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. 2011;6(7):e22285.
doi: 10.1371/journal.pone.0022285. Epub 2011 Jul 20.

Fear of darkness, the full moon and the nocturnal ecology of African lions

Craig Packer  1 , Alexandra Swanson, Dennis Ikanda, Hadas Kushnir
Affiliations

Fear of darkness, the full moon and the nocturnal ecology of African lions

Craig Packer et al. PLoS One. 2011.

Abstract

Nocturnal carnivores are widely believed to have played an important role in human evolution, driving the need for night-time shelter, the control of fire and our innate fear of darkness. However, no empirical data are available on the effects of darkness on the risks of predation in humans. We performed an extensive analysis of predatory behavior across the lunar cycle on the largest dataset of lion attacks ever assembled and found that African lions are as sensitive to moonlight when hunting humans as when hunting herbivores and that lions are most dangerous to humans when the moon is faint or below the horizon. At night, people are most active between dusk and 10:00 pm, thus most lion attacks occur in the first weeks following the full moon (when the moon rises at least an hour after sunset). Consequently, the full moon is a reliable indicator of impending danger, perhaps helping to explain why the full moon has been the subject of so many myths and misconceptions.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Moonlight and lion behavior in the Serengeti and Ngorongoro Crater.
Luminosity is the average proportion of the moon's surface illuminated on that night; vertical lines indicate standard errors. A Females (circles) had larger belly sizes and hence consumed more meat on days nearest the new moon (P<0.0001, n = 7,683 sightings); males (triangles) showed a similar pattern (P<0.0001, n = 3,827 sightings). B. Lions were more likely to make a daytime kill (diamonds) or scavenge (squares) on days nearest to the full moon (P<0.0001 for both). Regression lines are based on the raw data for each respective measure and are only presented to provide a visual guide to the overall trends; statistical analyses are presented in Tables S1, S2, S3, S4, S5, S6.
Figure 2
Figure 2. Lion attacks on humans in Tanzania.
Bold text shows the number of attack events in each district (1990–2008) ; italics indicate the number of victims with known attack times (1988–2009).
Figure 3
Figure 3. Number of humans attacked by lions each hour across the lunar cycle.
Rows indicate the days of the lunar cycle; columns represent time of day between 18:00 and 05:00. Brightness of each cell is proportional to percentage of the moon's illumination. Grey cells with italic font indicate the number of attacks when the moon was above the horizon; black cells with bold font indicate attacks when the moon was below the horizon; several cells have two numbers because of the varying times of sunset/sunrise over the course of the year. Yellow bars indicate dawn (min. 5:55 AM, med. 6:16 AM, max 6:36 AM) and dusk (min. 18:13 PM, med. 18:26 PM, max. 18:48 PM). Red boxes enclose days of the lunar cycle that were significantly over-represented in each hourly distribution according to Dmax of the Kolmogorov-Smirnov one-sample test (which makes no assumption about the distribution of the data). *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.
Figure 4
Figure 4. Number of people attacked across 5-day intervals of the lunar cycle.
Solid circles: days when the moon was waxing; double circles: days when waning. Yellow area indicates average hours of daylight. Fewer people were attacked between 6:00 and 9:45 PM on the 5th–14th days of the lunar cycle (when the moon is increasingly bright and always above the horizon in the evening); most victims were attacked on the 15th–29th days (when the moon rises later after sunset each evening).
See this image and copyright information in PMC

References

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