Green Iguana Field Guide — Iguana iguana in Florida

Despite the name, the green iguana isn’t always green, and despite being one of the most conspicuous reptiles in South Florida, it doesn’t belong here at all. Iguana iguana is an established invasive — a tropical lizard that arrived through the pet trade and now suns itself on seawalls from Key West to Palm Beach, occasionally falling out of the sky.

ID at a Glance

The green iguana is hard to mistake for anything else native, mostly because nothing native looks like it.

• Size: Adults commonly 4–5 ft including the long, banded tail, and 8–17 lb. The tail accounts for over half the total length.
• Color: Bright green in juveniles, but adults range through grey, brown, dull green, and — in breeding males — striking orange. “Green iguana” is more a name than a reliable field mark.
• Crest: A row of tall, spiny crest scales runs down the back and tail, most pronounced in males.
• Dewlap: A large, flat throat fan (the dewlap) hangs below the jaw, used in display and thermoregulation.
• Cheek scale: A distinctive large, round “subtympanic” scale sits on the cheek below the ear — a reliable close-range mark.
• Tail: Long, banded, muscular, and whip-like. It’s a defensive weapon and a swimming aid.

Taxonomy

Iguana iguana belongs to Family Iguanidae, the New World iguanas. It is native to Central and South America — from Mexico south through the Amazon basin to Paraguay — plus several Caribbean islands. Florida sits far outside that native range. Everything you see basking on a Miami canal bank is the descendant of escaped or released pets and animals that hitchhiked in on cargo.

Range and Habitat in Florida

Green iguanas are not native to Florida; they are an introduced, established invasive concentrated in the warm southern third of the state.

Core range: Miami-Dade, Broward, and Palm Beach counties, plus the Florida Keys. Populations are densest along the urban coastal corridor — anywhere with water, sun, and landscaping.

Preferred habitat: Canal banks, seawalls, docks, golf courses, parks, and suburban yards. They are arboreal and semi-aquatic, equally at home in a backyard mango tree or diving into a canal.

Spreading north: As Florida winters trend warmer, the species has been pushing up both coasts. Hard freezes are still the main brake on how far north it can establish.

Behavior and Ecology

Diet: Largely herbivorous — leaves, flowers, and fruit. In Florida this makes them a landscaping menace, stripping ornamental plants, gardens, and native vegetation. They are also strong climbers and excellent swimmers, diving into canals and using the tail to propel themselves.

Basking: Being ectothermic, they spend hours soaking up sun on seawalls, docks, roofs, and branches. A startled iguana will crash dramatically off a seawall into the water and swim away underwater.

Burrowing: This is where the iguana graduates from nuisance to genuine problem. They dig long burrows that erode canal banks, undermine seawalls and sidewalks, and can compromise building foundations. Their droppings foul pools, docks, and patios, and are a potential source of salmonella.

Defense: Males grow large and territorial, especially in breeding season when they turn orange. They aren’t aggressive toward people by nature, but a cornered animal can lash with its tail, scratch, and bite. The damage is mostly to property, not people.

The “Raining Iguanas” Phenomenon

South Florida is the only place in the United States where the weather forecast occasionally warns of falling iguanas. It is real, not a joke.

Green iguanas are tropical and cold-blooded. When temperatures drop into the 40s°F (single-digit °C), their metabolism slows, they go torpid, and they lose the muscular grip that keeps them clamped to tree branches overnight. The result: stunned iguanas dropping out of trees, sometimes thudding onto cars, sidewalks, and pool decks. National Weather Service offices in Miami have genuinely included “falling iguana” notes in cold-snap advisories.

The critical caveat: a cold-stunned iguana usually isn’t dead — just immobilized. As temperatures rise it thaws and reanimates. People who scooped up “dead” iguanas into their cars have learned this the hard way when the animal woke up. Give a torpid iguana room and let the sun do its work.

Conservation Status

Globally, Iguana iguana is listed as Least Concern by the IUCN — it is widespread and abundant across its native range.

In Florida, however, conservation runs in the opposite direction. The state classifies the green iguana as an invasive species, and the goal is removal, not protection. Florida encourages humane removal:

• Homeowners may humanely remove green iguanas from their own property year-round, no permit needed.
• They may also be removed humanely from 25 designated public lands without a permit.
• Keeping or releasing green iguanas as new pets is prohibited.

The underlying message is consistent: never release a pet reptile into the wild. Florida’s iguana problem exists because people did exactly that. Always follow current FWC rules and humane-killing guidance.

Where to See It

You will not have to look hard. In South Florida, green iguanas are among the easiest large reptiles to find.

Seawalls and canal banks: Miami and Fort Lauderdale waterfront neighborhoods are reliable — iguanas line the seawalls in the morning sun.

Key Biscayne: Parks and shorelines host conspicuous populations.

Golf courses and city parks: Open grass plus water plus ornamental plantings is iguana heaven.

Suburban yards: Almost any South Florida backyard with fruit trees and a canal will have residents.

Timing: Morning basking is the easiest window — look along the water’s edge. The signature South Florida sighting is an iguana exploding off a seawall and diving into a canal the instant you get too close.

Interesting Facts

• The “raining iguanas” forecast is a genuine South Florida weather phenomenon, not local folklore.
• They are powerful swimmers and will dive straight into a canal to escape, using the tail like a paddle and staying submerged.
• Their burrowing isn’t just unsightly — it is a documented infrastructure problem, eroding seawalls and undermining foundations along Florida’s canals.
• Breeding males turn orange, so the “green” iguana sunning on a seawall may be a vivid tangerine.