Iguanas
A green iguana reaches six feet and lives twenty years, which is the fact most often missed at purchase. Herbivorous, and it has a third eye on top of its skull.
Overview
The green iguana is an arboreal, herbivorous lizard of Central and South America that lives high in the tree canopy, and it is the animal most often bought small and given up large. ADW gives around 2 m head to tail, averaging 1.75 m, at four to six kilograms and sometimes eight.
A six foot lizard that lives more than twenty years in captivity needs a purpose built space rather than a room shared with it, and that requirement arrives about three years after the animal does.
Temperament
Not a tame animal by default. Iguanas are strong, they have a whipping tail, claws that do real damage, and adult males become territorial and can be genuinely dangerous during breeding season.
They can be socialised with consistent, patient handling, and many are calm with the person who raised them and with nobody else. A parietal eye on top of the head reads solar energy, and the pendulous dewlap under the throat is used in display and in thermoregulation. Both are worth understanding, because a displaying iguana is communicating rather than posing.
Care and grooming
Leafy greens, and no animal protein for an adult. Iguanas digest cellulose in a sacculated colon using gut microflora, which is where most of their digestion happens, and a protein rich diet damages the kidneys over years rather than causing anything visible now. Juveniles take some insects for protein in the first two or three years.
UVB is required and it must be strong. In green iguanas specifically, UVB exposure rather than dietary vitamin D3 appears to be what actually prevents bone fractures.
Living and exercise
A purpose built space, roughly 6 by 6 by 8 feet, with climbing structure at height, a basking spot at 95 F, ambient around 85 F and humidity at 65 to 75 percent. Juveniles sit low in the canopy and mature animals sit high, so the useful space is vertical.
All Iguana species are listed on CITES Appendix II. Introduced populations are established in southern Florida and Hawaii, which is the direct result of released and escaped pets.
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