Influence of Season and Moonlight on Temporal-Activity Patterns of Indian Crested Porcupines (Hystrix indica)

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Abstract
During a 1-year period, onset and termination of nocturnal surface activity were monitored in as many as eight free-ranging Indian crested porcupines (Hystrix indica) in the Negev desert highlands of southern Israel by radio-location telemetry. Porcupines optimized winter (October–March) activity for minimal exposure to moonlight, but moonlight avoidance waned thereafter and disappeared by late summer (August–September). Rain curtailed activity, but there was no correlation between duration of activity and minimum near-ground temperatures. Individual variation in activity was large in all seasons. Duration of activity and the proportions of dark and nights hours used increased from winter to late summer. Adult-sized animals (14.1 ± 3.0 kg body mass) averaged 7.0 ± 0.4 h surface activity year-round, but this peaked at 9.2 ± 1.3 h in late summer when nearly all night hours were used. In winter, activity averaged 6.7 ± 0.8 h and porcupines were active for longer periods on dark nights than on moonlit nights. Seasonal changes in duration of activity (and moonlight exposure) may have been caused by variations in available dark hours relative to surface-activity requirements or to food-density fluctuations, but they did not clearly correspond to key stages of porcupine reproduction.