Hayes, F. E., W. K. Hayes, K. R. Beaman, and L. E. Harris, Jr. 1992. Sleep-like behaviour in the
Gal�pagos Tortoise (Geochelone elephantopus). Herpetological Journal 2:51-53.
Abstract.--Sleep-like behaviour of Gal�pagos Tortoises (Geochelone elephantopus) was studied at Volc�n Alcedo, Isabela Island, Gal�pagos Islands, Ecuador. At midday, most tortoises found asleep were in the open with head and limbs extended; during cooler evening hours, sleeping tortoises usually occupied forms with head and limbs withdrawn. Variability in sleep-like postures during different periods of inactivity probably reflects alternative thermoregulatory strategies. Forms occupied by inactive tortoises (n = 53) comprised vegetation (51%), soil (30%) and other toritoises (19%). The absence of native predators on Gal�pagos implies a thermoregulatory rather than antipredator function for form use. |
