Mona ground iguana

The largest herbivore and seed disperser on its island

Mike Morel, U. S. Fish and Wildlife Service


Mona ground iguana

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The largest herbivore and seed disperser on its island

Population 4,000 – 5,000

Found only on Mona Island, a small limestone island between Puerto Rico and the Dominican Republic, it is the largest native land animal in the region and an extraordinary example of island evolution. Often called the “Caribbean dragon,” this impressive iguana is a living link to a prehistoric past, perfectly adapted to survive in the hot, rocky, and arid conditions of its isolated home. Its presence on Mona Island adds a touch of ancient majesty to the sun-scorched landscape, where it basks on cliffs and limestone ledges, blending almost seamlessly into its surroundings.

Physically, the Mona ground iguana is both powerful and elegant. Their tough, leathery skin is usually gray or brown, sometimes tinged with soft blues, greens, or rusty oranges that shimmer in the tropical sun. A row of pointed spines runs down the back, giving the lizard its distinctive dragon-like appearance. Their strong limbs and sharp claws are perfect for climbing and digging, while their muscular tails—lined with ridged scales—serve as both balance tools and defensive weapons. When threatened, they can deliver a surprisingly painful tail whip, a technique that has helped them fend off predators for thousands of years. Despite their rugged look, these iguanas are primarily herbivorous, feeding on leaves, flowers, and fruits of native shrubs and cacti, especially the prickly pear cactus, which provides them with both food and water in the island’s dry environment.

Behaviorally, the Mona ground iguana is as fascinating as it is hardy. These reptiles are diurnal, spending much of the day basking in the sun to warm their bodies before venturing out to feed. They dig burrows or find shelter in crevices to escape the midday heat and predators, including feral pigs and cats introduced to the island. During the breeding season, males become territorial and engage in elaborate displays—head-bobbing, push-ups, and tail movements—to court females or challenge rivals.

Distribution

Country
Population est.
Status
Year
Comments
Puerto Rico
4,000-5,000
Official estimate
CR
2019

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Terrestrial / Aquatic

Altricial / Precocial

Polygamous / Monogamous

Dimorphic (size) / Monomorphic

Active: Diurnal / Nocturnal

Social behavior: Solitary / Pack / Herd

Diet: Carnivore / Herbivore / Omnivore / Piscivorous / Insectivore

Migratory: Yes / No

Domesticated: Yes / No

Dangerous: Yes / No