Bigfoot Encounters

North American Bipedal Primates

Basic Physiology and Biology of the animal in question

Douglas E. Trapp

23 January, 2006


From my beginning years as a child (1967) with an interest in anthropology, I’ve examined much of the reports in print; studied several excellent scientific papers; discovered and had analyzed prints by a scientist; interviewed witnesses; became fluent in wildlife biology and several other disciplines including primatology and anthropology; and developed an understanding that I think is most likely correct for the animal commonly referred to as Sasquatch, or Bigfoot. This collective research term has accounted for approximately 39 years of my life, although I claim activity in this realm of scientific examination dating back to 1976 (30 years). In this document I refer to these animals as “bipedal primate(s)” for the reader. Occasionally I loosely use the term “primate(s)” to describe anthropoids, and I hope the reader understands that unless I use the term “human”, I am not referring to such. Humans are primates as well are bipedal primates, although humans are referred to as “humans” in this text.

Although this animal is not scientifically identified, to date, the supportive evidence and related scientific scrutiny has offered many clues regarding their physical, anatomical, biological, and general nocturnal lifestyle that has apparently eluded scientific discovery (no bones or body) for eons. I submit here that this collective evidence and scientific examination, although limited, supports the existence of a bipedal primate in North America of which said population size cannot be determined. The mystery here is only, in my mind, that very few people or scientists accept the evidence to support this animal’s existence. In this brief paper I describe some basic characteristics for this animal that may be useful for those who desire searching for further evidence. Although some of this is written as if it were fact, please understand that it is only my personal understanding that is being expressed here, and until we have bones or a body and scientific examination of such, nothing I say is fact relating to this animal. I am sure some of my theories will turn out to be fact, but until then, it is not. With hard work and a lot of good luck, I hope someone is successful in proving me right.

General Appearance

North American bipedal primates are about twice as large as a human in girth, ranging in height from about 7 to 9 feet tall (average witness heights). Girth is normally appropriate for the height, but some thin individuals are reported. Estimated weights range from 400 to 1000 pounds. They are completely hair-covered except for the face below the brow and above the upper lip, palms of the hands, and the base of the feet. Normal hair cover is dark brown or black. They almost always walk bipedal, or stand erect in one location before walking off erect. Eye color is not normally reported due to the general distance from the witness, but when it is the eyes are usually dark brown or black in color. Eyes are reported to illuminate against headlights and flashlights. The shoulders are normally aligned with the jaw, creating a neck-less appearance. The arms are longer than those in the human and reach to the knees, and are swung to and fro during locomotion. In locomotion the knees appear locked, and do not fully swing out in every step as in humans. Each foot is placed flatly and firmly in the ground rather than the commonly known “Heal-to-toe” aspect of the human. In general, these are very large hair-covered bipedal primates who can motivate through very rugged terrain with ease.


Extremely muscular in appearance, these animals show distinct and strong buttocks/thigh muscles, as well as very strong shoulder muscles. The neck bones are apparently limited and disallow head turning to an extent where the upper torso must twist during locomotion in order to look to the side or behind, or the whole body must otherwise change position in a stance. From legitimate footprints it has also been indicated that they also possess a mid-tarsal break in the center of the foot, indicating a shift of the heal bone to a more forward position than that in humans. This “break” is likely used as a tool to grip the rough surface in forested and rocky terrain, thereby allowing mobility in a basically easy manner. The arms are longer than humans to help maintain the upright mobility through difficult terrain, and can be used to assist in climbing steep inclines. The toes can splay open or closed to assist in such mobility, especially in wet or muddy situations, unlike human toes. The hands, from the little evidence collect for such, are very unlike a human hand, with no opposable thumb of which almost appears to act as an additional finger, of sorts. The hands are built for digging deep into soil for roots and grubs, or otherwise to assist movement through thickly wooded areas. The eyes are designed for nocturnal vision, but can see in daylight just as well. The reflection of light in the eyes indicates this nocturnal vision ability commonly noticed in other nocturnal animal life. The hair cover serves two purposes … to maintain body heat in cold conditions, and to allow heat dissipation in hot conditions … similar to other large primates. Male genitalia is not noticeable, as is also true in all other large primates. Female genitalia is never reported, although large breasts are reported in adult female observations, especially in wilderness areas. Sex differentiation is not easily distinguished in most cases because of the witnesses inability to get a close look at details. Most of the obvious female observations have been reported from remote wilderness areas, or a surprise encounter in simi-remote wilderness. Most sightings are assumed to be of male individuals because of the witnesses’ inability to view sex differentiation in the subject. Both male and female are extremely large in girth compared to humans, and fit the same basic description by the observer, other than obvious breasts.


The choice habitat is primarily thickly wooded and/or forested zones in North America, accompanied by rivers, streams, or creeks. Priority are areas away from human activity (i.e., away from human communities). Normal habitat altitude is between 2,000 and 4,000 feet above sea-level in remote zones. Such habitat is likely used for breeding and raising young. Secondary habitat includes thick woods and/or forests near water (of any sort, including ocean shoreline). Bipedal primates observed in “open” terrain are likely moving from one habitat zone to another … usually nocturnally. Such described habitats (collectively) exist from about 65 degrees north latitude, south to about 25 degrees north latitude (tip of Florida). The primary habitat zone, however, appears to be generally located in the Pacific Northwest wilderness areas from Central California, north through the Oregon and Washington Cascade range, extending into the Olympic Peninsula (Washington); Skamania County, Washington in particular; remote regions of Idaho; and throughout much of British Columbia, Canada.


It appears that the young males move about throughout North America, some distant, and some close to the natal area. Females, however, do not appear to wander away from the natal area for any great distance (probably not more than within a 100 square mile zone). The young males are often the culprits of nighttime garbage raids and other human observations reported within human communities. These observations have been reported in every U.S. State and every Canadian Province from the time of the first Europeans to date. This activity is nomadic and normally results in only a few reports over a short period of time in one given area. It is likely that these young males eventually wander back to their natal area, or the same general area of their birth, later to locate mates when they become adult. Although these are juveniles, they are very muscular and normally larger in height and girth than a human (6-7 feet tall, 250-450 lbs weight). It is only assumed that these are all male wanderers, based on the lack of “breast” reports for the same associated incidents.


This occurs only in remote wilderness areas. Although young males may vocalize in other zones during their movement transition, the mating can only be done where females can be found … wilderness zone areas. Mating vocalizations are described by many wilderness witnesses (backpackers and field biologists), and are generally described as a long, deeply toned moan that echoes through the valleys. Upon locating a mate, the male apparently stays within a certain territory until the young are reaching a stage of maturity, and does not vocalize. The females, however, remain in the same zone throughout life, and once the young leave the female she is ready to breed again. This is a very slow cycle that does not help to increase the population of bipedal primates, but only helps maintain its size and genetic diversity.

The Young

The female and male help raise the young for the first few years. The adult female provides milk to the young until weaned, like all mammals. The actual growth rate of young bipedal primate is unknown, but based on other large primates it is likely faster than that of a human. In other words, a 6 year-old male or female may be considered a teen-ager (5-6 feet tall), while adulthood may occur as early as age 8 (7-9 feet tall). This would make it feasible and likely that the adult female who produced the young would mate once every 6 to 8 years. The young are maintained throughout adolescence by both parents. Growing at such a fast rate shows the young feeding omnivorously (weaned) at about 1 year of age, and likely bipedal before that time as well. At some point, a young female may become attractive (in estrus) to the adult male, and he is thereby chased away by the adult female. The young male may also desire his own mother (in estrus) and be chased away by the adult male. The latter is the most likely scenario. Such behavior is characteristic of most large primates. It is not likely that an adult female will have twins, or consecutive births where brother and sister are together, although this has been rarely reported by some witnesses. It is possible that in such circumstances the extra juvenile was an adoptee. If such were the case, the young male may be attracted to the young female, and be chased off by the adult male and/or female. Females of whom become adult stay in the same general area, while males normally wander about for probably two or more years before returning as adults.


Normal behavior for bipedal primates is nocturnal, so most is not easy to observe. Based on other large primates, such as Orangutan, behavior can be suggested in conjunction with eyewitness reports in commonality with unknown primates. Of course the most common behavior witnessed is movement away from the observer in a quick and smooth locomotion. Young males appear to be curious of human behavior, however, and these are the most commonly observed. These individuals are not extremely tall (up to 7 feet), nor are they extremely bulky (about 250-350 lbs), but they display some behavior that is common among young orangutan and other large primates. Generally, they are curious, and stick their nose where they should not. Normally this occurs late at night in areas where most humans do not reside, so safety is always their concern. These young males have shown aggressive tendencies such as rock-throwing, wall-pounding, glass breakage, trash barrel tossing, or simply emitting a high-pitched scream sure to scare the wits out of any common folk. Some have been known to chase vehicles down remote roads at night. Generally, however, their behavior is unknown, other than the fact that they are almost strictly nocturnal, and will vocalize at dusk and dawn, or whenever they feel it necessary. Campers have collectively reported that these animals appear drawn-in to their campfire, standing away within view, quietly standing in awe. These are likely adults or sub-adults. Most behavior must involve food gathering, however infrequently and un-witnessed, as described below.

Food Gathering

Bipedal primates in North America obviously have a wide variety of food sources available. Fruits appear to be the most attractive to them, when available, and that includes human raised crops. Fruits offer enough nutrients to keep a large animal alive for a long time, and humans have known this for eons of time. Many large primates eat fruits alone, and live a comfortable life. North American bipedal primates are opportunistic in food gathering, so depending on the current environment of which they reside, they will eat whatever is edible. Fecal samples have shown a wide variety of consumables with analysis, most of which have included roots, bark, pine cones, grubs, insects, insect larvae, small mammals and unidentified flesh. They are often reported by Native Americans as the theft of fish, hung out to dry, and sometimes taking fish from their nets in streams and rivers. There have been several reports of bipedal primates stealing deer carcasses, although the reports of them chasing-down deer on-the-run cannot be verified. They have been witnessed hunting and killing squirrel and marmot on several occasions. One factor remains … there is no lack of food for such a large primate in any wilderness zone or water-based habitat. These animals can be considered omnivorous based on that fact alone.


Most people, even researchers, ponder the idea of origin when it comes down to bipedal primates in North America. This is still a mystery, but we have evidence to indicate that we are dealing with a highly adapted form of the “Extinct” ape known as Gigantopithecus. In the days of that species, they were living in China, about 100,000 years ago. At the same time there was an animal known as Paranthropus which is thought to be one of our common ancestors. Paranthropus was aggressive, and Gigantopithecus kept moving away from them. As the latter did so, it moved across the Bering Strait, at that time forested, to North America. Paranthropus evolved and became us later, but Gigantopithecus was here long before humans arrived. Gigantos had to evolve to survive, and learned to eat whatever was available. As other animals migrated over, and some died, Giganto learned to consume flesh. Originally a bamboo feeder, Gigantopithecus learned to survive, and as humans began to enter North America over the land bridge, Giganto learned to be secret, and stealth. Their populations were probably very high at some point, but as Native American legends indicate there were many battles against them. Humans had tools to fight with, Gigantos did not. They could only hide, and realizing through time that humans are diurnal, they became nocturnal. Of the Gigantos that survived, only those nocturnal and omnivorous did so. As more humans developed more land, Gigantos hid in the deeply forested areas, now in a major concentration in the Pacific Northwest. Many areas in this zone cannot be occupied by humans, and there are other areas of North America where this is true as well. Although the current Giganto population is smaller than it was originally, it is thriving in areas where most people never wish to look.


I am only one person with one opinion, and I often find myself fighting the opinion of others. The News Media is my worse enemy because they love to make fun of this subject, as if we are searching for fairies or dragons. I will refuse interviews with the News Media unless I find something totally significant (i.e., bones, body) that can support the existence of bipedal primates in North America. In fact, most of those who solicit media attention with this subject are either absolute neophytes, totally naïve, idiots, or want to have their most recent book acknowledged. I really don’t think serious researchers, investigators, or like-minded scientists should waste their time with the News Media or any public scrutiny unless they find something totally significant. That means that we must find a Giganto body or bones, here in North America, no matter how old carbon-14 indicates, to show the world that these animals are real. Personally, I have no idea why the current evidence is unacceptable, especially when we accept the data from Space Probes and Robots and Telescopes in our current world of “facts”. We have more evidence that bipedal primates in North America exist than we do of God himself … so how does that compare? Only the News Media will know the answer to that one.

© Douglas Trapp
Dallas, Texas

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