Friday, March 17, 2017

Sasquatch Habitat And Population Size: Some Calculations

While I wrote an article that was skeptical about Sasquatches, as well as Yetis, quite recently, by no means does that entail that I blindly accept all arguments offered by skeptics against the existence of these creatures. One argument that I have been thinking about lately is the argument that, as large mammals require a large home range that is proportional to their body mass, and there is little forest habitat in the Pacific Northwest of Northwestern North America, this means that Sasquatch would have either been discovered long ago, or does not exist, as there is not sufficient forest to allow a breeding population of these creatures to remain hidden until now. This has spurred me to carry out my own calculations to determine how capable the forest habitat of the Pacific Northwest really is of supporting a viable breeding population of these hypothetical animals. Never content to just accept whatever information I read without subjecting it to some critical analysis and skeptical scientific scrutiny, I decided to test this claim made by critics of Sasquatch's putative existence.

The correlation between an animal's body mass and the size of its home range is furnished by the following formula: Home Range = 0.024 * Body Mass^1.38. I was not able to find, in any sources, the answer to the question nagging me: Does this formula refer to the kilometers and kilograms of the metric system, or to the miles and pounds of the imperial system? In any case, as miles are larger than kilometers and pounds are smaller than kilograms, utilizing miles and pounds would have the effect that the area of the home range would be represented by a smaller number, and the mass of the animal would be represented by a larger number. Therefore, this would make the calculated plausibility of Sasquatch lower than if kilometers and kilograms had been utilized in their stead.

Since I am trying to stay as conservative and critical as I can possibly be (for reasons I will state at the end of this post), I decided to plug in the numbers that would render it the least likely that a viable Sasquatch population could exist in the Pacific Northwest, meaning that I decided to use miles and pounds as units. Additionally, while there are varying hypothetical speculations about the body mass of Sasquatch in the literature, I decided to go with 1,000 pounds, reportedly the highest end of the range, according to a Bigfoot research group.

Meanwhile, according to the World Wildlife Fund, also known as the Worldwide Fund For Nature, there are 114,000 square miles of forest in the Pacific Northwest.

I then plugged 1,000 pounds and 114,000 square miles into the equation relating home range to body mass:

HR = 0.0024 x 1,000^1.38
1,000^1.38 = 13,803.8426
HR = 0.0024 x 13,803.8426

HR = 331.29222 m.^2

So I got the result that the home range for one 1,000-pound Sasquatch would be 331.29222 square miles.

Then, I divided this number by the estimated number of square miles of forest in the Pacific Northwest, about 114,000 miles, to get the estimated population of Sasquatches that could inhabit this region.

Pop. = 114,000/331.29222
Pop. = 344.1070826 individuals

My calculated result was that there is a population of about 344 Sasquatches in the Pacific Northwest. Now the question arises: Is even this estimate, which I tried to lowball as much as I could, enough to constitute a viable breeding population of animals? Well, considering the fact that many species and subspecies of large-bodied mammals are currently so endangered that their populations are far smaller than this estimate, the South China Tiger offering just one example, I would say yes. Indeed, according to the Encyclopedia Britannica, a general rule of thumb is that 50 is a minimum number of individuals needed for a genetically viable breeding population. Sasquatch, according to my calculations, would be well over 300 individuals. Whether or not that population is large enough to furnish enough genetic diversity to sustain the population for long periods of time into the future in a world in which the effects of human activity run rampant throughout the biosphere is a different story. Indeed, if Sasquatch exists, it may be that their population was once higher in the past, and has now declined as a result of human encroachment onto their habitats, in which case, if it is ever discovered, it would likely be classified as an endangered species and enjoy the full protection of the law.

And now I come to the reason why I intentionally tried to lowball the estimates as much as I could. And that is to demonstrate that, even in the "worst-case" scenario for Sasquatch's existence/"best-case" scenario for its non-existence, the calculations would still permit a viable breeding population of Sasquatches to exist in the Pacific Northwest of North America. It may very well be that Sasquatch weighs far less than 1,000 pounds, or that this formula is in the context of using metric units of measure, rather than imperial ones (indeed, considering that metric units tend to be far more often utilized as the standard units of measure in the sciences, I think the latter is actually quite likely).

Now, keeping the body mass of the animal constant, I will calculate the estimated viable population size using the aforementioned metric units. In metric units, 1,000 pounds gets converted to 453,592 kilograms, while 114,000 square miles gets converted into 295,258.645 square kilometers.

HR = 0.024 x 453.592^1.38
453.592^138 = 4,636.585077
HR = 0.024 x 4,636.585077
HR = 111.27804185 km.^2

Now, I, once again, divide this number by the area of forests in the Pacific Northwest to get an estimated viable population size.

Pop. = 295,258.645/111.27804185
Pop. = 2,653.3414867 individuals

See how much of a difference that made? Now we have a population of over 2,000 individuals, close to 3,000. This is roughly comparable to what is thought to be the population of remaining wild tigers in the entire world.

So, to recap: Am I a believer in Bigfoot? No. I do not have belief or faith in cryptids, and I go where my evidence, calculations, and logic lead me. And my calculations lead me to the conclusion that, despite the paucity of scientific evidence that withstands the scientific criteria for proving the existence of a given species beyond reasonable doubt, the argument against the possible existence of these creatures from the ecological body size to home range ratio can be safely ruled out.

References/Works Cited:
• du Toit, J.T. December 1990. "Home range – body mass relations: a field study on African browsing ruminants". Oecologia.
• Vath, Carrie L. and Robinson, Scott K. 9 December 2015. "Minimum viable population (MVP)". Encyclopedia Britannica.
• Parker, Edward. "Pacific Temperate Rainforests". World Wildlife Fund/Worldwide Fund For Nature.

No comments:

Post a Comment