The Influence of Moonlight on Activity of Woolly Opossums (Caluromys philander)

Abstract

Activity of four radiocollared woolly opossums (Caluromys philander) showed an inverse relationship between moonlight and both level and duration of the activity period. However, between new moon and half-moon, both measures of activity in females remained low on average, whereas they decreased sharply in males. The influence of moonlight on activity, as well as the general activity pattern in this nocturnal marsupial, are interpreted as anti-predation adaptations. The level of activity seems to be constantly lower, and independent of moonlight intensity, in females of C. philander. Moonlight could reduce activity, not linearly but above a threshold in light intensity, for higher levels of activity reached only in males.