The critically endangered Mona Island iguana, Cyclura stejnegeri, is threatened by nest predation by feral pigs, invasive plants that reduce nesting area, and high juvenile mortality. Even though studies in the last 45 years have been sporadic, they had led to different management actions such as protecting nesting areas from feral pig incursion and expanding suitable nesting sites by eradicating the Australian pine (Casuarina equisetifolia) and other invasive plant species. In addition, from 1999 to 2016 a head-start program (HST) was implemented, to increase the recruitment and survival of juvenile iguanas. In 2021, we conducted a 10-week mark-recapture study to survey the population. Data obtained suggest that the Mona iguana lifespans can exceed 32 years, iguanas are very philopatric staying in the same areas over many years, and that health parameters for HST individuals are similar to those of wild ones. These findings provide new information that should be considered when implementing management actions directed at guaranteeing the survival of the Mona iguana.