Black Spiny-tailed Iguana

Scientific Name
Ctenosaura similis
Also Known As
Black Iguana, Common Spiny-tailed Iguana
Range
Central and Southern Florida
Diet
Flowers, Leaves, Stems, and Fruit
Life Expectancy
19 Years
The Black Spiny-tailed Iguana

Photo 200032739 (c) Carlos G Velazco-Macias, CC BY-NC

Black Spiny-tailed Iguana conservation status - Invasive

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Black Spiny-tailed Iguanas in Central Florida

The black spiny-tailed iguana (Ctenosaura similis) is an invasive lizard that has established breeding populations in Central Florida. Often confused with the native green iguana (Iguana iguana), the black spiny-tailed iguana can be identified by its distinctive spikes, scales, coloration and habits.

This comprehensive guide provides detailed identification tips, biology facts, and prevention and control methods for black spiny-tailed iguanas in Central Florida. Read on to learn about black spiny-tailed iguana characteristics, reproduction, diet, impacts, signs of infestation, and professional removal options if you see these exotic lizards on your property.

Appearance and Identification

Black spiny-tailed iguanas can be distinguished from the similar-looking green iguana, especially at juvenile and adult stages

Adult Black Spiny-tailed Iguana

Photo 106911977 (c) Ty Smith, CC BY-NC

Adult Black Spiny-tailed Iguanas

  • Size: Adults reach up to 54 inches (137 cm) in total length, with the tail making up two-thirds of that length. They weigh around 9 to 17 lbs (4 to 8 kg).
  • Spikes: Large, keratin spikes extend along the back, tail, and sides. These become pronounced in mature iguanas.
  • Coloration: Adults lose the green and dark bands, becoming solid gray or black dorsal color with off-white on the underside. The throat may show orange coloration.
  • Head: Powerful bite strength with teeth adapted to an herbivorous diet. Eyes have golden irises with black pupils.
Juvenile Black Spiny-tailed Iguana

Photo 167598282 © panchoromo, CC BY-NC

Juvenile Black Spiny-tailed Iguanas

  • Size: Hatchlings are 4.5 to 6 inches (11 to 15 cm) long from snout to vent. The tail is equal to or longer than the body.
  • Scales: White spike-like dorsal scales form five rows down the spine and tail. These spikes are soft and flexible in young lizards.
  • Coloration: Juveniles are bright green with bold dark bands running across the body and tail. The underside is pale yellow or white.
  • Head: Triangular head with spiky scales around the neck that can be extended into a crown-like fringe for defense.

The green iguana lacks the distinctive spikes of the black spiny-tailed variety. The squat, heavy-bodied green iguana also has more orange coloration on the sides and underparts.

Maturation Rate

Young black spiny-tailed iguanas grow rapidly after hatching. They begin developing adult coloration around 8 months old as the spikes harden. At 1 to 1.5 years old, they reach sexual maturity and adult size. Rapid growth allows black spiny-tailed iguanas to reproduce early, fueling proliferation in warm Southern habitats.