 Mating occurs from May through June . Copulation is preceded by numerous head @-@ bobs on the part of the male , who then circles around behind the female and grasps the nape of her neck . He then attempts to restrain the female in order to maneuver his tail under hers to position himself for intromission . Copulation generally lasts from 30 to 90 seconds , and a pair is rarely observed mating more than once or twice a day . A clutch of anywhere from 1 to 21 eggs are usually laid in June or July depending on the size and age of the female , in nests excavated in pockets of earth exposed to the sun . Several exploratory nests are begun before one is completed . These burrows can range from 16 inches ( 0 @.@ 41 m ) to over 60 inches ( 1 @.@ 5 m ) in length , with an enlarged chamber at its terminal portion to allow the female to turn around . The temperature within nests that have been monitored by researchers remained a constant 32 ° C ( 90 ° F ) throughout the incubation period which ranges from 65 – 90 days . The blue iguana 's eggs are among the largest laid by any lizard . 
