The daily cycle of raccoon T_{b}'s during summer and winter are
presented in Figure 7. In general, T_{b}'s showed a marked circadian
cycle in phase with photoperiod. T_{b}'s rose above 38 deg.C for several
hours each night but remained below 38 deg.C during daytime. During
summer, with the exception of one female whose record was not typical
(Figure 7), T_{b}'s rose above 38 deg.C shortly after sunset, whereas in
winter T_{b}'s did not rise above 38 deg.C until several hours after
sunset. Once T_{b} was elevated it usually remained so until just
before or after sunrise (Figure 7). During summer, T_{b} was above
38 deg.C for 85% or more of the time between sunset and sunrise (87% for
the female with the typical body temperature pattern, and 85% and 98%
for males), whereas in winter it was elevated for only 47%-78% of the
time between sunset and sunrise (47% and 61% for females, and 67% and
78% for males). During night, T_{b} would oscillate between 38 deg.C and
about 39 deg.C, such that two peak values occurred. These peak values
presumably corresponded to two periods of heightened nighttime
activity. During summer, one of these peaks occurred before and the
other after 24:00 hours, whereas in winter both peaks occurred after
24:00 hours. With the exception of one female in winter (Figure 7),
the lowest T_{b} of the day for both sexes was near 37 deg.C, and this
typically occurred during daytime (Figure 7).
$Discussion$