Green Iguana

Adults need a floor-to-ceiling, custom enclosure, not an aquarium. Aim for a minimum of about 2.4 to 3.6 m long x 1.8 m tall x 1.2 m deep (roughly 8 to 12 ft x 6 ft x 4 ft); vertical height matters most because iguanas are arboreal. Many keepers convert a whole room or a large closet. Furnish with sturdy, secured climbing branches at varied heights, broad basking shelves under the heat and UVB, and elevated hides. Provide a large, shallow water container big enough to soak in, cleaned daily. Substrate should be safe and easy to disinfect: newspaper, reptile carpet, or large-particle orchid bark. AVOID sand, fine gravel, wood shavings, cedar, and pine, which cause gut impaction and respiratory irritation. Babies can start smaller but you must plan and budget for the adult enclosure from day one.

Strict herbivore; feed only plants, fresh daily. Base roughly 70 to 80 percent on calcium-rich dark leafy greens: collard, mustard, turnip and dandelion greens, escarole, endive, chicory, and watercress. Add about 15 to 20 percent other vegetables (squash, green beans, bell pepper, snap peas, grated sweet potato) and no more than 5 to 10 percent fruit as a treat. Dust salads with a plain calcium (no phosphorus) supplement most feeds, use a calcium-with-D3 and a reptile multivitamin only once or twice weekly, aiming for a dietary calcium-to-phosphorus ratio near 2:1. AVOID entirely: all animal protein (meat, insects, eggs, dog or cat food), dairy, and human processed food; these cause kidney disease, gout, and dangerous hypervitaminosis D. Feed spinach, chard, beet greens, kale, and rhubarb only sparingly or not at all because their oxalates or goitrogens bind calcium or interfere with the thyroid. No avocado, no onion or garlic, no iceberg lettuce (nutritionally empty).

Provide a clear thermal gradient. Basking spot: 35 to 38 C (95 to 100 F) measured at the surface where the iguana sits (do not let it exceed about 40 C). Warm ambient side: 29 to 32 C (85 to 90 F). Cool side: 26 to 29 C (80 to 85 F). Night-time may drop but must stay above about 21 to 24 C (70 to 75 F). Use a hygrometer and keep humidity around 70 percent (acceptable 60 to 80 percent), with daily misting; too-dry air causes shedding and kidney problems, too-wet stagnant air causes skin and respiratory infection. UVB is essential to prevent metabolic bone disease: use a high-output linear UVB tube (T5 HO, 10 to 12 percent / Ferguson Zone 3 to 4, roughly UVI 3 to 6 at the basking site), positioned so the animal can move to within about 30 cm through open air (mesh and glass block UVB). Run lights on a 12-hour on / 12-hour off cycle and replace UVB tubes every 6 to 12 months per the manufacturer even though they still emit visible light. Use guarded ceramic or basking heat sources on thermostats; never an unguarded bulb the animal can touch.

Best kept singly. Iguanas are not social and do not need companions; cohabiting often leads to bullying, stress, and injury, especially two males or a male with a female he harasses. Mature males are territorial and can become aggressive, particularly during breeding season, and may even redirect aggression toward their keeper. Sexing: adult males develop larger jowls and dewlaps, bigger femoral pores on the underside of the thighs, and paired hemipenal bulges at the tail base; reliable sexing is easiest in adults and can be confirmed by an exotics vet. Regular gentle handling from a young age helps tameness, but never grab or restrain by the tail, which can autotomize (drop) or whip.

Give vertical complexity: multiple branch levels, ramps, and platforms to climb and survey from height, which reduces stress. Rotate basking perches and provide visual barriers and secure hides. Vary the salad with different greens and occasional edible flowers (hibiscus, dandelion) for foraging interest, and scatter or hang food to encourage natural browsing. Supervised time in a safe, warm, iguana-proofed space and access to natural unfiltered sunlight (in a secure outdoor pen when weather allows) are excellent enrichment. A large soaking tub for bathing supports hydration and shedding.