Five-keeled spiny-tailed iguana  (Ctenosaura quinquecarinata)

Classified as Endangered (EN) on the IUCN Red List (1).

The five-keeled spiny-tailed iguana (Ctenosaura quinquecarinata) is a medium-sized, robust lizard so named for the five rows of enlarged spines on its flattened, heavily armoured tail (2). The adult five-keeled spiny-tailed iguana’s tail is almost twice the length of its body (3).

Excellently camouflaged in its forest habitat, the five-keeled spiny-tailed iguana is usually dull olive-green, with darker cross bands and light green blotches across the back and limbs (3) (4). Most of the underparts are greyish-white, except for a black area around the throat. Males have a conspicuous large black dewlap (3).

Newborn five-keeled spiny-tailed iguanas are greyish-brown with dark bands (3), but after a few months they become bright green, before developing the darker adult colouration at around six months. (2) (3).

Rarely seen, the five-keeled spiny-tailed iguana is only found in an area of about 5,000 square kilometres along the Pacific region of Nicaragua and along the north-western region of Costa Rica, including several small islands (1) (2) (3).

The global population of the five-keeled spiny-tailed iguana is separated into around 10 to 15 sub-populations (1).

The five-keeled spiny-tailed iguana tends to favour hot, dry areas, in tropical dry forests and relatively open woodland. They are semi-arboreal and are often found on tree stumps or in tree hollows and under rocks where they seek refuge from predators (1) (2) (3).

There is little information available on the behaviour, reproduction and social systems of the five-keeled spiny-tailed iguana. However, many aspects of its life history can be assumed to be similar to other iguana species. Like all other iguanas, the five-keeled spiny-tailed iguana is active during the day (5).

Similar to other members of the Ctenosaura genus, the five-keeled spiny-tailed iguana is oviviparous. Little is known about the number of eggs laid in the wild, although a captive bred female is known to have laid five eggs in one clutch (2).

Unlike the adults, the young five-keeled spiny-tailed iguana relies heavily on animal protein, mainly from insects, and become increasingly herbivorous as they mature. Adults are mostly herbivorous, but small mammals, birds, other lizards and eggs make up a small part of their diet (3).

The population of five-keeled spiny-tailed iguanas could decline by as much as 30 percent if current rates of habitat loss are maintained. In 2005, it was estimated that were fewer than 2,500 individuals remaining in the wild (1).

Habitat loss and degradation are the primary threats to the five-keeled spiny-tailed iguana. Many traditional small holdings are changing into larger industrial farms, which can lead to reduced tree cover, vegetation and habitat diversity (6). Moreover, many cattle ranchers and farmers set fire to their land twice a year, which reduces habitat and refuge sites for the iguanas. In addition, most farmers in Nicaragua use fire wood obtained from the iguanas’ habitat for cooking, which again reduces potential refuge sites (4).

Another threat to the five-keeled spiny-tailed iguana population is unregulated exploitation for the pet trade. They are not currently listed under the Convention on International Trade of Endangered Species (CITES), meaning that trade in this species is not regulated (7).

Five-keeled spiny-tailed iguanas currently have no legal protection (1). The Lost Canyon Nature reserve does, however, offer a refuge for this species. The Lost Canyon Nature Reserve in Nicaragua has made five-keeled spiny-tailed iguanas their flagship species.

Since 2009, the Lost Canyon Nature Reserve have been working on the Nicaraguan Iguana Project (NIP).  As part of this scheme, five-keeled spiny-tailed iguanas found outside the reserve are relocated to the NIP area within the reserve, which contains abundant natural habitat. This ensures immediate survival for the iguanas and facilitates mating (4). Protection within Lost Canyon Nature Reserve also allows herpetologists to carry out much needed study on this species, as recommended by the IUCN (1).

To ensure the five-keeled spiny-tailed iguana population does not decline further, surveys need to be carried out to determine the current population size, as well as managing and monitoring of wild populations (1).

Learn more about the five-keeled spiny-tailed iguana:

• Lost Canyon Nature Reserve:
  http://www.lost-canyon.org