Cage activity in the Virginia opossum

Abstract

Cage activity of four Virginia opossums was measured twice daily (morning and night) under six levels of ambient illumimr tion (dark, less than 1, 2.5, 5, 25, 50 ft-c). Analysis of variance indicated that the Ss were significantly more active under the three lower levels of illumination than under the three higher ones and were significantly more active at night than in the daytime. In addition the Illumination by Time of Day variable was significant. This interaction between environmental stimuli and phases of the circadian rhythm cycle is discussed in terms of Bindra's hypothesized inverted V-shaped curve relating physiological arousal and performance.

Cage activity in the California antelope ground squirrel

“…However, when the scores of male Ss were contrasted with those of female Ss using the technique proposed by Scheffe (1953), no significant difference attributable to sex was found. DISCUSSION In general, the results of the present study are congruent with those of the opossum study (Cone & Cone, 1968). In both experiments, Illumination, Time of Day, and the Illumination •by Time of Day interaction provided significant sources of variability .…”

“…Sci., 1969, Vol. 17 5Cone & Cone ( 1968) have reported that the effects of ambient illumination on the cage activity of the opossum ( Didelphis virginiana) are not independent of the phase of the organism's circadian cycle. As illumination was increased above a range of 2~ to 5 ft-c, cage activity during• the nighttime ( 10 p.m. to midnight) decreased, while cage activity during the daytime (10 a.m. to noon) increased.…”

Some variables affecting feeding cycles in the opossum

“…A number of investigators have studied the effects of the light-dark (LD) cycle upon activity (Ashby, 1972;D. M. Cone, 1973 Cone, 1968) and upon feeding and drinking behavior (Rusak & Zucker, 1974;Stephan, 1984). Such studies attain great importance, particularly when one considers the implications of their results on learning.…”

Circadian locomotor activity in the Virginia opossum

“…opossum's locomotor activity cycle are comparable to those obtained from other nocturnal mammals under similar lighting conditions. Cone & Cone (1968) demonstrated that Virginia opossums were more active between 10:00 p.m. and midnight than between 10:00 a.m. and noon. In addition, nighttime activity was significantly higher in the dark and under ambient illumination levels of 1 and 2~ fc than it was under illumination levels of 5,25, aq.d 50 fc.…”