Lighting requirements of nocturnal primates in captivity: A chronobiological approach
Publication Type: |
Journal Article |
Year of Publication: |
1989 |
Authors: |
Hans G. Erkert |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
activity pattern, aotus, circadian rhythms, entrainment, galago, lemur, light effects, lunar periodicity, masking, microcebus |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/zoo.1430080209.abs From the results of chronobiological studies in 11 Aotus lemurinus (trivirgatus) griseimembra, 3 Galago garnettii, 5 Galago senegalensis, and 6 Microcebus murinus, inferences can be made on the most suitable lighting conditions for nocturnal primates kept in captivity. In each species studied light controls the daily periodic course of activity in a dual way. First, the light-dark (LD) cycle acts as the main Zeitgeber, entraining the endogenous circadian timing system (CTS) to the environmental periodicity. Second, the prevailing light intensity has a direct species-specific inhibiting or enhancing effect, masking the level of activity predetermined by the CTS. Marked inhibition of activity is caused especially by low light intensities during dark-time (D-time), which can also lead to drastically reduced food intake (e.g., in Aotus). Therefore, high-amplitude LD cycles should be applied which guarantee a stable external and internal synchronization of the various circadian rhythms of the organism, with a D-illumination intensity high enough to prevent light-induced impairments of the behavior of the animals. Up to now LD cycles of 12:12 h (100–1,000:0.5–0.01 lx; ≥5,000°K) have proved to be most suitable. Only in Microcebus should the D-illumination be reduced to about 10−4 lx. Moreover, it must be considered that species with a photoperiodically controlled reproduction cycle require specific alterations of the L-time:D-time ratio.