This guide is not an attempt to bash those who do believe but is an attempt to highlight the problems with the idea of Bigfoot existing.
Also, for the purpose of this breakdown I will be using the most common theory, which is that Bigfoot is an ape or hominid.
I will begin by looking at how a species such as Bigfoot is commonly assumed to have evolved and highlighting the problems regarding this.
The two main ideas are that Bigfoot is a descendant of Gigantopithecus, or more closely related to man, putting it within the Hominid bracket.
Gigantopithecus: Does roughly fit the sizes as commonly reported as that of Bigfoot, of around 7ft - 9ft tall and weighing around the 1000lb mark.
The Problem with this: It is commonly held that Gigantopithecus was a quadruped, which if true Bigfoot would also most likely be a quadruped. The reason for this is that bipedalism usually only develops within small species, it is only after bipedalism has become established that the species can then increase in mass.
Large Theropod Dinosaurs such as T.Rex are a good example of this. Although T.Rex may have been one of the largest Theropod Dinosaurs to live, it was its much smaller ancestors that evolved bipedalism. Once established this would allow the following species to increase in size as each generation evolves measures to deal with the increasing mass being exerted on the limbs.
A 1000lb Gigantopithecus going from a quadruped to biped would just not be practical as each leg would have to support twice as much weight as before, severely hampering movement and cause excessive wear on the legs. An example can be seen in those who are bedridden with morbid obesity as their legs are not capable of supporting the mass of their bodies.
Hominid: This would solve the problems with developing bipedalim as if Bigfoot was a Hominid bipedalism would already be the established form of locomotion which would allow for increase in mass over time.
The Problem with this: Neanderthals,Homo Erectus and Homo Heidelbergensis are three commonly mentioned Hominids in regards to Bigfoot as well as occasionally older species such as Paranthropus. The difficulty here lies in that we have a fairly good idea of what the first three looked like, all of which were very Human in appearance. As for an older species such as Paranthropus, they do superficially resemble Bigfoot, apart from size, but like all non Human Hominids not a single species has been uncovered in America.
Bigfoot is predominately sighted in the Pacific Northwest of the U.S, generally in wooded areas but has been sighted in almost every other state of America as well as Canada, again in mostly wooded areas.
The Problem with this: Species that live in forested areas are usually smaller than those that live in open terrain. For example the African Forest Elephant is smaller than its open country counterpart. This is because size hampers movement through woodland. Also a tall biped would have a higher centre of gravity reducing an animals stability whilst traveling through potentially uneven terrain.
Another problem with the habitat of Bigfoot is that no Apes are found in temperate forests within the northern hemisphere and their has never been any fossils uncovered to suggest the existence of any form of Ape in America.
Although it is possible convergent evolution could have occurred within the New World Monkeys to produce an Ape-Like species, which then migrated to North America during the Great American Interchange. But again we would be expected to find fossil evidence of this occurring as well as wondering why it would become extinct in its original territory, etc.
There are three options available regarding the diet of Bigfoot, Carnivorous, Herbivorous and Omnivorous.
Problem with being a Carnivore: If Bigfoot was Carnivorous then it would be the only Ape or Hominid known to only eat meat. It would also be limited to eating fresh meat as Apes and Hominids do not have a sufficient digestive system to counteract the harmful toxins found in rotting meat.
Limiting Bigfoot to only fresh meat would mean it would have to hunt and due to its size it would have a much higher calorific intake than a Human. One of the main problems I see, is that carnivores are generally opportunistic which would lead to reports of livestock being killed by a Bigfoot for example, as well as bringing it in to competition with other predators. The species would also struggle due to being hampered by its inability to consume rotting meat.
Problem with being a Herbivore Bigfoot being a Herbivore is a much more plausible idea, yet still poses problems. Plant matter is generally poor in nutrients which leads to Herbivores having to spend long periods of time eating. This would suggest a lifestyle similar to that of Gorillas confining Bigfoot to a home range of no more than a few miles which would increase the likelihood of discovery as if one Bigfoot was sighted then the others wouldn't be too far away.
Problem with being an Omnivore Out of the three being an Omnivore is the most likely diet as it is the most varied and fits closer to the diet of most Apes and Hominids. The problem here lies in that Omnivores are just as, if not more opportunistic than Carnivores and this poses the question as to why Bigfoot is not sighted as regularly as other Omnivores in urban areas. You also again have the problem of hunting and why livestock are not reported being killed, etc, and if the species uses rudimentary tools, why has no evidence of this been produced.
If we look at the most likely scenario regarding diet and assume Bigfoot does indeed live within wooded/forested areas as is most commonly reported we would be looking at a large, Omnivorous, mammal.
The Problem with this This would place it well within the niche currently occupied by the Black Bear, especially within the Pacific Northwest. It would also mean Bigfoot would most likely be viewed as a possible food source by Pumas, especially the young and weak. Due to this there would surely be evidence, in the form of carcasses, of young or weak Bigfoot being preyed upon by Pumas.
Also, due to the clash of niches with the Black Bear there would be evidence of violence between the species as is seen between Hyenas and Lions. As Bigfoot is alleged to be an Ape or Hominid, therefore meaning it would be a social species, would give it a distinct advantage over the Black Bear, thus reducing the Bears numbers and range, which is contrary to the current trend as Black Bear numbers are steady increasing.
This is also not taking into account possible interactions with Brown Bears and Wolves, who although occupy slightly more open country, could still encounter a Bigfoot.
These reasons and more lead me to believe that Bigfoot does not exist.
That is my take on the situation, which I have tried to come at as logically and unbiased as possible and I just hope it gives people a few things to ponder on, skeptics and believers alike.
I know I haven't tackled every area, such as population levels, etc but then I don't want to be here forever.
Edited by grendals_bane, 25 January 2012 - 11:00 PM.