Abstract
It has been suggested that the American black bear (Ursus americanus) may be responsible for a significant number of purported sightings of an alleged unknown species of hominid in North America. Previous analyses have identified correlation between ‘sasquatch’ or ‘bigfoot’ sightings and black bear populations in the Pacific Northwest using ecological niche models and simple models of expected animal sightings. The present study expands the analysis to the entire US and Canada by regressing sasquatch sightings on bear populations in each state/province while adjusting for human population and land area in a mixed-effects model. Sasquatch sightings were statistically significantly associated with bear populations such that, on the average, one ‘sighting’ is expected for every 900 bears. Based on statistical considerations, it is likely that many supposed sasquatch are really misidentified known forms. If bigfoot is there, it may be many bears.
Introduction
The United States and Canada feature nearly 20 million square kilometers of land, hosting hundreds of mammal species in its woodlands, prairies, boreal forests, and along its coasts (Kays and Wilson, 2009). Proponents of ‘hominology’ argue that the North American faunal catalogue is incomplete, and that these lands harbor a hominid species as-yet unrecognised by science (Heuvelmans, 1986).
Reported sightings of these alleged animals, variously dubbed ‘sasquatch’ after West Coast First Nations tradition, ‘bigfoot’ to Westerners, and the nomen dubium Gigantopithecus canadensis (Heaney, 1990), number in the thousands (Bigfoot Field Researchers Organization, 2023). Consequently, this anthrozoological phenomenon has entered popular culture.
Numerous casts and photographs of tracks and footprints attributed to sasquatch have been presented (Napier, 1976, ‘Tables’), some apparently featuring primate-like dermal ridge patterns, sweat pores, and sole pads (Cachel, 1985; Krantz, 1983). These have been criticised as hoaxes (constructed with modelling clay and the ‘latex-and-kerosene expansion method’ of preserving details of [human] footprints while greatly increasing their size (Baird, 1989; Bodley, 1988)), including misinterpretations of casting artefacts such as air bubbles (Freeland and Rowe, 1989).
The ‘Patterson-Gimlin film’ is a notorious 16 mm motion picture purportedly depicting an unknown hominid over six feet tall in California (Discovery, 2022; Kelsey, 2022; W Munns, 2014). The film apparently was not spliced or edited (B Munns and Meldrum, 2013), but many have noted the imposing likelihood that the film subject is a suited actor.
Genetic and microscopic analyses of supposed hairs, faeces, and other specimens attributed to sasquatch have been variously identified as synthetic fiber (Somer, 1989; Winn, 1991), or material from known forms such as cervids, bovines, and ursids (Bryant and Trevor-Deutsch, 1980; Coltman and Davis, 2005; Federal Bureau of Investigation, 2019; Hart, 2016a,b; Sykes et al., 2014).
Indeed, the American black bear (Ursus americanus) has been identified as a likely candidate for many purported sasquatch sightings, since the black bear is a large tetrapod, typically covered with a dark pelage, and is known to ambulate bipedally (Nickell, 2013).
Blight (2005a,b) examined the relationship between sasquatch sightings and black and brown bear (U. arctos) populations in the Pacific Northwest (including Alaska, Montana, Oregon, Washington, Northern California, and Idaho) with probabilistic models of expected animal sighting rates. No positive correlation between brown bear population density and sasquatch sighting frequency was not found, suggesting that brown bear misidentification must comprise only a small proportion of all sightings. However, a positive correlation was identified for black bears, which further implicates the black bear in sasquatch ‘sightings’. Lozier et al. (2009) compared results from ecological niche models both for sasquatch and for black bears in the Pacific North-west, noting a high degree of overlap in predicted distributions.
In a previous article titled “If it’s real, could it be an eel?”, the author used statistical methods to investigate whether large Anguilliformes may account for the related anthrozoological phenomena at Loch Ness (Foxon, 2023a). In the present study, statistical methods are used to investigate whether purported sasquatch sightings may be explained in large part by mistaken identifications of black bears.
Material and methods
Numbers of sasquatch sighting reports in the US states and Canadian provinces were sourced from the Bigfoot Field Researchers Organization (2023) Geographic Database of Bigfoot/Sasquatch Sightings & Reports. These data consist of eyewitness testimonials, mostly from the second half of the 20th century to the present.
Black bear populations for the US states and Canadian provinces were taken from Hristienko and McDonald (2007), except for Delaware, Hawaii, Illinois, Indiana, Iowa, Kansas, Nebraska, North Dakota, and South Dakota, which have no known breeding populations of black bear and so were coded to zero, and for Alabama (Byington, 2020), Connecticut (Connecticut Department of Energy Environmental Protection, 2020), Kentucky (Estep, 2020), Louisiana (Kemker, 2021), Maryland (Maryland Department of Natural Resources, 2020), Mississippi (Young and Mississippi Department of Wildlife, Fisheries, and Parks, 2021), Missouri (Missouri Department of Conservation, 2021), Nevada (Wildlife Conservation Society, 2020), New Jersey (New Jersey Department of Environmental Protection, 2022), Ohio (Ohio Department of Natural Resources, 2022), Oklahoma (Godfrey, 2021), Rhode Island (McLeish, 2022), and Texas (Rasmussen, 2022), which were sourced variously from state department resources, conservation societies, and biologists and conservationists quoted in media articles. Where ranges were given (e.g., 40–50 bears), the midpoint was taken (i.e., 45 bears).
The latest available human population statistics and land area figures for the US states and Canadian provinces were obtained from the United States Census Bureau (2022, 2023) and Statistics Canada (2022a,b), respectively. A geojson map of the US and Canada was sourced from Cartograhy Vectors (2022).
The possible association between sasquatch sighting reports and black bear populations across states and provinces was first investigated by calculating the Pearson correlation coefficient between these two variables in an unadjusted analysis.
Sasquatch sightings are logically a function of the number of people in each state/province available to make a sighting, and the size (land area) of each state/province (because interactions between hypothetical sasquatches and humans are probably less likely when both populate an area sparsely). Consequently, a model was implemented which investigated the possible association between sightings and bear populations while also adjusting for the potential impact of human population and land area. This was a linear mixed-effects regression model which regressed the number of sasquatch sighting reports in each state/province on the black bear population, human population, and land area of each state/province. The model was given by
where SSR is the saquatch sighting reports vector, X is the design matrix of predictors (bear population, human population, and land area), β is the fixed-effect regression coefficients vector, Z is the design matrix of random effects (the states/provinces), u is the random effect coefficients vector, and c is the residuals vector. Interaction terms were considered but these effects were not statistically significant (p > 0.05) and/or provided poorer model fits to the data as measured by the log-likelihood, therefore interaction terms were not included in the final model. The restricted maximum likelihood (REML) estimator was used for unbiased variance estimation, as sample size was low.
All analyses were performed in Python 3.8.8 with the packages Numpy 1.20.1, Pandas 1.2.4, Scipy 1.6.2, Statsmodels 0.12.2, and Plotly 5.11.0. All code and data are available in the online Supplementary Information (Foxon, 2023b).
Results
Figure 1 shows choropleth maps for the number of sasquatch sightings, black bear populations, and human populations in the United States and Canada. The human population and sasquatch sighting maps are most similar, which is logical because more people means more potential encounters with any North American species. Both the sasquatch sighting and black bear population maps are strongly coloured in the Pacific Northwest area, though black bears are not prominent in Texas and Florida, where alleged sasquatch sightings have been reported.
Choropleth maps for sasquatch reports, black bear (Ursus americanus) populations, and human populations in the United States and Canada.
In the unadjusted analysis, the Pearson correlation coefficient between number of sasquatch sighting reports and black bear populations in states/provinces was low and statistically non-significant (ρ = 0.0607, p = 0.642).
However, in the fully adjusted regression analysis which controlled for confounding by human population and land area, black bear population was significantly associated with sasquatch reports such that, on the average, one sasquatch sighting is expected for every 900 black bears in a given state or province (Table 1).
Regression Model Results
Discussion
The present study regressed reports of sasquatch sightings on black bear (Ursus americanus) populations across the US and Canada. A significant positive association was found between sasquatch sightings and black bears such that, after adjusting for human population and land area, one sasquatch sighting is expected for every 900 bears in a given state or province.
These findings are in agreement with the results of previous studies by Blight (2005a) and Lozier et al. (2009), and suggest that many supposed sasquatch sightings in North America are likely misidentified black bears. The present study builds upon previous analyses by expanding the area under consideration from the Pacific Northwest to the entire US and Canada, and by investigating quantitative associations with a mixed-effects model.
Limitations include potential residual confounding by effects such as homeless populations who may also be misidentified, as well as mismatching years in the data (e.g., while the bulk of the black bear population estimates were for 2001, others were more recent). Notably, sasquatch sightings have been reported in states with no known breeding black bear populations. Although this may be interpreted as evidence for the existence of an unknown hominid in North America, it is also explained by misidentifiation of other animals (including humans), among other possibilities.
In conclusion, if bigfoot is there, it may be many bears.
Fundings
This work was not supported by any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of interest disclosure
The author declares that they have no financial conflicts of interest in relation to the content of the article.
Data, script, code, and supplementary information availability
Data and code are available online: https://doi.org/10.17605/OSF.IO/AV3G2
