50 Fun Facts About Iguanas

In which US state do cold snaps stun wild green iguanas so badly that they tumble from their perches?

Florida's feral iguanas slip into a torpor on unseasonably cold nights and lose their grip on the branches, as happened in January 2008, 2010 and 2018.

What do marine iguanas regularly sneeze out through their nostrils?

Salt is filtered from a marine iguana's blood by glands at the nostrils and expelled in a sneeze, which can turn its head white and crusty.

Green iguana meat is eaten in Central America under a nickname comparing it to which other meat?

Chicken is the comparison: the nickname gallina de palo means 'chicken of the tree', and people in the region have eaten iguanas for about 7,000 years.

Which movie monster was reimagined in a 1998 Hollywood film as an iguana mutated by nuclear fallout?

Godzilla hatches in the 1998 film from an iguana nest exposed to fallout from a nuclear test in French Polynesia, then heads for New York City.

What can marine iguanas do to their own bodies to survive when El Niño wipes out their food?

Shrink in length is what they do: some marine iguanas become up to 20% shorter during El Niño famines, then grow back once food returns.

What nickname is given to the pale light-sensing organ on the top of a green iguana's head?

Third eye is the nickname of the parietal eye, which cannot form images but senses changes in light and dark and can detect movement overhead.

Which body part can a green iguana snap off to escape a predator's grip and later regrow?

Its tail can break away when grabbed, letting the iguana escape and eventually regenerate a new one; it also works as a whip that delivers painful strikes.

Which punk rock singer got his stage name from the Iguanas, a high-school band he drummed for?

Iggy Pop, born James Osterberg, was nicknamed Iggy by a later band, the Prime Movers, because he had played in the Iguanas.

The dinosaur Iguanodon was named in 1825 because which of its fossil parts resembled an iguana's?

Teeth gave Iguanodon its name, which means 'iguana-tooth'; geologist Gideon Mantell chose it for the second dinosaur ever formally named.

Marine iguanas are the only living lizards that forage in the ocean; what makes up almost all of their diet?

Algae growing on rocks make up nearly everything a marine iguana eats, and it can dive as deep as 30 metres and stay under for up to an hour to graze.

Which naturalist, meeting marine iguanas in 1835, described them as disgusting, clumsy lizards?

Charles Darwin was revolted by the animals' looks yet observed them closely, and noted that somebody had nicknamed them imps of darkness.

Marine iguanas live only on the Galápagos Islands, which form a province of which South American country?

Ecuador governs the islands, which lie around 1,000 km west of its mainland and are protected as a national park and marine reserve.

Which BBC nature series made a famous 2016 chase out of marine iguanas fleeing racer snakes?

Planet Earth II showed the chase in its 'Islands' episode, narrated by David Attenborough, and reviewers singled it out as a highlight of the whole series.

Green iguanas have sharp colour vision and can see which kind of light that is invisible to humans?

Ultraviolet wavelengths are visible to green iguanas thanks to special double-cone cells, yet they have few rod cells and see poorly in dim light.

The black iguana of Mexico and Central America holds which record among all the world's lizards?

Fastest sprint goes to the black iguana: one was clocked at a burst speed of 34.6 km/h, the highest speed ever reported for a lizard.

What colour is the rare land iguana found only on Wolf Volcano in the Galápagos Islands?

Pink skin with dark stripes marks this iguana, which was first spotted in 1986 and only recognised as a separate species in 2009.

Green iguanas grow up to 1.7 metres long on a diet made up mostly of what?

Leaves and flowers, along with fruit and growing shoots, feed green iguanas, which are primarily herbivores and browse on upwards of 100 kinds of plant.

Which flap of skin under the throat do green iguanas extend to court mates and regulate body temperature?

Dewlap is the name of the throat flap, which a cornered iguana also displays while it stiffens, puffs up its body and hisses at the aggressor.

Which South Pacific nation has native iguanas, an ocean away from their closest relatives in the Americas?

Fiji has native banded iguanas, yet their closest living relatives are in the Americas, about 10,000 km away across the Pacific.

The endangered blue iguana, rescued by captive breeding, lives wild on only which Caribbean island?

Grand Cayman had fewer than 15 wild blue iguanas left by 2003, before hundreds of captive-bred animals were released into a preserve on the island.

Which Caribbean island's iguana was thought extinct until a hog hunter's dog chased one into a log in 1990?

Jamaica's iguana had been believed extinct since 1948, and the animal the dog cornered in the Hellshire Hills was taken to the Hope Zoo.

The rhinoceros iguana, named for the horn-like bumps on its snout, is native to which Caribbean island?

Hispaniola, the island shared by Haiti and the Dominican Republic, is home to the rhinoceros iguana, whose bony snout bumps resemble a rhino's horn.

What do newly hatched marine iguanas eat to pick up the gut bacteria they need for digestion?

Adults' droppings are a young marine iguana's main food for its first months, because they pass on the microbes it needs to digest the adult diet.

Which American playwright wrote The Night of the Iguana, a drama that premiered on Broadway in 1961?

Tennessee Williams set the play at a cheap hotel on the coast of Mexico, and John Huston turned it into an Oscar-winning film in 1964.

Isa the Iguana is one of the hero's animal friends in which Nickelodeon preschool cartoon?

Dora the Explorer gave its young adventurer a monkey sidekick, Boots, and an iguana friend, Isa, who was voiced by three actresses over the show's run.

In which 2016 animated musical film is the theatre owner's elderly assistant, Miss Crawly, an iguana?

Sing gets its plot from a typo by Miss Crawly, which adds two zeros to a contest flyer and turns a $1,000 prize into $100,000.

Through which European language did the Caribbean word 'iwana' reach English as 'iguana'?

Spanish speakers borrowed the name from the Taíno, an Arawak-speaking people of the Caribbean, whose word for the lizard was iwana.

Which desert lizard of the iguana family wedges into a rock crevice and inflates its lungs when disturbed?

Chuckwalla lizards puff up until they are jammed in tight, yet the Seri and Timbisha Shoshone peoples still counted them an important food.

The Galápagos land iguana gets most of its moisture by eating which plant, nearly 80% of its diet?

Prickly pear cactus supplies the bulk of the land iguana's water because fresh water is scarce on the islands, though it drinks from rain pools in the wet season.

Which US island territory proposed in 2012 to cull its four million green iguanas and sell them for meat?

Puerto Rico's iguanas descend from animals introduced from South America, and the island now treats the very common lizard as an invasive nuisance.

Which US state threatens green iguana owners with up to three years in jail to protect its ecosystem?

Hawaii strictly regulates importing or possessing the species, and violators can also be fined up to $200,000.

Marine iguanas become more watchful when they overhear the alarm call of which Galápagos bird?

Mockingbird alarm calls signal that a Galápagos hawk is about, a predator of both animals, so the iguanas eavesdrop on a different species.

Sally Lightfoot crabs sometimes clamber over marine iguanas in the Galápagos to feed on what?

Ticks and mites are picked off by the crabs in an apparent cleaning partnership: the iguanas shed their parasites and the crabs get a meal.

Only about 5% of marine iguanas dive offshore for food; which members of the colony are they?

The largest males do the offshore diving, while females and smaller animals wait for low tide and graze on rocks the sea has uncovered.

Which signal do green iguanas use to greet one another and to court a possible mate?

Head bobs serve as both a greeting and a courtship signal, and bobbing also counts among an iguana's dominance displays.

Which naturalist gave the green iguana its first scientific description in 1758?

Carl Linnaeus, the Swedish botanist who popularised two-part scientific names, catalogued the species, whose modern name, Iguana iguana, says the same word twice.

The desert iguana lives in the Sonoran Desert and which other desert of the American Southwest?

Mojave heat, in the desert around Las Vegas, suits the desert iguana, which stays out after other lizards have retreated to burrows and seeks shade only once its body passes 40 °C.

Male green iguanas release a territory-marking scent from large pores found on which part of the body?

Thighs carry the scent glands, called femoral pores, on their underside; females have them too, but theirs are smaller.

Some 800,000 green iguanas were imported into the United States in 1995 alone to supply which business?

The pet trade created the demand, yet the lizards are so demanding to care for that many die within a few years of being bought.

The desert iguana's scientific genus name, Dipsosaurus, combines two Greek words that together mean what?

Thirsty lizard is the meaning, built from the Greek dipsa and sauros; Edward Hallowell gave the species the name two years after it was first described.

How did at least 15 green iguanas reach the island of Anguilla in 1995, colonising it for the first time?

On storm-felled trees is the answer: after two hurricanes, a raft of uprooted trunks carried them about 320 km from Guadeloupe, probably in three weeks.

What is the biggest reason green iguanas have caused the Lesser Antillean iguana to decline on many islands?

Mating with it creates hybrids, and that mixing has done more than anything else to push the critically endangered native towards disappearing.

Male green iguanas appear to be the only reptiles known to do what for females when predators threaten?

Use their bodies as cover is right: males in a group often place themselves between females and danger, something reported in no other reptile species.

Why does the dark colour of most marine iguanas help them after a swim in the cold sea?

It soaks up heat fast, which shortens the sluggish spell after a dive, when a chilled iguana can barely move and is easy prey.

What do marine iguanas use to hold onto underwater rocks in strong currents while they feed?

Long, sharp claws anchor a feeding marine iguana to the rock, and it also uses them to pull itself forward along the sea bottom.

In Panama, green iguanas have been observed sharing their nest sites with which much larger reptile?

American crocodiles nest alongside the iguanas in Panama, and in Honduras the same sharing has been seen with spectacled caimans.

The usually dark grey blue iguana turns a brighter blue mainly in which situation?

Near other iguanas, the animal turns blue to signal and establish territory; left alone, it stays a grey that matches the karst rock of its landscape.

The Utila iguana of Honduras is the only iguana that lives exclusively in which habitat?

Mangrove swamps are the critically endangered lizard's whole world, earning it the nickname swamper; competition from larger species pushed it there.

Despite the species' name, green iguanas from the western region of Costa Rica are which colour?

Red animals live in western Costa Rica, while green iguanas in Mexico appear orange and those in Peru can look bluish.

What happens to a marine iguana's heart rate when the animal dives into cold water to feed?

It drops sharply, to about 30 beats a minute against roughly 100 on warm land, which reduces blood circulation and helps the diver conserve its warmth.