Most animals show strong 24-h patterns of activity, usually being diurnal or nocturnal.
An Australian desert skink, Ctenotus pantherinus, is unusual in being active day and
night when all other Ctenotus species are diurnal, making it an excellent model to
explore factors that promote night-time activity. We tested whether C. pantherinus
1) selects cooler temperatures than diurnal skinks, 2) shows no difference in mean
selected temperature between day and night, 3) has the same metabolic rate during
the day and night, 4) selects termites over other prey types, 5) can detect prey using
only auditory or olfactory senses, and 6) experiences lower predation risk at night
than during the day. C.pantherinus shows many features of diurnal skink species, with
a high mean selected temperature (36.1+/-1.6 degrees C) that is the same night and
day, and a 32% lower metabolic rate at night than during the day. C.pantherinus selects
termite prey over other insects and can detect prey using only auditory and olfactory
senses; models of C. pantherinus experienced less predation at night than during the
day. Preference for termites and reduced predation risk at night favour opportunistic
nocturnal activity in this predominantly diurnal lizard and may contribute to its
wide geographic distribution in arid Australia.