Licht-im-Terrarium: Literaturdatenbank

Simple Summary

 

Visible light is essential for most animals because it controls daily and seasonal rhythms, influences behaviour, sleep, and reproduction, and even affects health and immunity. In the wild, animals are adapted to natural light cycles shaped by day and night, the moon, and the seasons. In captivity, however, animals are often exposed to artificial light that does not match these natural patterns. This can confuse their "internal clocks," disturb sleep, alter activity, and reduce welfare. For example, animals kept in zoo nocturnal houses may experience reversed light cycles so visitors can see them active during the day, while zoo events at night can expose animals to prolonged illumination. Veterinary care can also involve continuous lighting that interferes with recovery. Although some artificial lights can help create safe and attractive environments for visitors, they may not provide the full spectrum of natural sunlight that animals need. New technologies, such as lamps that closely mimic natural light, offer promising alternatives, but their use is still limited. Understanding how different species respond to light and adjusting management accordingly is essential to ensure healthy and natural behaviours. By carefully managing light, institutions that house animals can enhance welfare outcomes and, in the case of zoos and similar facilities, promote education and public engagement. Abstract Light plays a central role in regulating biological rhythms, behaviour, and physiology across animal taxa, yet its management in captive settings remains, relatively, underex-plored. This review synthesises current knowledge on the effects of natural and artificial lighting on vertebrate animal welfare. We briefly outline the physical properties of light and how vertebrates perceive it, emphasising evolutionary adaptations to diverse photic environments. We then discuss how light governs circadian and seasonal cycles, influencing activity patterns, sleep, reproduction, metabolism, immune function, and welfare, with the latter addressed through the lens of the Five Domains model. Special attention is given to the disruptive effects of artificial light at night (ALAN), which can desynchronise biological rhythms, alter behaviour, and impair reproduction in captive species. With a focus on zoos, management practices, such as reversed light cycles in nocturnal exhibits and illumination during public night events, are critically examined in terms of their welfare implications. We highlight both the risks and potential benefits of artificial light technologies, including full-spectrum and spectrally adjusted systems, for creating environments that more closely mimic natural conditions. Finally, we identify knowledge gaps and propose future research, along with a decision tree, emphasising the importance of species-specific lighting protocols that consider evolutionary adaptations, ecological needs, and welfare standards. Effective light management can therefore play a pivotal role in advancing captive animal welfare.

 

Abstract

Light plays a central role in regulating biological rhythms, behaviour, and physiology across animal taxa, yet its management in captive settings remains, relatively, underexplored. This review synthesises current knowledge on the effects of natural and artificial lighting on vertebrate animal welfare. We briefly outline the physical properties of light andhowvertebrates perceive it, emphasising evolutionary adaptations to diverse photic environments. We then discuss how light governs circadian and seasonal cycles, influencing activity patterns, sleep, reproduction, metabolism, immune function, and welfare, with the latter addressed through the lens of the Five Domains model. Special attention is given to the disruptive effects of artificial light at night (ALAN), which can desynchronise biological rhythms, alter behaviour, and impair reproduction in captive species. With a focus on zoos, management practices, such as reversed light cycles in nocturnal exhibits and illumination during public night events, are critically examined in terms of their welfare implications. Wehighlight both the risks and potential benefits of artificial light technologies, including full-spectrum and spectrally adjusted systems, for creating environments that more closely mimic natural conditions. Finally, we identify knowledge gaps and propose future research, along with adecision tree, emphasising the importance of species-specific lighting protocols that consider evolutionary adaptations, ecological needs, and welfare standards. Effective light management can therefore play a pivotal role in advancing captive animal welfare.

 

Keywords:

 

artificial light; circadian rhythm; zoo husbandry; visual perception; animal welfare; photoperiod; nocturnal behaviour