Chronobiology of free-ranging domestic cats: Circadian, lunar and seasonal activity rhythms in a wildlife corridor

Abstract

Among domestic animals, the domestic cat (Felis catus) probably has the highest proportion of free-ranging individuals in the population and as such is an important component (i.e. predator) in ecosystems. Due to their potential impact on wildlife, the management of domestic cats is a hot topic today. However, there are few studies on the chronobiology and activity of domestic cats in relation to natural cycles. Therefore, the aim of our research was to investigate their circadian, lunar and seasonal rhythms. We monitored the activity of free-ranging cats in a selected corridor within an approximately 800 m2 patch of shrubs and trees in an agricultural landscape that is regularly used by wildlife in the surrounding area. Monitoring was carried out for two consecutive years using a trail camera. Data collection was based on video analysis of all recorded video clips (n = 2081 from 732 camera trap nights). A total of at least 15 individuals were identified in the area. Cats were most frequently observed in spring and summer (a total of 70% of all observations). Cats with prey were mostly observed in summer (∼56%) and never in winter. Circadian activity of domestic cats was nocturnal/crepuscular (p < 0.0001) with two peaks of activity, one in the late evening (∼21.00 h) and another in the early morning (∼5.00 h). The appearance of the cats with the prey corresponded to the general circadian activity. Slight shifts in activity due to day length (sunset/sunrise) were observed when comparing circadian rhythms in relation to seasons, especially in winter when there was a pronounced peak in activity in the early evening. For cat activity in relation to the lunar cycle, we found a tendency for higher nocturnal activity around new moon (p = 0.065), with this pattern being significant in spring (p < 0.05). However, the appearance of cats with prey was not related to the lunar cycle. Understanding the circadian, lunar and seasonal activity rhythms of domestic cats is an important prerequisite for developing an optimal cat management strategy that takes into account both welfare aspects (especially natural behaviour) and minimising the impact of domestic cats on wildlife.