Animal color patterns often have functions in thermoregulation, predation avoidance, and intraspecific communication. Examining intraspecific variation of color patterns is an effective approach to clarify their functions in a specific animal. We investigated the variation of dorsal color pattern within a dry forest population of the Madagascan iguanian lizard, Oplurus cuvieri cuvieri. Mark-and-recapture study showed that the number of dorsal black bands (DBBs) varies from one to seven, and often increases and decreases ontogenetically. Among four factors (snout-vent length, sex, age, and habitat) and three interactions between them, only sex and habitat had significant effects on the number of DBBs. Female lizards and lizards inhabiting a forested area tended to have more DBBs than males and those in an open habitat, respectively. All captive born hatchlings had seven DBBs, and juveniles reared under a 40W lamp retained more DBBs than those reared under a 60W lamp. This suggests that the number of DBBs of O. c. cuvieri is affected by thermal conditions, implying a thermoregulatory function of this color pattern.