To be more precize, it's the Mexican spiny-tailed iguana Ctenosaura pectinata which is doing quite well after being introduced to Texas, Arizona and Florida.
In it's native Mexican distribution it's not doing so well and even listed on the Mexican Red List as being threatened..... !
Actually, the lizards on the museum grounds are hybrids between San Esteban and Sonoran Spiny-tailed Lizards. They are reproducing on grounds but since their release in the 1970's have not expanded their range beyond the property.
