Not venomous · Native to Mexico · Introduced in Florida

Mexican spiny-tailed iguana

Ctenosaura pectinata (Wiegmann, 1834)

Also called Mexican black iguana, garrobo
Data updated October 2026

Dark Mexican spiny-tailed iguana with white blotches on the shoulder and pale crest spines, standing on sand
Fig. 1 — Adult with a dark body, pale shoulder blotches and a crest of pale spines.
Mexican spiny-tailed iguana lying along a branch among palm fronds
Fig. 2 — Resting along a branch among palms. The banded tail is ringed with spines.

At a glance

A large, dark iguana found only in Mexico, mainly along the Pacific side from Sonora to Chiapas. It eats mostly plants but also takes insects and other small animals. It is protected in Mexico and has been introduced to Florida.

01

Identification

Adults are dark gray to black, often with pale blotches or bands on the body, and a crest of spines along the back. The tail is ringed with sharp, pointed scales. In Florida it looks almost the same as the black spiny-tailed iguana, and even scientists can find the two hard to tell apart.

  1. 01Spiny tail rings. Whorls of sharp scales circle the tail.
  2. 02Dark body. Mostly black or dark gray, often with pale markings on the shoulders and sides.
  3. 03No round cheek scale. Like other spiny-tailed iguanas, it lacks the big round jaw scale of the green iguana.

Commonly confused with

02

Size

01 ft2 ft3 ft4 ft Adult · about 3 ft (91 cm)

Spiny-tailed iguanas in Florida are reported at about 2 to 4 feet (61–122 cm) as adults. In a study population in central Mexico, adult females measured about 9½ to 13½ inches (24–34 cm) from snout to vent, not counting the tail.

03

Range & habitat

Mexican spiny-tailed iguana on a mossy rock wall in shade
Fig. 3 — Rock walls and crevices give spiny-tailed iguanas places to bask and hide.

The Mexican spiny-tailed iguana is found naturally only in Mexico. It ranges along the Pacific coast from southern Sonora to Chiapas, including offshore islands such as the Marías Islands and Isla Isabel, and inland into parts of Puebla, Morelos and the State of Mexico. It lives in dry deciduous forest and thorn scrub.

Introduced populations exist in Florida, where spiny-tailed iguanas are seen in rocky areas, along canals and in towns.

State guide: Florida

04

Diet & predators

This iguana is mainly a plant eater, but it is omnivorous. One study found that plants made up about 70 percent of its food, with the rest made up of insects, crustaceans and smaller amounts of millipedes and snails. Cannibalism has also been recorded on Isla Isabel.

Feeds on

  • Leaves, flowers and fruit
  • Insects
  • Crustaceans
  • Millipedes and snails
Fresh collard green leaves
Food — mainly plants.
House cricket
Food — insects.

05

Behavior & seasons

Mexican spiny-tailed iguanas are active by day. In a study in central Mexico they foraged by sitting and waiting rather than searching widely. There, the dry season lasts about eight months, from October to May.

06

Reproduction

Females lay one clutch a year. In central Mexico eggs were laid in April, and clutches averaged about 31 eggs, ranging from 12 to 52. Other reports give typical clutches of 30 to 50 eggs, and an incubation time of about 90 days.

07

Conservation

In Mexico the species is listed as threatened under the national endangered species standard (NOM-059-SEMARNAT-2010). Its meat and eggs are eaten locally and sold in markets. In Florida, spiny-tailed iguanas are non-native and tend to eat more animal food than green iguanas, so they pose a greater direct threat to native wildlife.

Keep reading

Sources

Data updated October 2026 · How we build these pages