Caring for Green Iguanas

Iguanas are among the most popular pet reptiles. They love to bask in the sun or under an ultraviolet light, and they enjoy a diet of leafy greens and vegetables. Many people don’t realize that iguanas can grow to be quite large, exceeding 6 ft (1.8 m) in length. Iguanas should be properly socialized when they are young to ensure that they can be handled as adults. They require specialized housing and regular veterinary care and may not be a suitable pet for everyone.

Biological Facts

  • The green iguana (Iguana iguana) is a tree-dwelling lizard native to Mexico and South America.
  • Captive life span: 9 to 12 years of age
  • Weight (adult): 5 to 20 lb (2.3 to 9 kg)
  • Sexual maturity:3 to 4 years of age
  • Incubation: 73 to 93 days
  • Average clutch size: 20 to 40 eggs (hatchability may approach 100%)


  • Green iguanas seek heat; in the wild, they spend many hours basking in the sun.
  • They are solitary by nature, except during the breeding season.
  • They are highly territorial and should be housed alone.
  • They can become accustomed to human touch, but excessive handling may cause stress.


  • Green iguanas eat fresh, dark, leafy greens such as kale, escarole, endive, collard greens, mustard greens, turnip greens, and leaf lettuce. Do not feed them iceberg lettuce because it lacks calcium and other nutrients.
  • They also eat vegetables such as diced yellow squash, zucchini, and grated carrots.
  • They can be fed commercially available iguana pellets.
  • Feed your iguana only low-protein foods because too much protein in the diet may cause kidney damage.
  • Dust a phosphorus-free calcium supplement over greens daily for juveniles (younger than 2 years of age) and once or twice weekly for adults.
  • Provide fresh water daily.


  • The enclosure should be large enough for the iguana to move around comfortably and climb and should mimic the natural environment as closely as possible.
    • Maintain a temperature of 70°F to 77°F (21.1°C to 25°C) in the coolest area and up to 90°F to 95°F (32°C to 35°C) in a basking area.
    • Use infrared lamps and ceramic heat emitters rather than under-the-cage heat pads or hot rocks, which can cause severe burns.
    • Provide ultraviolet (UV) light in the UVB spectrum, as lack of UVB radiation can cause vitamin D deficiency, inhibit calcium absorption, and result in metabolic bone disease of nutritional origin.
    • UVB bulbs come in two forms: fluorescent and mercury vapor. Replace fluorescent bulbs every 6 to 9 months because even though they continue to produce visible light, they lose UVB output over time. Mercury vapor UVB bulbs continue to produce UVB radiation and need to be replaced only when they stop producing light.
    • Place UVB lights within 12 to 18 inches of the iguana’s basking area. The bulb should not be blocked by glass or plastic, which filter out beneficial rays.
  • Provide reptile carpet or newspaper for bedding, and avoid bark and wood chips, which may cause intestinal blockage if ingested.
  • Provide plenty of vertical space for climbing, with branches and platforms for perching.
  • Provide fresh water in a large pan to allow soaking and stimulate defecation, and be sure to change the water daily and/or when it is soiled.

Preventive Care

  • A routine physical examination should be performed every 6 to 12 months. Consult a veterinarian with experience treating reptiles if you have questions or concerns about your iguana’s health.
  • An annual fecal examination should be performed to check for parasites.
  • Blood tests should be performed as recommended by your veterinarian.

Common Medical Disorders

  • Abscesses (pus-filled swellings)
  • Egg binding in females
  • Internal and external parasites
  • Kidney disease
  • Nutritional secondary hyperparathyroidism (metabolic bone disease)
  • Prolapsed hemipenis in males
  • Thermal burns