Lesser Antillean Iguana

Physical Characteristics

The Lesser Antillean Iguana is a rare, medium-to-large arboreal lizard endemic to a few islands in the Lesser Antilles. Known for its elegant proportions, uniform coloration, and lack of certain prominent scale features, it is genetically and physically distinct from the more common Green Iguana (Iguana iguana).

Coloration:

• Adults are typically gray to pale green, often with a subtle bluish or lavender wash over the face, jowls, and limbs.

• Males develop pale pink cheeks and creamy white dewlaps during breeding season.

• Unlike the Green Iguana, they lack bold patterns or orange coloration.

• Juveniles are usually bright green with faint striping, which fades with age.

Head and Eyes:

• The head is narrow and more elongated than that of I. iguana, with a smooth profile and no subtympanic shield(the large circular cheek scale present in Green Iguanas).

• The snout is slender and tapered, with small, rounded eyes positioned laterally.

Dewlap:

• Present but smaller and less pronounced than in the Green Iguana.

• The dewlap is often light-colored or white, and used primarily in thermoregulation and signaling.

Body and Scales:

• The body is slim and graceful, covered in fine, smooth scales.

• A low crest of dorsal spines runs from the neck to the tail, shorter and more uniform than in I. iguana.

• The overall build is more delicate, fitting the species name delicatissima.

Tail:

• The tail is long, slender, and slightly compressed, accounting for more than half the total body length.

• It is used for balance in trees, and may be dropped (autotomized) if attacked.

Limbs and Toes:

• Limbs are long and well-muscled, with sharp claws and elongated toes adapted for climbing.

• The feet are broad and agile, supporting life in tree canopies.

Size:

• Total Length: 3.5 to 5 ft (1.1 to 1.5 m), including tail

• Snout-to-vent length (SVL): 12 to 20 in (30 to 50 cm)

Weight:

• Adults weigh 2.5 to 5 kg (5.5 to 11 lbs), with males slightly larger than females

The Lesser Antillean Iguana’s graceful frame, muted pastel colors, and arboreal build make it one of the most elegant and endangered iguanas in the Caribbean.

Reproduction

The Lesser Antillean Iguana exhibits a seasonal and solitary breeding cycle, closely timed with local rainfall patternsand resource availability on its native islands. Its reproductive strategy includes slow maturation, low clutch frequency, and high hatchling vulnerability, all of which contribute to its fragile population status.

1. Mating and Seasonality:

• Breeding typically occurs during the dry-to-wet season transition, between April and July, depending on the island.

• Males become more territorial and display subtle color changes—often showing pale pink cheeks and a flushed dewlap—as they seek mates.

• Male behavior includes head bobbing, dewlap extension, and occasional chasing or circling of females, but is generally less aggressive than that of Green Iguanas.

2. Copulation:

• Copulation occurs after brief courtship and includes cloacal alignment and a short period of mounting, often in vegetation or near nesting areas.

• Males may mate with more than one female, but dominance displays are less intense than in Iguana iguana.

3. Egg-laying:

• Females lay their eggs 4 to 6 weeks post-mating, digging nest burrows in sandy, sun-warmed soil.

• Clutch Size: Typically 6 to 20 eggs, depending on the size and health of the female.

• The eggs are white, leathery, and oval, and the female abandons the nest after laying.

4. Incubation and Hatching:

• Incubation lasts 90 to 110 days, with hatching timed to coincide with the rainy season, when vegetation is most abundant.

• Hatchlings emerge from the nest and disperse quickly, receiving no parental care.

5. Hatchlings:

• Neonates are bright green, around 4 to 6 in (10 to 15 cm) in length, and highly vulnerable to predators.

• Survivorship is low due to feral cats, rats, mongoose, and birds of prey.

6. Sexual Maturity:

• Lesser Antillean Iguanas reach sexual maturity at:
  – Females: ~3 to 4 years
  – Males: ~4 to 5 years

• Maturity is influenced by environmental quality and food availability.

With small clutch sizes, delayed maturity, and high hatchling mortality, the Lesser Antillean Iguana’s reproductive strategy makes it especially sensitive to population decline, contributing to its critically endangered status across much of its native range.

Lifespan

The Lesser Antillean Iguana is a long-lived tropical lizard, though its survival is increasingly threatened by invasive species and habitat loss. While individuals can live for decades under optimal conditions, the species’ fragile population dynamics mean few reach maximum age in the wild.

Lifespan in the Wild:
In undisturbed natural habitats, Lesser Antillean Iguanas may live 15 to 20 years, with some reaching up to 25 years. However, due to predation, disease, and human impacts, many individuals do not survive past their first few years.

Lifespan in Captivity:
In conservation centers and properly managed zoos, individuals have been known to live 20 to 25+ years. Extended longevity is achievable with access to UVB lighting, a calcium-rich diet, and medical oversight, though I. delicatissimais rarely kept outside of conservation programs due to its endangered status.

Threats to the Lesser Antillean Iguana:

• Invasive Predators: Feral cats, dogs, rats, and mongooses are major causes of juvenile mortality.

• Hybridization: Genetic swamping by introduced Green Iguanas (Iguana iguana) has caused loss of pure populations on several islands.

• Habitat Degradation: Urbanization, agriculture, and invasive plants reduce nesting and foraging areas.

• Climate Events: Hurricanes and droughts periodically devastate small island populations.

• Human Conflict: Hunting, road mortality, and poaching continue to threaten remnant populations on some islands.

Despite these pressures, the species’ slow metabolism, solitary habits, and low reproductive turnover have allowed it to persist in isolated refuges—though conservation intervention is now critical to ensure long-term survival.

Eating Habits

The Lesser Antillean Iguana is a strict herbivore, with a diet adapted to the seasonal vegetation of dry tropical forests and coastal scrub habitats on small Caribbean islands. Its arboreal feeding behavior, reliance on native plants, and role in seed dispersal make it a key ecological contributor within its limited range.

Diet:
Lesser Antillean Iguanas feed on a variety of leaves, flowers, fruits, and shoots, including:

• Sea grape (Coccoloba uvifera)

• Inga species (tropical legumes)

• Gumbo-limbo (Bursera simaruba)

• Cactus fruits, such as those from prickly pear (Opuntia)

• Native flowering shrubs and tree foliage during rainy seasons

They do not consume animal matter, even as juveniles, which sets them apart from many generalist iguanids.

Feeding Strategy:

• Diurnal forager: Active during the day, especially in the morning and late afternoon, when ambient temperatures allow efficient basking and digestion.

• They forage in trees and shrubs, often returning to known feeding trees.

• Use sharp, serrated teeth to clip tough leaves and grind fibrous plant material.

Digestive Adaptations:

• Possess a fermentative hindgut, where symbiotic bacteria help digest cellulose-rich foods.

• Their slow digestion and metabolism allow them to extract maximum nutrients from low-energy foliage.

• Regular basking is essential for raising internal temperature to support fermentation.

Water Intake:

• Hydration comes primarily from moist plant matter, such as young leaves and juicy fruits.

• During droughts, they may reduce activity and rely on internal moisture reserves stored in fat tissues.

The Lesser Antillean Iguana’s narrow dietary specialization, arboreal foraging, and reliance on native flora make it especially vulnerable to habitat degradation and invasive plant species, but also highlight its vital ecological role in maintaining island plant diversity.

Uniqueness

The Lesser Antillean Iguana is one of the rarest and most genetically distinct iguanas in the world. Endemic to the Lesser Antilles, it is known for its graceful appearance, ecological importance, and fragile conservation status. Its survival is a symbol of island biodiversity under threat.

Island-Endemic Elegance:
Found only on a few islands—including Dominica, Saint Barthélemy, and Anguilla—this species is completely absent from the mainland. It evolved in island isolation, resulting in a slimmer frame, smoother scales, and softer colorationcompared to its continental relatives.

Absence of Key Iguana Traits:
Unlike the Green Iguana, it lacks the large subtympanic cheek scale, large jowls, and prominent dorsal spines—giving it a more refined and less armored appearance. These distinctions are not just visual—they reflect deep genetic divergence.

No Hybrid Appetite:
The Lesser Antillean Iguana is strictly herbivorous throughout life, unlike many iguanas that are opportunistic omnivores as juveniles. Its specialized plant-based diet makes it highly adapted to native forest vegetation—but also vulnerable to habitat change and invasive plants.

Ecological Keystone and Seed Disperser:
By foraging on native fruits and flowers, this iguana plays a critical role in seed dispersal and forest regeneration, especially on small, fragile islands where other herbivorous reptiles are absent or extinct.

Genetic and Conservation Priority:
Hybridization with the introduced Green Iguana has led to genetic swamping on many islands. Conservationists now prioritize this species for island-by-island genetic protection, biosecurity, and reintroduction, recognizing it as one of the top reptile conservation priorities in the Caribbean.

Cultural Identity and Conservation Symbol:
On islands like Dominica, the Lesser Antillean Iguana is a national emblem, featured in educational campaigns, conservation stamps, and ecotourism promotions. Its story underscores the conflict between native and invasive species, and the challenge of preserving island endemics in the face of globalization.

With its graceful form, island endemism, and high conservation value, the Lesser Antillean Iguana is not only one of the most unique lizards in the West Indies, but also one of the most urgently protected.