For example, I obtained two captive born Uromastyx aegypticus that were three inches long. Within eight months one animal was five inches long and the other 11 inches and much bulkier. The only difference in husbandry was that the larger animal would eat insects and smaller one would not. I have also observed slow growth in captive born Uromastyx acanthinurus . However reproduction is not a regular occurrence.
All breeders provide a winter cool down to stimulate reproduction.
Apparently Uromastyx take several years to reach sexual maturity. As a comparison, North American chuckawallas, an ecological equivalent, take five to seven years to reach sexual maturity. Some of the smaller Uromastyx may reach sexual maturity in two or three years. The Egyptian spiny-tailed lizard at the Indianapolis Zoo. Thatcher, Terry. 1990.