Terezow et al.—Emergence and movement of tuatara

New Zealand Journal of Zoology abstracts

Circadian emergence and movement of captive juvenile tuatara (Sphenodon spp.)

Marianna G. Terezow^*

Nicola J. Nelson

Timothy J. Markwell

School of Biological Sciences
Victoria University of Wellington
PO Box 600
Wellington 6140, New Zealand

nicola.nelson@vuw.ac.nz

tim.markwell@vuw.ac.nz

^*Corresponding author and present address: GNS Science Ltd, 1 Fairway Drive, Avalon, PO Box 30368, Lower Hutt 5040, New Zealand.
m.terezow@gns.cri.nz

Abstract Knowledge of the circadian behaviour of young tuatara (Sphenodon spp.) is relatively scarce because tuatara are difficult to observe in the wild. We document diurnal, nocturnal and crepuscular emergence and movements (half-body movement, walking and running) of three groups of captive juvenile tuatara (2- and 3-year-old Sphenodon guntheri, and 5-year-old S. punctatus). Juvenile tuatara emerge predominantly at night, but move around above ground, mainly during the day and around sunset. Differences in emergence and movement scores between the three study groups were evident, probably linked with age, species or housing conditions, which were inevitably coupled in our study. We found that 2-year-old tuatara in captive conditions emerged less frequently than, but once above ground, moved more than 3- and 5-year-olds in semi-captive conditions. Activities in semi-captive conditions were not correlated with temperature, light or humidity. We conclude that young tuatara may be primarily adapted to nocturnal activity, but thermal restrictions and possible hardwired adaptations to avoid predators and conspecifics may make day-time movements safer.

Keywords captivity; circadian rhythms; emergence; movement; Sphenodon; tuatara

Z07055; Online publication date 27 June 2008; Received 15 November 2007; accepted 6 April 2008

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