34, P < 0.001). In particular, kudus were captured significantly later than impala (Tukey's test, P < 0.001), showing a genuine prey selection related to hunt timing, which would have been overlooked using clock time. These results thus highlight that even at low latitudes (18°S), the truer significances will be lost in noise if clock rather than sun are used to measure find more event sequences. First, all controlled studies (i.e. as opposed to field studies) unsurprisingly indicate the exact variation in the daylight cycle. This may reflect and acknowledge the importance of light as a ‘zeitgeber’. Among the field studies, only 33% used the actual variation of sunset and sunrise to characterize daily activity patterns.

In contrast, 38% of field studies ACP-196 order used clock time and finally 29% divided the study period

monthly or seasonally, leading to difficulties of interpretation of the effect of change in the sun’s position at a set clock time. Consequently, two-thirds of the ‘field’ studies we reviewed could be subject to misinterpretation caused by an inappropriate handling of time data. This is illustrated in Fig. 6, which accounts for the proportion of field studies that used the different measurement methods according to the latitude, duration of the study and taxa investigated. Tropical studies are more likely to use ‘clock time’ probably because changes in sunrise and sunset are seemingly less marked there (χ2, P = 0.001). Yet, two-thirds of the studies conducted between 30° and 60° used

clock time (Fig. 6a). The method used did not differ according to the duration of the study (χ2, P = 0.981), despite the fact that long-term studies are more affected by the change in day length. In all cases, more than two-thirds of the studies failed to record time properly (Fig. 6b). There was a trend for mammal and reptile studies to use the clock time more than studies of other taxa (χ2, P = 0.016). Studies on reptiles, which are poikilothermic animals, would be expected to take account for sun’s position when recording time, but systematically used clock times (Fig. 6c). This short review shows that even if the behaviour is recorded in high latitude, during a prolonged study selleckchem and/or on poikilothermic taxa, a significant number of studies still use clock time, despite the risk of errors and misinterpretation due to changes in the sun’s position. With a mathematical model based on astronomical parameters, we demonstrated that recording behavioural data in the field using the time given by a clock can generate substantial errors compared with the real time of events, as given by the position of the sun in the sky. These errors increase with both latitude and duration of the study. The analysis of African wild dog hunting behaviour data shows that using clock time would have generated a false pattern, suggesting that all three prey species were killed within the same time windows.