Ctenosaura palearis


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Ctenosaura palearis
Species Authority: Stejneger, 1899
Common Name/s:
English Motagua Spiny-tailed Iguana, Guatemalan Black Iguana, Guatemalan Spiny-tailed Iguana
Spanish Garrobo del Motagua, Iguana de Órgano, Iguana de Tuno
Enyaliosaurus palearis (Stejneger, 1899)

Assessment Information [top]

Red List Category & Criteria: Endangered A4acd; B1ab(i,ii,iii,iv,v); C2a(i) ver 3.1
Year Published: 2011
Date Assessed: 2011-03-03
Assessor/s: Ariano-Sánchez, D. & Pasachnik, S.
Reviewer/s: Grant, T. & Hoffmann, M.
Contributor/s: Cotí, P., Montgomery, C.E. & Burgess, J.
The Motagua Spiny-tailed Iguana has an extent of occurrence less than 930 km² and the area of occupancy was estimated to be 598 km² in 2008 and was expected to continue declining. The population is severely fragmented and is threatened by habitat loss and local extirpation of certain subpopulations due to excessive hunting and trade.  The total population size is not known, but it is thought there may be fewer than 2,000 mature individuals with the largest subpopulation numbering about 150 mature iguanas. There is a continuing decline due to hunting and trade, and habitat quality is also decreasing due to agriculture and the increased mortality of cacti (their main food and shelter source). Local people interviewed describe a dramatic decrease in the wild iguana population over the last 20 years.

This is a non-genuine change from the most recent assessment due to misinterpretation of the Red List Criteria.
2004 Critically Endangered

Geographic Range [top]

Range Description: The Motagua Spiny-tailed Iguana is restricted to upper Rio Motagua valley in eastern Guatemala and has an estimated extent of occurrence of 930 km². Occurs at elevations ranging from 200 to 900 m above sea level.
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The total population size of Motagua Spiny-tailed Iguanas is not known, but perhaps is less than 2,000 mature individuals. The population is fragmented into 25 subpopulations, the largest of which occurs near Cabañas, Zacapa, and is thought to have approximately 140 mature individuals. Local extinctions have occurred in some areas, such as Morazan in the El Progreso department (Cotí and Ariano 2008).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: The Motagua Spiny-tailed Iguana occurs in areas of dry forest and thorn scrub. The predominant plant species in areas where iguanas are present are tree cacti, including Pitayo Organ Pipe Cactus (Stenocereus pruinosus) and Old Man Cactus (Pilosocereus leucocephalus), and tree species such as the Yellow Plum (Ximena americana), Yellow Bells (Tecoma stans) and Licania hypoleuca. Areas without iguanas are dominated by the trees Cacho de Toro (Bucida macrostachya), Black Cabbage-bark (Lonchocarpus rugosus, Guava (Psidium sp.) and Stenmadenia obovata. The shelters used by this species are hollow trunks or branches of the cactus and trees listed above. Iguanas are usually found within the shelters using their spiny tails to block the entrance. This iguana is one of the main species that feeds on the fruit of the Pitayo Organ Pipe Cactus in the dry forest of Motagua Valley. The seeds of this cactus have been found in faeces and also attached to the external gular parts of the iguanas (Cotí and Ariano 2008). In this way, the Motagua Spiny-tailed Iguana is a disperser of this cactus species and thus can contribute to forest cover regeneration.

The eggs of the Motagua Spiny-tailed Iguana are one of the main food sources for the Motagua Valley Beaded Lizard (Heloderma horridum charlesbogerti) (Ariano-Sánchez 2007). Though not formally listed, this beaded lizard subspecies is thought to be highly threatened and in extreme danger of extinction (Ariano-Sánchez 2006, Ariano-Sánchez and Salazar 2007). Therefore, maintaining a stable population of the iguana may be relevant to conserving the wild populations of the beaded lizard. The Motagua Spiny-tailed Iguana is a keystone species for the dry forests of the Motagua Valley because its presence is considered crucial to maintaining the organization of the ecological community by its position in the food chain and its important role as a seed disperser (Cotí and Ariano 2008).

The maximum size including tail for this iguana is 57 cm (a male), and the average size (including tail) for each sex is 36.40 ± 4.45 cm for females and 46.31 ± 9.0 cm for males (Cotí 2008). The maximum longevity recorded for this iguana is 10.2 years in captivity, with the first reproduction at two years old (De Magalhäes and Costa 2009). The generation length is estimated to be six years. According to local hunters, this species lays between 6 and 12 eggs each year and the incubation period is three months (Cotí 2008).
Systems: Terrestrial

Threats [top]

Major Threat(s): The main threat to the Motagua Spiny-tailed Iguana is habitat loss, which is due primarily to the increase of watermelon crops and the construction of new residential zones within the Motagua Valley.  In some areas cattle farming has triggered land conversion. Open-cast mining projects have also destroyed core habitat. Local people interviewed describe a dramatic decrease in the wild iguana population over the last 20 years. Field observations since 2002 have also shown an increase in mortality of the Pitayo Organ Pipe Cactus due to local changes in rainfall patterns; this cactus represents the main food source and shelter for the Motagua Spiny-tailed Iguana. Feral dogs and cats exist within the range of this iguana, however, evidence of high rates of mortality due to predation has not yet been documented.

It is known that illegal trade and over-harvesting of the Motagua Spiny-tailed Iguana is occurring. People who catch iguanas for meat usually catch six individuals per month, while illegal traders usually catch 50 to 60 individuals per month. Internet and local market surveys have shown that this species is sold in Greece, Germany, and the United States at an average price of US$90  per individual. All sales of this iguana outside of Guatemala are illegal as governmental authorities in Guatemala have not issued exportation permits for this iguana to date. This illegal trade is thought to be the main cause of local extirpation of iguanas in some localities (Cotí and Ariano 2008).

The Motagua Spiny-tailed Iguana is used as a protein source by local villagers. In some areas this iguana is heavily hunted in the breeding season for their eggs, which has a large negative effect on the survival and viability of wild populations (Cotí and Ariano 2008). Hunters catch gravid females to consume in total or they make an incision in the ventral part to extract the eggs, then they are sewn up and released. Predictably, these animals soon succumb to bacterial infections and internal haemorrhages.

Conservation Actions [top]

Conservation Actions: Zootropic, International Reptile Conservation Foundation, and Zoo Atlanta have initiated a conservation project for the Motagua Spiny-tailed Iguana. The project includes environmental education for local villagers and children focusing on the importance of conserving this iguana and the development of a defined hunting season. The project involves a semi-captive breeding programme on a private reserve owned by Zootropic and is within the distribution area of the iguana. Within this reserve there is also a scientific research station operated by Zootropic and its partners for monitoring the wild population and its habitat. The reserve encompasses 132 hectares, and is the only area in which this iguana is afforded complete protection from hunting and habitat destruction. An additional 1,421 hectares of suitable iguana habitat iguana exists within ten areas where habitat destruction is prohibited. Though this additional land is technically protected, there is little to no enforcement, thus iguanas have been extirpated in some of these areas. Some local villagers are currently developing a sustainable-use plan for this iguana.

In an effort to reduce illegal trade and over-harvesting, the Motagua Spiny-tailed Iguana was recently listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Citation: Ariano-Sánchez, D. & Pasachnik, S. 2011. Ctenosaura palearis. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <>. Downloaded on 20 April 2014.
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