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

Domestic animals, especially when reintroduced into natural habitats, inevitably have an impact on native fauna and flora, their diversity and ecosystem dynamics. They compete with native organisms, prey on them, can spread diseases, and hybridise with their wild counterparts. In this respect, the domestic cat occupies a special position, as its population probably has the highest proportion of free-ranging individuals among domestic animals. This refers to feral, stray, farm and other cats that have free access to their habitat, can roam freely and interact regularly with wildlife. Furthermore, the cat was the only animal undergone a double self-domestication in which it has had to express tolerance to other species (humans) and, as a solitary animal, to its own species (Francis, 2015). Nevertheless, the genome, anatomy, and behaviour of the domestic cat (Felis catus) have hardly changed compared to its wild counterpart – the wild cat (Felis silvestris) (Driscoll et al., 2007, Driscoll et al., 2009, Driscoll et al., 2011).

Although considered fully domesticated, it has also retained opportunistic predatory behaviour, whose prey includes birds, mammals, herpetofauna and also invertebrates (Coman and Brunner, 1972, Baker et al., 2008, Herrera et al., 2022). In addition, the domestic cat is very adaptable and reproduces successfully and much more frequently in different habitats and climates compared to the wild cat. Given its predatory behaviour and growing population, the domestic cat is an important predator in ecosystems (Loyd et al., 2013, Doherty et al., 2016, Loss et al., 2022) and has long been considered a threat to wildlife and global biodiversity (Robertson, 1998, Dauphiné and Cooper, 2009, Loss and Marra, 2017, Hadidian, 2021).

In recent years, the stigmatisation of free-ranging, stray/feral domestic cats has increased and the call for their complete control is growing louder. Some argue that the harmfulness of domestic cats is so great that control by any means is necessary (Marra and Santella, 2016). However, even in cases where control is justified, the welfare of cats must always be considered (Slater, 2007).

In order to develop a successful and socially acceptable management strategy for domestic cats and to understand their interactions with wildlife, it is crucial to know their daily behaviour patterns, home ranges, activities, etc. (Harris et al., 1990, Barratt, 1997, Mitchell and Powell, 2004, Deak et al., 2019, Bennett et al., 2021). By understanding how often and when cats engage in certain activities, we can make better management decisions, taking into account both cat welfare and wildlife health (Bekoff and Mech, 1984, Hernandez et al., 2018).

Studies on the outdoor activities of domestic cats are relatively scarce, although this knowledge is crucial for identifying best practices for domestic cat management that reduce the potential negative impacts of cats on wildlife and promote animal welfare. On the other hand, there is more knowledge about the activity dynamics of wild cats, which is thought to be similar in domestic cats. In general, both wild and domestic cats have been found to have higher crepuscular-nocturnal activity (e.g. Kavanau, 1971; Germain et al., 2008; Goszczyński et al., 2009; Horn et al., 2011; Piccione et al., 2013; Parker et al., 2019; Bennett et al., 2021; Lazzeri et al., 2022), which is related to their highly developed night vision system that enables them to hunt effectively even in extremely low light conditions. Looking at the seasonal activity of cats, it generally increases in the warm seasons after winter, i.e. spring and summer, when the activity of all organisms in the temperate zone, including the cat’s prey, generally increases (Haspel and Calhoon, 1993, Blottner and Jewgenow, 2007, Germain et al., 2008, Goszczyński et al., 2009, Horn et al., 2011, Caravaggi et al., 2018). However, there are no studies on the lunar activity of the domestic cat, but its wild counterpart shows higher activity around the new moon, when nights are darker (Lazzeri et al., 2022).

The aim of the study presented here was to comprehensively investigate the most important chronobiological parameters, i.e. circadian, lunar and seasonal rhythms in free-ranging domestic cats. Based on the timing and frequency of appearance of domestic cats over a two-year period in a selected wildlife corridor, we investigated the rhythms of their appearance and activity and how (if at all) these rhythms are related to circadian and lunar cycles as well as season.

We predicted that i) general cat activity, as well as appearance with prey, is highest at night (darkness); ii) cats are more active in spring; and iii) cats, as animals with excellent night vision, are more active during the darker phases of the lunar cycle (new moon, darkest nights).

Study area and observations

The observations took place from 5 January 2020 to 5 January 2022 in a grove (trees and shrubs) through which an active wildlife corridor ran. The study site/corridor was located in an agricultural landscape in Slovenia, on the edge of the village of Glinje (Braslovče municipality; 46°15'54.80'' N, 15°2′29.96'' E – temperate zone; altitude 293 m; Fig. 1).

Since the study area was a relatively small forest patch, isolated in an arable landscape, which as such is very attractive for the daily

Seasonal cycle

The results on the general appearance in relation to the season (Fig. 2) showed the highest frequency of appearance in spring with 39.2% of all recorded observations. The appearance of cats then gradually decreased over the seasons and in winter was less than 10% of all recorded observations (9.1%). The distribution of cats with prey by season differed significantly from the general distribution. Cats with prey were most frequently observed in summer (55.9%), the rest of the observations were

Chronobiology of the cat

The activity of domestic cats shows a certain chronobiological dynamic which, as we have found here, is influenced, at least to some extent, by circadian, lunar and seasonal cycles. Domestic cats have been shown to be nocturnal/crepuscular, exhibiting bimodal activity with peaks in the late evening and early morning, which is consistent with previous findings on domestic and wild cats. However, wild cats appear to be more markedly nocturnal (Germain et al., 2008, Lazzeri et al., 2022), with the

Conclusions

In summary, free-ranging domestic cats show activity patterns that correspond well with the circadian, lunar or seasonal cycle. These quite distinct patterns can therefore be taken into account when designing cat management that does not compromise domestic cat welfare, wildlife existence and ecosystem function. In conclusion, however, it should be noted that only one study site was observed with a camera and that despite the long-term (two years) continuous observations and the large number of

Funding

Declaration of Competing Interest

The authors declare no conflict of interest.