The reproductive cycle of the western whiptail lizard (Cnemidophorus tigris) in Southern Arizona

Reproduction in Cnemidophorus tigris at Tucson, Arizona follows a seasonal cycle in which gonadal size is minimal in September‐October. Male reproductive organs gradually recrudesce during the winter months spent underground. After the lizards emerge from hibernation in March‐April the testis, seminiferous epithelial height and tubule diameter gradually increase in size through April and May, reaching maximum size in June‐July followed by rapid regression in August. Mating is first observed in the field in May. The ovaries undergo a period of heavy yolk deposition from early April to May, and remain functional until August. A thick circumtesticular subtunic layer of equivalent interstitial material (Leydig cells) is reported and described for the testis of Cnemidophorus.