Pre-hibernation fat and body mass data
The data required to directly assess the spatial variation in body fat
for M. lucifugus prior to hibernation do not exist, so we relied
upon scaling fat mass with spatially-varying body mass. We used body
composition datasets obtained by quantitative magnetic resonance (QMR;
McGuire and Guglielmo 2010) measurements that provided both
pre-hibernation fat mass and body mass information from multipleM. lucifugus populations, including New York, Vermont (McGuire et
al. 2018) and Montana (Haase et al. 2019). We tested for differences in
fat among locations using a linear model with fat as a response
variable. Given that there was no significant difference among
locations, we then fit a linear model with fat as the response and body
mass as the predictor variable to predict fat mass from body mass
(French 1985). This fitted relationship then allowed us to predict fat
mass at locations where we only had body mass measurements. We gathered
additional body mass data from the literature and VertNet (vertnet.org),
in which records were filtered to include only those with geographic
location, body mass, and recorded between September and December (Table
S2, Figure S1).