Ctenosaura similis is found throughout Mexico, large areas in Central America, and islands adjacent to Panama (Halliday and Adler 1992).
Biogeographic Regions: nearctic (Native ); neotropical (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Distribution: S Mexico (Yucatan), Nicaragua, Guatemala, El Salvador, Honduras, Belize, Costa Rica, Panama, Old Providence Island (Colombia), San Andres Island USA (introduced to Florida)
Type locality: Restricted to Tela, Honduras (by BAILEY 1928)
The ctenosaurs are large, bulky lizards with adult males reaching up to 18 inches long with a 18-inch tail. They are predominantly black but the dorsal surface may show black bands on a greyish background. Most have black mottling on their backs. The color may also ligthen after basking in the sunlight with yellowish and orange markings becoming evident along the sides. Adult males and females are dimorphic. Adult males have well developed dorsal crests and small dewlaps. The dewlap, the crescent of skin that can be extended under the throat, is not inflated. A small bone bows out to extend the dewlap during times of threat, courtship, or while defending territory. Females lack obvious crests. There is considerable variation with age and sex and therefore identification may be difficult. The lizards have tails ringed with rows of sharp, curved spines, hence the name spiny-tailed iguana. The spines down the back are short. Juveniles tend to be olive-green becoming tan and then finally greyish as they grow (Grzimek 1990; Roberts and Roberts 1993; Cogger and Zweifel 1998).
Range mass: 0 to 0 kg.
Average mass: 1 kg.
Catalog Number: USNM 11003
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Locality: No Further Locality Data, Mexico
Moist Pacific Coast Mangroves Habitat
This taxon occurs in the Moist Pacific Coast mangroves, an ecoregion along the Pacific coast of Costa Rica with a considerable number of embayments that provide shelter from wind and waves, thus favouring mangrove establishment. Tidal fluctuations also directly influence the mangrove ecosystem health in this zone. The Moist Pacific Coast mangroves ecoregion has a mean tidal amplitude of three and one half metres,
Many of the streams and rivers, which help create this mangrove ecoregion, flow down from the Talamanca Mountain Range. Because of the resulting high mountain sediment loading, coral reefs are sparse along the Pacific coastal zone of Central America, and thus reef zones are chiefly found offshore near islands. In this region, coral reefs are associated with the mangroves at the Isla del Caño Biological Reserve, seventeen kilometres from the mainland coast near the Térraba-Sierpe Mangrove Reserve. The Térraba-Sierpe, found at the mouths of the Térraba and Sierpe Rivers, is considered a wetland of international importance.
Because of high moisture availability, the salinity gradient is more moderate than in the more northern ecoregion such as the Southern dry Pacific Coast ecoregion. Resulting mangrove vegetation is mixed with that of marshland species such as Dragonsblood Tree (Pterocarpus officinalis), Campnosperma panamensis, Guinea Bactris (Bactris guineensis), and is adjacent to Yolillo Palm (Raphia taedigera) swamp forest, which provides shelter for White-tailed Deer (Odocoileus virginianus) and Mantled Howler Monkeys (Alouatta palliata). Mangrove tree and shrub taxa include Red Mangrove (Rhizophora mangle), Mangle Caballero (R. harrisonii) R. racemosa (up to 45 metres in canopy height), Black Mangrove (Avicennia germinans) and Mangle Salado (A. bicolor), a mangrove tree restricted to the Pacific coastline of Mesoamerica.
Two endemic birds listed by IUCN as threatened in conservation status are found in the mangroves of this ecoregion, one being the Mangrove Hummingbird (Amazilia boucardi EN), whose favourite flower is the Tea Mangrove (Pelliciera rhizophorae), the sole mangrove plant pollinated by a vertebrate. Another endemic avain species to the ecoregion is the Yellow-billed Cotinga (Carpodectes antoniae EN). Other birds clearly associated with the mangrove habitat include Roseate Spoonbill (Ajaia ajaja), Gray-necked Wood Rail (Aramides cajanea), Rufous-necked Wood Rail (A. axillaris), Mangrove Black-hawk (Buteogallus anthracinus subtilis),Striated Heron (Butorides striata), Muscovy Duck (Cairina moschata), Boat-billed Heron (Cochlearius cochlearius), American White Ibis (Eudocimus albus), Amazon Kingfisher (Chloroceryle amazona), Mangrove Cuckoo (Coccyzus minor), Yellow Warbler (Setophaga petechia), and Black-necked Stilt (Himantopus mexicanus VU) among other avian taxa.
Mammals although not as numerous as birds, include species such as the Lowland Paca (Agouti paca), Mantled Howler Monkey (Alouatta palliata), White-throated Capuchin (Cebus capucinus), Silky Anteater (Cyclopes didactylus), Central American Otter (Lontra longicaudis annectens), White-tailed Deer (Odocoileus virginianus), feeds on leaves within A. bicolor and L. racemosa forests. Two raccoons: Northern Raccoon (Procyon lotor) and Crab-eating Raccoon (P. cancrivorus) can be found, both on the ground and in the canopy consuming crabs and mollusks. The Mexican Collared Anteater (Tamandua mexicana) is also found in the Moist Pacific Coast mangroves.
There are a number of amphibians in the ecoregion, including the anuran taxa: Almirante Robber Frog (Craugastor talamancae); Chiriqui Glass Frog (Cochranella pulverata); Forrer's Grass Frog (Lithobates forreri), who is found along the Pacific versant, and is at the southern limit of its range in this ecoregion. Example salamanders found in the ecoregion are the Colombian Worm Salamander (Oedipina parvipes) and the Gamboa Worm Salamander (Oedipina complex), a lowland organism that is found in the northern end of its range in the ecoregion. Reptiles including the Common Basilisk Lizard (Basiliscus basiliscus), Boa Constrictor (Boa constrictor), American Crocodile (Crocodilus acutus), Spectacled Caiman (Caiman crocodilus), Black Spiny-tailed Iguana (Ctenosaura similis) and Common Green Iguana (Iguana iguana) thrive in this mangrove ecoregion.
- World Wildlife Fund & C. Michael Hogan. 2010. "Moist Pacific Coast mangroves". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed.Mark McGinley. updated 2013
- S.D. Davis, V.H. Heywood, O. Herrera-Mcbryde, J. Villa-Lobos and A.C. Hamilton. 1997. Centres of Plant Diversity: Volume 3 The Americas. Information Press, Oxford, UK. ISBN: 2831701996
Habitat and Ecology
These lizards are great diggers and baskers. They are found around ruins, stone walls, rocky open slopes and branches of large trees along the open borders of the forests. They generally live in dry, arid, open terrain. (Ervin 1992)
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest
The ctenosaur is generally herbivorous, particularly on legume fruits, but is also known to have a diverse carnivorous diet that consist of small animals. Ctenosaurs have eaten rodents, bats, frogs, small birds, and a variety of insects. They have even been noted to eat eggs of their own young, and in one case, the tail of a juvenile was found inside an adult male, suggesting cannibalism. Youngsters are primarily insectivorous, switching into herbivorous habits as adults. (Murphy 1989; Roberts and Roberts 1993)
Life History and Behavior
Status: captivity: 4.8 years.
Lifespan, longevity, and ageing
This species becomes sexually mature at around 3 or 4 years of age. They congregate and mate during specific times of year that varies between populations. Male iguanas possess a pair of intromittent organs, the hemipenes. When not in use the hemipenes lie adjacent to the cloaca within the base of the tail.
During sexual activity one hemipenes is everted by the action of muscles and fills with blood. In copulation, which follows courtship behavior, only a single hemipenis is inserted into the female's cloaca, and the sperm travel along a groove in the hemipenis. Retraction of the hemipenis is accomplished by drainage of the blood sinuses and activation of retractor muscles that invert the structure as it is withdrawn.
In breeding season, the oviparous females then migrate to suitable areas to nest. After digging a burrow about half a meter deep, the female lays 2 to 25 eggs in the nest. She then defends the burrow for some time to prevent other females from nesting in the same spot. The young iguanas hatch 3 to 4 months later and then take about a week to dig their way out of the nest. These tiny iguanas can easily fit in the palm of a hand. If they survive the first difficult years of life, when food is often scarce and predators such as hawks and owls are dangers, these iguanas can live more than 60 years. (Whitfield 1984; Burton 1972; Halliday and Adler 1992)
Molecular Biology and Genetics
Statistics of barcoding coverage: Ctenosaura similis
Public Records: 0
Specimens with Barcodes: 2
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
Man and his domestic animals are inevitably destroying the iguanas' environments and their species. The domestic animals such as cows devour most of the vegetation, which are the food sources for the iguanas. Their flesh is relished in many parts of the world but it is not overly exploited. In parts of South America iguanas are hunted by men imitating the screams of hawks. The iguanas' reaction to the cries is to "freeze" and they are then easily caught (Murphy 1989).
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
This species has been reported as common in its habitat in Belize and Costa Rica (Stafford and Meyer 2000, Savage 2002). In Honduras, some subpopulations of this species are severely depleted (Puerto Lempira, Gracias a Dios), whereas it remains abundant along the entire Pacific versant in Valle and Choluteca (J. McCranie pers. comm. 2009).
Harvesting for human consumption does occur, but this does not seem to be having a negative affect on the population size of this species. The iguana is locally captured and eaten and is sold in markets throughout Mexico and Central America, where it is believed to have medicinal value (Savage 2002).
This species is found in several protected areas across its range. Further monitoring of this species is needed, especially to determine if harvest levels are increasing.
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
No documented example
Economic Importance for Humans: Positive
The spiny-tailed iguana is edible and is a popular food for much of the rural population of Central America. In some areas, eating their flesh is considered potent "medicine", with the person deriving the iguana's strength after eating it. Also, the spiny-tailed iguanas are supposed to be a cure for impotence (Kaplan 2000).
Ctenosaura similis, commonly known as the black spiny-tailed iguana, black iguana, or black Ctenosaur, is a lizard native to Mexico and Central America that has been introduced to the United States in the state of Florida. It is the largest species in the genus Ctenosaura and has been recorded as the fastest running lizard on earth.
The black spiny-tailed iguana was first described by British zoologist John Edward Gray in 1831. The generic name, Ctenosaura, is derived from two Greek words: ctenos (Κτενός), meaning "comb" (referring to the comblike spines on the lizard's back and tail), and saura (σαύρα), meaning "lizard". Its specific name is the Latin word similis meaning "similar to", a common description found in Linnean taxonomy when referring to a new taxon.
Black spiny-tailed iguana have distinctive keeled scales on their long tails, which gives them their common name. They are the largest members of the genus Ctenosaura, males capable of growing up to 1.5 meters (4 ft 11 in) in length and females slightly shorter at 1 meter (3 ft 3 in). They have a crest of long spines which extends down the center of the back. Although coloration varies extremely among individuals of the same population, adults usually have a whitish gray or tan ground color with a series of 4–12 well-defined dark dorsal bands that extend nearly to the ventral scales. Males also develop an orange color around the head and throat during breeding season with highlights of blue and peach on their jowls.
Diet and behavior 
Black spiny-tailed iguanas are excellent climbers, and prefer a rocky habitat with plenty of crevices to hide in, rocks to bask on, and nearby trees to climb. They are diurnal and fast moving, employing their speed to escape predators but will lash with their tails and bite if cornered. The Guinness Book of World Records lists the running speed of this species at 21.7 mph or 34.9 km/h making it the world's fastest lizard.
They are primarily herbivorous, eating flowers, leaves, stems, and fruit, but they will opportunistically eat smaller animals, eggs, and arthropods. Juveniles tend to be insectivores becoming more herbivorous as they get older.
The black spiny-tailed iguana is native to Central America, and has the widest range of all Ctenosaura species from the Isthmus of Tehuantepec to northeastern Nicaragua and western Panama on the respective Atlantic and Pacific coasts. It is commonly found throughout Costa Rica, Honduras and has been reported in Colombia. In addition to its varied appearance it may interbreed with other Ctenosaur species throughout this range.
The black spiny-tailed iguana has been introduced to South Florida and reproduces in the wild in several feral populations. On the south-eastern Florida coast, black spiny-tailed iguanas have been found on Key Biscayne, Hialeah, and in Broward County. On the south-western Florida coast, it has been discovered on Gasparilla Island and in adjacent areas, throughout Lee and Charlotte counties. This iguana has also been introduced to several islands in the Caribbean. As this species will opportunistically feed on small vertebrates, such as fish, rodents, eggs, birds, and even hatchling sea turtles it may pose a threat to endangered native species.
Mating generally occurs in the spring. Males show dominance and interest by head bobbing; eventually the male will chase the female until he can catch her and subdue her. Within eight to ten weeks, the female will dig a nest and lay clutches of up to 30 eggs. The eggs hatch in 90 days with the hatchlings digging their way out of the sand. These juveniles are typically green with brown markings, although all brown hatchlings have been recorded as well.
Commercial usage 
In some parts of Central America, the black spiny-tailed iguana is farmed alongside the green iguana as a food source and for export for the pet trade;  see iguana meat. Although it is heavily hunted it does not appear to be endangered in any of its native territory.
- The Reptile Database. www.reptile-database.org.
- "Ctenosaura similis". Integrated Taxonomic Information System. Retrieved 30 December 2007.
- Malfatti, Mark (2007). "A Look at the Genus Ctenosaura: Meet the World's fastest lizard and its kin". Reptiles Magazine 15 (11): 64–73.
- Hollingsworth, Bradford D. (2004). "The Evolution of Iguanas an Overview and a Checklist of Species". Iguanas: Biology and Conservation (University of California Press): 34–35. ISBN 978-0-520-23854-1
- Köhler, Gunther (1996). "Notes on the systematic status of the taxa acanthura, pectinata, and similis of the genus Ctenosaura". Senckenbergiana Biologica 30 (1): 33–43
- Garland, T., Jr. (1984). "Physiological correlates of locomotory performance in a lizard: an allometric approach". American Journal of Physiology 247 (5 Pt 2): R806–R815. PMID 6238543.
- Krysko, K. L. & King, F. W. & Enge, K. M. & Reppas, A. T. (2003): Distribution of the introduced black spiny-tailed iguana (Ctenosaura similis) on the southwestern coast of Florida.- Florida Scientist, Lawrence, Kansas; 66 (2): 74-79.
- Sanchez, Alejandro (2007-12-31). "Father Sanchez's Web Site of West Indian Natural History Diapsids I: Introduction; Lizards".