Many speculate that Bigfoot is not one breed of animal, but in reality a whole new genus of wildlife.
Where are they found?
The first is the Pacific Northwest Area, which takes in the states of Washington, Oregon, Northern California and western Idaho. In this area Bigfoot is usually described as being between 8-10 feet tall and somewhat shy and elusive.
The second most populous area is the Ohio Valley Region. This includes the states of Ohio, Kentucky, east Tennessee, and western North Carolina. The Bigfoot in this area is usually described as being about 7-8 feet in height. They appear to be much more aggressive, especially toward dogs, than the Pacific Northwest creature.
The third and fourth most populated areas are the Bayou regions and the Everglades of the south This area includes east Texas, southern Arkansas, most of Louisiana, and southern Florida. In this area, Bigfoot, also called Skunk Ape, is usually described as being much smaller. Most witnesses state this creature is only about 5 feet tall. The creature also seems to be less shy than his Pacific Northwest cousin, but not nearly as aggressive as the Ohio Valley Bigfoot.
How are they different?
The different descriptions have led many in the field to theorize there are at least three distinct breeds of Bigfoot. While it is true that Bigfoot descriptions do vary with geographic location, the main difference is usually in size. The different breed theory may very well be a valid hypothesis, but there could also be another reason size varies with region.
Diverse Food Supply
Like humans, Bigfoot size must be closely related to diet. Each area mentioned has a diverse natural food supply and the size differences is possibly a result of the protein sources of the area.
We do know that Bigfoot is omnivorous. From personal observation, I can deduce that, given the choice, Bigfoot would prefer to eat plant based foods, preferably what they can find in gardens and feed storage bins. I do not think Bigfoot prefers to hunt if plant based foods are available.
The Pacific Northwest Bigfoot is by far the largest. The Pacific Northwest Area is also the most remote and the likelihood of raiding grain bins and gardens would seem less possible. They do have the opportunity of harvesting fruits and berries in the wild, but these have a very limited season. Bigfoot will find it necessary to obtain food from animal sources. In order to supply an adequate amount of nourishment, Bigfoot will most likely prey on or scavenge the larger animals. The higher consumption of meat would explain the larger stature .
In the Ohio Valley, at least during the warm months, Bigfoot has a very ample chance of obtaining food by raiding gardens and commercial corn and grain fields. I have taken numerous reports attesting to this very thing. As with most living things, Bigfoot would prefer to take the easy route of obtaining food. From personal observation, I know Bigfoot will pass up easy prey, namely lambs, confined chicks, and young calves. In most cases finding these is a predators dream, but Bigfoot has been observed passing these up in order to feed on grains.
In the colder months, the Bigfoot will have to depend more on hunting, but not to the extent of inhabitants of the Pacific Northwest. The greater consumption of lower fat and calorie plant based food sources is a reasonable explanation for the smaller size of the Ohio Valley Bigfoot, as compared to the Pacific Northwest specimens.
The southern Bigfoot is usually spotted in marshy areas. This area would supply an even greater amount of plant based foods. Due to its milder climate, there is also a longer growing season. Most likely, the diet of the southern Bigfoot is made up almost entirely of plants. In the event meat is consumed, it would come from fish or smaller varieties of wildlife.
Why do they act differently?
In regards to the different temperaments, I think this is solely a matter of environment and chance meetings. When Bigfoot does show hostile tendencies, the hostility is usually directed at dogs. The very survival of Bigfoot is based on its ability to move about silently and undetected. This would be an impossible feat whenever dogs are in the area. Nothing can move silently with a pack of dogs nipping at its heels. In order to maintain stealthy movement the dogs would have to be discouraged from barking or otherwise silenced.
The Ohio Valley would have a much larger dog population than other Bigfoot regions, and a much greater chance of encounters. The Ohio Valley Bigfoot is inherently no more aggressive than any other. They are just placed in more precarious situations that affect the chances of survival, thus must show a more aggressive side.