The genus Ctenosaura is presented. Twelve species have been recognised so far. Except for C. bakeri they all inhabit hot, arid environments in Central America. The animals are in general herbivorous. The four largest species (C. acanthura, C. hemilopha, C. pectinata and C. similis) grow to a length of 120 cm and live in the most northern parts of the region. They prefer open areas with numerous structural elements. Young animals are almost exclusively terrestrial while adults frequently climb trees either when fleeing from danger or to bask in the sun. Ctenosaurs have a small home range and demonstrate a pronounced territorial behaviour. The animals become sexually mature between the ages of 16-30 months. Courtship takes place at the beginning of the dry season. The eggs are laid six to eight weeks later in a nest dug in the ground. Incubation takes a little less than three months. The hatchlings appear at the beginning of the rainy season. C. oedirhina lives on the Honduran island of Roatan. C. bakeri is endemic to the neighbouring island of Utila where it inhabits high trees in mangrove swamps. During April and May the females travel to sandy beaches to lay their eggs. C. palearis, the species with the most pronounced dewlap, is found in three localities in Guatemala and Honduras. C. quinquecarinata, identified by the five keels of spiny scales on the tail, is a rather small Ctenosaur and is found in dispersed areas in Mexico, El Salvador, Nicaragua and Costa Rica. C. flavidorsalis, was recently discovered near La Paz, Honduras. It has a yellow coloured back and a completely spined tail. C. clarki is a small, very robust animal from Michoacan, Mexico. C. alfredschmidti, the most recently described Ctenosaur from Campeche, Mexico, has a bad reputation among the local people; it is thought to be venomous. C. defensor is a small, beautifully coloured species with a heavily armoured tail from Yucatan, Mexico. Observations on free living animals are used to form the basis of recommendations on the housing and care of Ctenosaurs in captivity. Finally a key to the species is provided.