Ctenosaura hemilopha, also known as the Cape spiny-tailed iguana or Baja California spiny-tailed iguana, is a species of spinytail iguana endemic to Baja California. It is arboreal and primarily herbivorous, although it can be an opportunistic carnivore. Males may grow up to 100 centimeters (39 in) in length, while females are smaller, with a length of up to 70 centimeters (28 in). Five subspecies are currently recognized.

The existence of mainland and insular populations of this species has been valuable in providing biologists with study and control groups comparing the evolution of island populations and their mainland counterparts. The San Esteban Island subspecies (C.h. conspicuosa) coexists with the giant San Esteban chuckwalla, contrary to predictions of ecological niche theory.

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