Green iguanas fall fifty feet unhurt and see ultraviolet light
Iguana iguana is a big arboreal herbivore native from southern Mexico through Brazil and Paraguay, now invasive across Florida, Hawaii, and far beyond. Adults often stretch one point two to one point seven metres. They bask with tetrachromatic vision that includes ultraviolet, guided by a parietal "third eye" on the skull.
Linnaeus named the species in seventeen fifty-eight; later subspecies mostly collapsed into regional variants, though recent genetics still argue over cryptic lineages such as I. rhinolopha and Antillean horned forms. Phylogenies place the origin in South America with later spread through Central America and the Caribbean. The English name traces to Taíno iwana via Spanish. Typical snout-vent length is thirty to forty-two centimetres; heavy males can top eight kilograms and two metres. Spines, a breakaway whip tail, and a dewlap for heat and display arm the climber.
Leaf-shaped serrated teeth shred foliage—and inspired the dinosaur name Iguanodon. A high-potassium plant diet forces nasal salt glands to dump excess sodium and potassium as urate salts, bird-style. Colour is not always green: Peru blues, Caribbean lavenders, Costa Rican reds, and Salvadoran blue juveniles all occur. Females lay twenty to seventy-one eggs yearly and leave; hatchlings emerge after ten to fifteen weeks and stay in family groups a year, with males reportedly shielding females—rare among reptiles. They can drop fifteen metres and land fine, swim with trailing legs and strong tail beats, and colonised Anguilla in nineteen ninety-five after a hurricane rafted them ashore.
Popular pets still demand space, heat, and light many keepers underestimate. Feral colonies thrive in Puerto Rico, South Florida, Texas's Rio Grande Valley, and islands from Singapore to the Virgin Islands, while native communities also farm them for food.
Source: Green iguana
