footprint photographs were originally cast by Primate Anatomist Dr.
Jeff Meldrum of Idaho State University in 1996, in the Blue Mountains
near the Umatilla National Forest, right outside Walla Walla, Washington.
The isolated trackway consisted of 40 plus footprints. Dr. Meldrum analyzed
the trail and found that the tracks had proceeded out from a remote
drainage, went down a muddy farm road, across a plowed field, continued
along an irrigation ditch and back into the woods.
Other clues were found in the trail of footprints... At one point, the
animal that made the tracks had been spooked by something, turned and
walked back, looking to the right every other step. It then increased
stride and went up an incline, leaving a few 'half tracks'. From there
the tracks crossed the field towards a brushy area. The tracks were
fresh and some dermatoglyphics were visible, but rainy conditions quickly
washed them away. The footprints showed variations in toe position which
were consistent with the estimated speed of the animal and the different
irregularities in the substrate. The tracks measured approx. 13 3/4"
long by 5 1/4" wide. Step length (not stride) ranged from 3.25-4.25
Meldrum found to be the most interesting observation in this trackway
was the evidence of great flexibility in the midtarsal joint. Several
footprints showed this midtarsal break, (flexed at midfoot) and therefore
created "half tracks".
Other examples of half tracks have been found in California - Blue Creek
Mountain Road, 1957, Washington - Grays Harbor County, 1982, there were
examples of a midtarsal break in some of the tracks at the Patterson
filmsite to, as well as other areas.
The second photograph
is a footprint that showed the midtarsal break. It also has another
interesting features; toe slide-ins. This footprint was found going
up an incline and because of muddy conditions the foot had slipped back
leaving toe slide-ins.
The reason only half of the foot registered is that the heel was elevated
upon impact (presumeably flexed at midfoot). The proportions of this
half track agreed with the full-length tracks. Without toe slide it
measures about 8" long and is slightly over 5 1/4" wide.