ABSTRACT:
Sasquatch footprint casts from Elk Wallow (Walla Walla), previously
examined in detail by Krantz (1983), are discussed with respect to the
presence of a large sole pad. A sole pad is an important component in
locomotion, and reconstructions of anatomy and gait must take it into
account. Because large animals compensate for heavy weight principally
through locomotor pattern, a large, unknown biped need not have enormous
stresses acting on the moving lower limbs, but would have a gait different
from living bipedal hominids. Anatomical reconstructions must also take
this into account. Dermatoglyphic evidence, if abundant, can be used
to reconstruct behavior. Hence, it is possible that future research
utilizing prints and track ways of these large, unknown animals in the
Pacific Northwest may yield more information about locomotion and behavior
than is presently the case, if investigators are willing to entertain
the possibility that the animals responsible for the prints may be unlike
any known mammal in anatomy and locomotion. Krantz's (1983) identification
of the prints as hominid, by virtue of an adducted hallux, is questioned.
INTRODUCTION
In his recent
paper on the Elk Wallow (Walla Walla) Sasquatch footprints, Krantz (1983)
presents a detailed summary of the configurations of three footprint casts,
paying particularly close attention to dermatoglyphic data. Skepticism
as to whether dermatoglyphic patterns can be preserved on plaster casts
is answered by Krantz's experimental proof that a human thumbprint can
be transferred from skin to soil to plaster, and by the fact that criminal
identification by dermatoglyphics from footprints imprinted in soil is
acceptable procedure by police departments in two countries. Krantz then
investigates the dermatoglyphic patterns of the casts, and concludes from
this evidence that the makers of the prints were primates. Krantz further
identifies the Elk Wallow prints as made by a specific category of primates,
hominids (Krantz 1983: 53)--that is, members of the zoological family
to which living humans and their extinct relatives belong.
In this paper, I shall examine the sole pad, a feature of the Elk Wallow
prints, which Krantz does not discuss in as much detail as the dermatoglyphic
evidence. This feature is, however, important for reconstructing anatomy
and locomotion. I shall also examine the influence of body size on locomotion,
and indicate some ways in which dermatoglyphic evidence, if more abundant,
may be used to reconstruct elements of behavior. I conclude by stressing
the probability that the makers of the Elk Wallow prints are unique among
mammals in terms of anatomy and locomotion, and that identification of
the prints as hominid in origin, on the basis of a single trait (an adducted
hallux), is incorrect.
THE SOLE PAD
One of the striking morphological features documented by the casts is
the apparent presence of an extremely thick, flexible pad on the sole
of the Elk Wallow feet. Given the impression of a stone in the middle
of the "full right" cast, and a photograph of the actual print
with stone in place, Krantz (1983: 64) estimates the minimal thickness
of this pad as slightly greater than 2 cm in the middle of the sole. Anatomical
evidence from the gorilla, largest of the living primates, indicates that
a sole pad can exist with dermatoglyphic patterns intact on the plantar
surface. It is therefore possible for a very large mammal to possess a
thick, flexible sole pad with dermatoglyphics, and not merely ridged skin.
One might assume, by analogy with living mammals possessing such pads
(Morton 1935), that the sole pad of an unknown mammal would be composed
of fat and tough, fibrous connective tissue. The thick, fibrous strands
would bind the skin to the deep fascia (plantar aponeurosis), and would
form small compartments of firm and resilient fat. The depth of the pad
might vary along the foot according to weight-bearing considerations.
A sole pad is therefore a biologically normal structure, and one can use
evidence from living mammals to infer its general composition in a form
whose anatomy is unknown. Is it possible to estimate the depth of the
sole pad in the Elk Wallow creatures using available information on sole
pad thickness in living mammals? Such information exists for two primate
species, gorillas and hominids.
Fat and connective tissue comprise the sole pad in the gorilla. Thick
skin covers the sole of the foot, and is underlain by fat and fibrous
tissue at the lateral border of the foot. The depth of this pad increases
posteriorly, and reaches a maximum depth of 2.5 cm under the heel (Raven
1950: 71). In modern, bipedal humans, the sole pad is an important weight-beating
structure which is so compressible and shock-absorbing that a fall directly
on the heel which shatters the calcaneus may leave no mark on the sole
pad (Klenerman et al. 1976). The skin on the sole is thickened, especially
at the heel, even in human fetuses, but the skin and the underlying pad
of lobulated fat and collagen fibers is also subject to some variation
in depth. Certain congenital diseases, accidents which result in the foot
being placed in a cast, or prolonged bed rest may cause such thinning
of the sole pad that walking is almost impossible. In acromegaly, this
sole pad becomes very much thicker than normal, sometimes achieving a
state "like a built-in layer of crepe rubber" (Klenerman et
al. 1976: 137). Data on the average thickness of the human sole pad at
the heel region do not seem to be readily available. In dissections of
cadavers, the skin of the sole is so thick and firmly bound to the underlying
lobulated fat that it is difficult to disclose the plantar aponeurosis;
I would estimate a thickness of about 2 cm in the human cadaver. Histological
study of the subcutaneous tissue of the gorilla foot seems to indicate
a composition and thickness similar to that of man (Straus 1950: 217).
An average greatest sole pad thickness of 2.5 cm may therefore be nearer
the modem human norm.
Note that the sole pad is about the same thickness in hominids and gorillas,
although gorilla weight is approximately three times that of hominids.
I now make two assumptions. First, I assume that bipedal locomotion, in
which all of the body weight is supported by the hind limbs, experiences
more selection pressure for cushioning of the foot than is the case in
quadrupedal locomotion. The thickness of the sole pad in the quadrupedal,
knuckle-walking gorilla would therefore be increased in a biped of gorilla
size. Professional human runners, who experience impact forces at heel
strike of three to five times that experienced during walking (Roy and
Irvin 1983: 422), are forced to control foot movement and absorb shock
with specially constructed shoes and orthotic devices. In effect, they
must create artificial sole pads in addition to the natural cushioning
of the sole, and even then cushioning is not always adequate to prevent
injury in running athletes. This is especially the case in marathon running,
where impact forces acting over a distance often cause overuse injuries.
Running bipedal hominids thus experience foot impact forces several times
that experienced during walking, and often suffer as a result of inadequate
natural sole pads, which have been evolved to withstand walking impact.
I believe that this demonstrates that, if bipedal hominid body weight
were multiplied several times--the equivalent of the increase in impact
force experienced during running--the thickness of the sole pad would
be correspondingly increased to ensure efficient bipedal walking. In short,
if gorillas were bipeds instead of quadrupeds, their average greatest
sole pad thickness would perhaps be about 6-7.5 cm. I also assume that
the cushioning efficiency of the sole pad in walking modem hominids is
at or near the biomechanical optimum for a bipedal mammal.
If the ankle of the Elk Wallow creatures were set farther forward on the
foot than is the case in modem hominids (Krantz 1983: 60), the greatest
thickness of the sole pad might occur closer to the front of the foot,
and not at the heel, as is the case in gorillas and hominids. The exact
position of this maximum thickness would depend on the manner in which
the foot contacts the substrate--that is, whether the heel or the forward
part of the foot contacts the ground first (or perhaps the entire sole
contacts the ground at once). It is possible therefore, that Krantz has
greatly underestimated the thickness of the pad at the middle of the sole,
perhaps close to where its greatest thickness would occur. If the average
thickness of the sole pad is about 2-2.5 cm in the heel region of modern
bipedal hominids with a mean weight of 60 kg (Eisenberg 1981), then it
is not unreasonable to reconstruct the pad on the sole of the Elk Wallow
creatures as being between 10-15 cm at its greatest thickness, if these
creatures are bipedal and have a weight of 400 kg, as Krantz estimates.
I am simply multiplying the thickness of the hominid sole pad by six to
achieve a similar kind of cushioning efficiency in an unknown bipedal
mammal whose body weight may be six times greater than that of hominids.
Again, this reconstruction assumes that the cushioning efficiency of the
sole pad in modern hominids is at or near the biomechanical optimum for
bipedal mammals. Details imprinted on the side of the Elk Wallow prints
and the edges of the footprint indentations themselves indicate that an
extremely flexible sole pad is present (Krantz 1983: 64-65).
A question now presents itself. If the Elk Wallow sole pad should have
a thickness of 1 0-15 cm at its greatest depth, and should be extremely
flexible, then what is the likelihood of the prints themselves preserving
an extremely detailed record of anatomy and locomotion? Would not the
collapse of the sidewalls of the print impressions as the foot is withdrawn
obscure fine details? The print impressions would be wider at the bottom
than the top, and would be subject to such collapse. Some record of wider
span at the bottom seems to be preserved in the Elk Wallow prints. Slight
movements of the flexible tissue of the sole would tend to erase details,
even if collapse of soil at the edges of the prints did not occur. It
might be that, as body weight causes compression of the sole pad, the
foot would expand and extend laterally. Analysis of gait would be incomplete
or inaccurate if it did not allow for these lateral shifts, which would
significantly broaden the print. Very detailed analysis of locomotion
by examination of footprints to yield evidence of the sequence of weight
transfer (Napier 1973), and taxonomic assignation by fine examination
of dermatoglyphics might therefore be subject to a certain margin of error.
Only under exceptional conditions would the substrate be able to preserve
an accurate picture of the living foot. The fine-grained loess soil at
the Elk Wallow site may represent such conditions, but this is not the
case for most areas in which prints of creatures like those presumably
responsible for these prints have been collected and studied.
Another question concerns the depth of the prints themselves. If body
weight is supported by such a sole pad, the large surface area of the
sole would spread the weight over a relatively wide area, so that only
faint tracks would be left on hard ground. In the elephant, for example,
the cushioning sole pad is so thick that the foot has an externally plantigrade
appearance, although the foot skeleton is held in a semi-digitigrade position.
That is, the elephant's heel appears externally to be touching the ground,
but the animal is actually walking with the heel portion of its foot skeleton
raised. The large, thick ~ole pad allows the animal to traverse extremely
rough terrain and move silently, but the sole pad also spreads the great
body weight so efficiently that individual tracks, although they cover
a large area, are fainter than one might assume from the known body weight.
Sikes (1971: Plate 8) shows the prints of one African elephant in firm,
sandy soil. Although the print of one foot overlies the other print, pressing
the soil down twice, the impressions are rather shallow. If a large sole
pad spreads even massive body weight so efficiently, why do the Elk Wallow
prints appear so deep? It is unlikely that the body weight exceeds the
estimated 400 kg, and the sediment does not seem to have been very soft.
It is possible that the sole pad of the Elk Wallow creatures is not as
efficient as that of the elephant at distributing body weight over a large
surface, but some type of sole pad does seem to have been present, and
the estimate of its greatest depth is based on the weight inferred by
Krantz (1983).
I am reasonably certain that the Elk Wallow prints are authentic. However,
I do have reservations about the prints recording a precise and accurate
picture of details of weight transfer. While certain portions of the casts
show remarkably fine structures, Krantz (1983) is forced to select small
areas from the casts to discuss dermatoglyphic evidence. This would appear
to indicate that the flexible sole tissue is erasing detail. I am also
puzzled by the depth of the prints. Perhaps experimentation with an artificial
sole pad which could mimic the texture of the thick sole pad tissue in
such mammals as camelids and elephants might resolve how much known detail
can be reliably transferred from such a device onto loess soil, and thence
onto plaster, and whether the dynamics of locomotion can be inferred from
print and cast. The question of the depth of print impressions in relation
to body weight might also be examined, if the device were capable of dissipating
load like living tissue.
If the question of the depth of the impressions can be answered, the likelihood
that the Elk Wallow creatures possess a large sole pad could lead to new
insights into the anatomy and locomotion of such unknown animals. One
interesting possibility is that the Elk Wallow creatures, like elephants,
might have a semi-digitigrade foot skeleton, although the large cushioning
sole pad would give the external foot a plantigrade appearance. This might
account for the great amount of weight apparently carried on the forepart
of the foot. Rotational movement at the ankle joint would be lost, however,
so that envisioning an enlarged version of a hominid subtalar joint, for
example, would be incorrect. Although Krantz (1977) has argued that the
digits of the Sasquatch foot are short for biomechanical reasons, the
short visible part of the digits might be arrayed at the forward edge
of the sole pad, and their true length be obscured by the structure of
the pad. The hind limb anatomy and gait of the Elk Wallow creatures may
be unique among mammals, and not easily inferred from comparison with
living mammals of a single order, even if the dermatoglyphic evidence
points to the primates.
Finally, as Napier
(1973) has stressed, track ways of animals, and not single isolated prints,
are necessary for detailed analysis of gait. Future researchers should
be prepared to make casts of partial track ways--obviously not an easy
task.
BODY SIZE AND LOCOMOTION
Sasquatch
foot anatomy has been examined in detail by Krantz (1977), who argues
that, in comparison with living hominids, these creatures have a lengthened
heel and a shortened forefoot. This leads to a reconstruction in which
the ankle joint is set farther forward on the foot, a point which is also
made in Krantz (1983). The power arm of the foot is thereby lengthened
and the load arm is shortened. This reconstruction is derived from Krantz's
belief that changing the length of the lever arms in the foot is the simplest
evolutionary solution to the problem posed by large body size in bipeds.
Large body size creates a problem if body weight increases cubically,
while skeletal dimensions increase areally. Hence, Krantz proposes that
allometric or size-related considerations affect body design in bipeds,
which are significantly larger than modern hominids.
Recent research on the allometry of mammalian limb bones, however, demonstrates
that the lengths and diameters of limb bones in a series of species stretching
from shrew to elephant-size scale close to geometric similarity (Alexander
et al. 1979a). Obviously, there are tremendous differences in adult body
mass, but the linear dimensions of the limb bones in the series are geometrically
similar. For example, the elephant femur and humerus are not very much
wider relative to their length than in much smaller animals. This surprising
conclusion--which upsets statements on the allometric relationship between
limb bone dimensions and body weight going back to the time of Galileo--also
holds true within the primates, because six primate species (including
modern hominids) are included in the mammalian survey (Alexander et al.
1979a). This research implies that the limb bones of a biped much larger
than a modern hominid need not be strikingly different in form in order
to support a much greater body weight.
Stresses on limb bones of moving animals versus stationary animals have
also been examined (Alexander 1977, Alexander et al. 1979b). Because movement
causes several times more stress on the limb bones than does standing
still, the increase of limb bone diameter in step with length increase
becomes even more surprising. How do large animals exist in spite of what
appears to be a biomechanical paradox? The answer lies in gait differences.
Movement patterns of different sized mammals demonstrate that the large
mammals move in such a way that their limbs remain in contact with the
ground for a longer time, which decreases stress in the limb bones. The
reduction of relative stresses in these bones compensates for greater
body weight. The maximum stresses acting on the limbs of large animals
are comparable to those of smaller animals, so that the bones of the larger
species do not need to be much more robust (Alexander 1977, Alexander
et al. 1979b).
Two conclusions can be drawn from this research. The first is that unknown
bipedal animals much larger than modern hominids, but hominid-like in
position of the trunk and use of a striding gait in locomotion, are not
an a priori impossibility. The second conclusion is that, because large
animals compensate for heavy bodies mainly through gait pattern, differences
between large, unknown bipeds and hominids might lie in the amount and
length of time of foot contact with the ground, rather than in gross differences
in skeletal structure.
DERMATOGLYPHICS
AND THE RECONSTRUCTION OF BEHAVIOR
Dermatoglyphic evidence from the Elk Wallow prints is necessarily confined
at present to description and taxonomic assignation. Nevertheless, it
is possible that, if such evidence were to become more abundant in the
future, details of behavior might be reconstructed from dermatoglyphic
evidence. Primate species can be used to illustrate this contention.
There is a substantial body of data on the volar skin and dermatoglyphics
of primates. Cartmill (1974, 1979) demonstrated that volar skin was subject
to selection pressure involving allometry, with volar pad coalescence
occurring in larger primates as an adaptation to increase its frictional
characteristics. Biegert (1963) advocated the use of primate dermatoglyphics
and volar pad structure as taxonomic traits, and in the reconstruction
of phylogeny, but Meier (1980) reported evidence that dermatoglyphic pattern
intensity in non-human primates may be more related to function than it
is to taxonomy or phylogeny. The use of dermatoglyphics as indicators
of biological distance in humans has equivocal results, which do not necessarily
coincide with biochemical or anthropometrical variation (Meier 1980).
This may not be the case in non-human primate species.
Dermatoglyphics appear to be useful in identifying individual animals,
demonstrating group cohesiveness, and allowing analysis of introgressive
hybridization in an Ethiopian site with troops of both olive and hamadryas
baboons, and a troop of hybrids of these two species (Jolly and Peterson
1984). Analysis of dermatoglyphics in mantled howler monkeys on Barro
Colorado Island, Panama, allowed inferences to be made about the evolutionary
history of these monkeys on the island (Froehlich and Thorington 1982).
Inferences about the colonization of one of the peninsulas by two different
howler troops, and the differentiation of neighboring troops from a common
troop are based on dermatoglyphic analysis. Thus, dermatoglyphic evidence
can be used not simply for taxonomic or phylogenetic purposes, but for
social and historical reconstruction as well. If the Elk Wallow prints
and associated dermatoglyphics hold up under detailed scrutiny, and if
many additional prints with dermatoglyphics are found, the possibility
exists that the genetic relatedness of individuals can be assessed, along
with the possibility of differentiating variation at a group level, allowing
inferences about the existence of social groups, gene flow, and the process
of dispersal of groups or individuals within a given habitat unit.
CONCLUSION
There is
a reasonable probability that the Elk Wallow prints were made by an unknown
animal species. I have examined the presence of a large sole pad in some
detail, and have reconstructed a sole pad whose greatest depth would approximate
10-15 cm. Two problems still concern me: 1) the degree to which the prints
preserve undistorted information about dermatoglyphic pattern and locomotion,
and 2) the depth of the print impressions, in spite of the presence of
a sole pad which should efficiently distribute body weight.
I have also discussed the interaction of body weight and locomotion, and
have indicated that, because large animals compensate for great weight
mainly through gait pattern, gross differences in skeletal structure between
large unknown bipeds and modern hominids are not necessarily to be expected.
A larger biped would, however, need a greater length of time of foot contact
with the ground. Furthermore, unknown bipedal animals much larger than
modern hominids, but hominid-like in trunk position and use of a striding
gait, are not intrinsically impossible.
If dermatoglyphic evidence similar to that from the Elk Wallow prints
were to become more abundant, behavioral reconstruction could be attempted,
given the lines of behavioral research that have opened recently from
dermatoglyphic research in primates.
Finally, I question Krantz's identification of the Elk Wallow prints as "hominid," by virtue of the marked adduction of digit I (Krantz
1983: 53). Living primates show many variations in extremity structure.
For example, New World ateline and Old World colobine monkeys independently
reduced digit I in the hand, sometimes to a remarkable degree. This would
be an example of the parallel evolution of a trait in two different infraorders
of living primates. Conversely, it is also possible for members of a single
family to show remarkable divergence in extremity structure. Thus, the
African great apes develop knuckle-walking specializations of the hands
while the orang-utan does not, instead lengthening the entire hand and
digits II-V and reducing digit I. The foot of the orang-utan is similarly
lengthened, with concomitant elongation of digits II-V, and reduction
of digit I, sometimes to a vestigial state. Given the great evolutionary
potential for variation in extremity structure documented in living primates,
it may be problematic to identify the Elk Wallow creatures as hominids
by virtue of a markedly adducted hallux. In any case, Krantz also lists
a number of traits, which completely differentiate the Elk Wallow prints
from those of modern or extinct hominids, such as the anterior placement
of the ankle and extremely short digits. Although reported sightings of
these animals emphasize similarities to hominids, and dermatoglyphic evidence
points to the primate order, analysis of the prints demonstrates the existence
of foot structure and locomotion unlike anything known among mammals.
The prints are not simply enlarged and broadened versions of hominid prints.
Therefore, the makers of the prints do not have the anatomy, body proportions,
and locomotion of living hominids.
REFERENCES CITED
Alexander,
Robert McN.
1977 Allometry of the Limbs of Antelopes (Bovidae). Journal of Zoology,
London, Vol. 183: 125-46.
Alexander, Robert McN., A. S. Jayes, G. M. O. Maloiy, and E. M. Wathuta
1979a Allometry of the Limb Bones of Mammals from Shrews (Sorex) to Elephant
(Loxodonta). Journal of Zoology, London, Vol. 189: 305-14.
Alexander, Robert McN., G. M. O. Maloiy, B. Hunter, A. S. Jayes, and J.
Nturibi
1979b Mechanical Stresses in Fast Locomotion in Buffalo (Syncerus caffer)
and Elephant (Loxodonta africana). Journal of Zoology, London, Vol. 189:135-44.
Biegert, Josef
1963 The Evolution of Characteristics of the Skull, Hands, and Feet for
Primate Taxonomy. In Sherwood L. Washburn (ed.), Classification and Human
Evolution. Chicago: Aldine.
Cartmill, Matt
1974 Pads and Claws in Arboreal Locomotion. In Farish A. Jenkins (ed.),
Primate Locomotion. New York: Academic Press.
1979 The Volar Skin of Primates: Its Frictional Characteristics and their
Functional Significance. American Journal of Physical Anthropology, Vol.
50:497-510.
Eisenberg, John
1981 The Mammalian Radiations. Chicago: University of Chicago Press.
Froehlich, Jeffry W., and Richard W. Thorington
1982 The Genetic Structure and Socioecology of Howler Monkeys (Alouatta
palliata) on Barro Colorado Island. In Egbert G. Leigh, A. S. Rand, and
Donald M. Windsor (eds.), The Ecology ora Tropical Forest. Seasonal Rhythms
and Long-Term Changes. Washington, D.C.: Smithsonian Institution Press.
Jolly, Clifford J., and A. K. Peterson
1984 Variation in the Palmar Dermatoglyphics of Ethiopian Baboons. American
Journal of Physical Anthropology, Vol. 63:175-76 (abstract).
Klenerman, L., et al.
1976 Common Causes of Pain in the Region of the Foot. In L. Klenerman
(ed.), The Foot and Its Disorders. Oxford: Blackwell Scientific Publications.
Krantz, Grover S.
1977 Anatomy of the Sasquatch Foot. In Roderick Sprague and Grover S.
Krantz (eds.), The Scientist Looks at the Sasquatch. Anthropological Monographs
of the University of Idaho no. 3. Moscow, Idaho: University Press of Idaho.
1983 Anatomy and Dermatoglyphics of Three Sasquatch Footprints. Cryptozoology,
Vol. 2: 53-81.
© Susan Cachel,
Department of Anthropology, Rutgers University 1985
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