Females are smaller, averaging about 13 inches in total length. Both subspecies of C. calyptratus survive in the climatically diverse area of the western coast of Yemen and the southwestern coast of Saudi Arabia. Yemen has a low coastal plain bordered by the Red Sea. This plain rises sharply into mountain peaks with can reach altitudes of 12,000 feet. This extreme topography creates different climates.
Moisture evaporating from the Red Sea is trapped by the mountains.
As a result, the low plains along the coast are not only hot, but humid as well. As the moisture moves up into the mountains, it forms clouds which rain down on the western slopes. Some areas here receive large amounts of rainfall. In Ibb, a town north of Ta'izz, the mountains receive as much as 80 inches of rain annually. This rainfall supports lush vegetation and an abundant insect population.