-skin part of the tail and not hair) are a source of heat loss. Additionally the insect season in the far north is so short that the advantage of a fly switch for hind quarters is small. Northern ungulates all have short tails—just enough to cover the ano-vulvar area as an insect-proof seal and an insulating cap. Consistent with this, the woolly mammoth and woolly rhino pictured in Paleolithic art have smaller tails than their living analogues in more southern latitudes.
Fig. 4.8. Bison tail lengths. Tail length varies among bison groups. European B. bonasus have the largest tails and plains bison (B. bison bison) have the shortest of living bison. However, Blue Babe’s tail was even shorter. No full-length hairs remained on the tail, so the tail pictured here is a tentative reconstruction based on bone and skin remains. The steppe bison in cave art have long, well-furred tails like European bison. Presumably tail length varied from west to east across the Mammoth Steppe because the continental climatic effects in the east produced (and still produce) colder winters.
Although Blue Babe was a steppe bison (B. priscus), his tail was shorter than tails of European steppe bison (B. priscus) shown in Paleolithic art (fig. 4.8), probably due to the milder winters European steppe bison experienced, especially during the warm and wet Pleistocene interstadials. Winters were never warm for Alaskan and Siberian bison, even during the interstadials, so those bison have short tails. American bison, B. bison, which are derived from native Beringian bison, seem to have retained short tails as they moved south. Winters on the High Plains are not as severe as those in Alaska, but they are not mild.
In addition to these hair patterns, other areas on the bison mummy were not preserved. For example, lack of hair on the shoulders did not allow us to assess whether a shoulder mantle was present, as in B. bison bison, or almost absent, as in B. bonasus, B. bison athabascae, or Eurasian B. priscus (in Paleolithic art). Also missing from the specimen was the penile tuft, which is most developed in the plains bison, B. bison bison, and least developed in the European bison, B. bonasus.
Fig. 4.9. Bison color patterns. A bull typical of each “species” is shown here along with a reconstruction of steppe bison from Paleolithic art.
Blue Babe and Bison of Other Colors
The color patterns of Blue Babe and subspecific variants of living bison species are compared in figure 4.9. There is some variability in pelage within bison populations as well as some geographic variability so these comparisons are of the more typical forms. Coat color is a fairly labile character among mammals, unlike teeth or feet. The evolution of teeth and feet are tied to conservative and exacting environmental constraints, but external appearance is linked more closely with less conservative traits such as social behavior; as a consequence, external appearance is one of the more variable characters between groups. Just as external appearance is the character that differs most among living bison, so it would be expected to differ on an evolutionary gradient. Because the mummy is an adult bull, I compare him only with adult bulls from other bison species.
European bison, B. bonasus, are the most homogenously colored bison. Their coat is a uniformly dark rusty brown. The hump area is subtly lighter and the face forward of the ear a darker brown. Among bison I observed in the Prioksko-Terransny Reserve on the Oka River, USSR, there were some bulls with black faces. Skins I have seen from Caucasian subspecies had a similar homogenous color, but were darker than Russian and Polish bison. Flerov (1977) also pictures Caucasian B. bonasus as uniformly dark.
American plains bison are more dramatically colored; they are, overall, a deep rust brown. Most bulls have jet black hair on the head, neck, and foreleg (a few individuals are more “cow” colored, with a very dark brownish tone in these parts). A stripe of dark hair runs down the central part of the hump, in contrast with the light sand of the hump itself. This sandy hair extends ventrally to the elbow, or olecranon process, as part of a thick mantle of hair covering the shoulders. Although European bison bulls have a shoulder mantle, it is not exaggerated, nor does it have a discreet posterior border as in American bison. Posterior to this shoulder mantle, hair on American bison bulls is much shorter and quite dark, ranging from black to dark brown. These contrasting tones produce a striking late-autumn appearance before the pelage is bleached by sun and weather. Geist and Karsten (1977) have shown that the wood bison subspecies (B. b. athabascae) is not so dramatically colored as the plains subspecies: wood bison have a darker,
more reddish hump that is less dramatically colored than that of the plains bison.
In contrast to these variants of living bison, Blue Babe looked like a dark bay horse; he was mainly a rich dark brown with black “points” on his face, legs, and tail. His forelegs were dark brown, but hair on the lower leg, from metacarpals to the hoof, was so dark it was almost black. The face, or anterior part of the head, was black, reaching posterior only to the eyes and dorsally toward the frontals on a line between the anterior edges of the horn bases (fig. 4.10). The rest of the head, bonnet, cheeks, and ears was a rusty brown. The beard or ventral mane was black, at least on its anterior parts (where hair remained on the mummy). Only a few hairs remained on the shoulders. These were a light reddish brown. No light sandy-colored hair, characteristic of living American plains bison, was found with Blue Babe. The hair that came out of wet-screened silt from the site was either very black or reddish brown.
Geist and Karsten (1977) showed that the ventral name of B. b. athabascae was poorly developed, while that of the plains subspecies, B. b. bison, and the European wisent, B. bonasus, was quite long in both males and females. Unfortunately Blue Babe’s ventral mane posterior to the beard was not preserved. As already noted, the mummy’s tail hairs were not preserved, but broken bases of hair still in the tail skin were very black. This tail hair resembles that of American bison tails (which ranges from black to very dark brown) and is quite different from the long reddish brown tail hair of European bison.
Fig. 4.10. Blue Babes’s head color. Hair samples were collected as the bison emerged and during necropsy. Most of the hair had already slipped, but some facial hair was in place. On the front of the face the hair was almost jet black. On the sides of the head it was dark brown, and one sample from the shoulder was a reddish brown.
Frozen Fauna of the Mammoth Steppe: The Story of Blue Babe Page 12