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. Much of this rainfall does not reach the higher mountain regions, so the plateaus are much dryer. To the north, in Saudi Arabia, where the mountains are absent, the climate is quite arid. This ability of C. calyptratus to survive this very diverse habitat is probably what has lead to it surviving so successfully in captivity.