According to monthly live-trapping records, the body mass of
free-ranging female raccoons increased from 3.6 +-0.6 kg during summer
to 5.6 +-0.8 kg in early winter, and the mass of free-ranging males
increased from 4.0 +-0.5 to 6.7 +-0.9 kg during the same interval. These
seasonal changes in body mass were due to fluctuations in the amount
of body fat and represent a mechanism for storing energy during fall
for use in winter. In summer, captive and trapped male and captive
female raccoons had the same body mass (4.73 +-0.61, 4.41 +-0.70, and
4.67 +-0.88 kg, respectively, Table 2). Mass of captive females did
not change between seasons, whereas captive males were heavier in
winter than summer (p<0.005; Table 2). This seasonal change in mass of
our captive males was of a much smaller magnitude (0.6 kg) than that
observed for wild males (2.7 kg). During winter, captive males (5.34
+-1.39 kg) were heavier than captive females (4.49 +-0.98 kg; p<0.005;
Table 2). Thus, our captive animals maintained a body mass throughout
the year that was intermediate to the range of values found for wild
raccoons in the same area.
TABLE 2.--Body mass in kg and basal metabolism
(mL O_{2}.kg^{-0.75}.h^{-1}) of _Procyon lotor_
in summer and winter (s.d. = standard deviation
and n = number of observations).
----------------+-----------------------------------------------------
Season and sex | Body mass, +-s.d., (n) Basal metabolism, +-s.d., (n)
----------------+-----------------------------------------------------
Summer |
Trapped male | 4.41 +-0.70 (52) 780 +-112 (20)
Captive male | 4.73 +-0.61 (22) 680 +-102 (8)
Captive female| 4.67 +-0.88 (41) 618 +- 92 (13)
Winter |
Captive male | 5.34 +-1.39 (31) 704 +- 81 (19)
Captive female| 4.49 +-0.98 (42) 667 +-139 (25)
----------------+-----------------------------------------------------