Most iguanas eat plants: leaves, flowers and ripe fruit. Green iguanas eat mainly leafy plants and fruit, marine iguanas eat almost only seaweed, and desert iguanas love yellow creosote flowers. Spiny-tailed iguanas also eat insects and small animals. Vets say pet iguanas need mostly dark leafy greens, with very little fruit or animal protein.
Iguanas quick facts
- Marine iguanas are the only lizards that feed in the sea.
- Baby green iguanas eat adult droppings to collect the microbes that digest plants.
- One desert iguana was seen eating yellow tape.
- Marine iguanas can shrink when food runs short, then grow again.
- Floridians collected 5,195 cold-stunned iguanas after a February 2026 cold snap.
Iguana diets at a glance
Most iguanas are plant-eaters. They munch leaves, flowers and fruit. But some iguanas eat seaweed, some love yellow flowers, and a few will eat almost anything they can catch.
This guide covers what wild iguanas eat, species by species, and how they digest tough plants. It also explains what pet iguanas should eat, and how to stay safe around them. The facts come from Animal Diversity Web, the Galápagos Conservancy, Florida wildlife officials, the University of Florida, vets and the CDC.
| Iguana | Main food |
|---|---|
| Green iguana | Leaves and ripe fruit |
| Marine iguana | Seaweed |
| Desert iguana | Buds, leaves and yellow creosote flowers |
| Galápagos land iguana | Low plants, fallen fruit and cactus pads |
| Black spiny-tailed iguana | Insects when young, then mostly plants plus small animals |
| Rhinoceros iguana | Leaves, fruit, flowers and seeds |
Iguanas are mostly plant-eaters
Animal Diversity Web says adult iguanas are plant-eaters. They mainly eat leaves, fruit and flowers.
There are about 35 species of iguana. They live in tropical America, the south-western United States, the Caribbean, the Galápagos Islands and Fiji. Their diets change with where they live.
“Mostly” is an important word. Some iguanas do eat animals now and then. A few eat them often. The sections below show how much variety there is.
What do green iguanas eat?
Green iguanas are the best known. Animal Diversity Web says they mostly eat green leafy plants and ripe fruit. In the wild, they live in the treetops of tropical forests, from Mexico to Paraguay and south-east Brazil.
Wild green iguanas occasionally eat a little carrion, which means dead animals, or small invertebrates. Young green iguanas need more protein in their first two to three years. They may eat insects and spiders.
Green iguanas are big for lizards. Animal Diversity Web says adults usually weigh 4 to 6 kg (9 to 13 lb), and they can grow to about 2 metres (6.5 feet) long including the tail. The University of Florida says the tail can make up three-quarters of that length.
How iguanas digest tough leaves
Leaves are hard to digest. Green iguanas have a clever solution. Animal Diversity Web says they barely chew. They use their tongues to move food and bite off pieces small enough to swallow.
The real work happens in the gut. Green iguanas digest leaves in a pouched part of the large intestine. There, tiny microbes break down the tough plant fibre. This is called hindgut fermentation.
Babies have to collect those microbes. Animal Diversity Web says baby green iguanas eat droppings from adults. This gives them the helpful gut microbes they need to digest plants.
Warmth matters too. Iguanas are cold-blooded, so they need heat to digest. Green iguanas feed best at about 25 to 35°C (77 to 95°F).
What do marine iguanas eat?
The Galápagos Conservancy says marine iguanas are the only lizards that feed in the sea. Animal Diversity Web says they eat almost nothing but seaweed.
They graze seaweed on rocks, in shallow water, or by diving. Larger marine iguanas dive for seaweed at high tide. Smaller ones feed on rocks uncovered at low tide.
Their bodies suit this diet. A short, blunt nose helps them scrape seaweed off rocks, and a flat tail pushes them through the water.
Seaweed is salty, so marine iguanas swallow lots of salt. A special gland connected to their nostrils removes it. They sneeze out salty crystals.
When the seaweed runs out
Some years the ocean warms in an event called El Niño. The seaweed changes, and food runs short. The Galápagos Conservancy says marine iguanas can actually shrink in those years, then grow again when food returns.
Hard times can still be deadly. Animal Diversity Web says many marine iguanas died when the seaweed changed during the 1982 to 1983 El Niño.
Today the Galápagos Conservancy thinks there are 200,000 to 300,000 marine iguanas. They can live for up to 60 years, and they are found only on the Galápagos Islands.
Galápagos land iguanas
Marine iguanas share their islands with land iguanas. The Galápagos Conservancy says land iguanas eat low-growing plants, shrubs, fallen fruit and cactus pads.
They are large lizards. Land iguanas can be more than 0.9 metres (3 feet) long, and males can weigh up to 13.6 kg (30 lb).
What do desert iguanas eat?
Desert iguanas live in the Sonoran and Mojave deserts of the south-western USA and northern Mexico. Animal Diversity Web says more than 90% of their diet is plants.
They eat buds, leaves and flowers. In spring, they especially love the yellow flowers of the creosote bush. Desert iguanas sometimes eat insects too.
They seem to be attracted to the colour yellow. Animal Diversity Web reports that one was even seen eating yellow tape.
Desert iguanas are small, about 33 to 36 cm (13 to 14 inches) long. They love heat and are most active at about 40°C (104°F). They can handle 46°C (115°F), but 55 to 60°C (131 to 140°F) kills them.
Spiny-tailed iguanas eat animals too
Spiny-tailed iguanas break the plant-eater rule. Animal Diversity Web says young black spiny-tailed iguanas mostly eat insects. Adults switch mainly to plants.
Adults still catch small animals. They eat rodents, bats, frogs, birds and insects when they can.
In Florida, where they are not native, the list is even longer. The Florida Museum of Natural History reports that a 2009 study found them eating leaves, flowers, fruit, insects, spiders, crabs, fish, rodents, baby sea turtles, lizards, birds, eggs and bats. They even ate their own eggs and young.
The Florida Museum says black spiny-tailed iguanas in Florida number in the tens of thousands.
Rhinoceros iguanas help plants spread
Rhinoceros iguanas eat leaves, fruit, flowers and seeds. Animal Diversity Web says they occasionally eat insects, land crabs or dead birds and fish.
A rhinoceros iguana will defend a good fruiting bush from other iguanas. And it gives something back. Seeds often pass through its gut unharmed, so the iguana helps plants spread to new places.
Green iguanas in Florida
Green iguanas are not native to Florida. The Florida Fish and Wildlife Conservation Commission (FWC) says they were first reported there in the 1960s. The University of Florida says a pet dealer released more than 300 near Miami in 1964.
In Florida, the FWC says green iguanas eat the shoots, leaves, flowers and fruit of plants such as nickerbean, firebush and hibiscus. Young ones also eat insects and tree snails. Adults sometimes eat bird eggs and carrion.
Gardeners are not happy. The University of Florida says iguanas eat orchids, other flowers and fruit such as berries, figs, mangoes, tomatoes, bananas and lychees. They usually avoid citrus and tough, thick-leaved plants such as oleander and milkweed.
The FWC added green iguanas to Florida’s Prohibited Species list on 29 April 2021. After a cold snap on 1 and 2 February 2026, residents brought 5,195 cold-stunned green iguanas to FWC collection points.
What should pet iguanas eat?
Pet iguanas need a careful diet. VCA Animal Hospitals says 80 to 90% of a pet iguana’s food should be dark green leafy vegetables, such as collard and mustard greens.
Fruit should be less than 20% of the diet, VCA says, because most fruit is mainly water and low in nutrients. Iceberg lettuce is a poor food for the same reason.
Some greens need limiting. VCA says spinach, Swiss chard and beet greens stop iguanas absorbing calcium. Young pet iguanas need calcium powder on their food 4 to 5 times a week, and adults once or twice a week.
Animal protein should be very limited. VCA says insects should make up less than 5% of an adult green iguana’s diet. Never feed iguanas dog or cat food. It has far too much protein, fat, phosphorus and vitamin D. Pet iguanas should always have fresh, clean water.
Staying safe around iguanas
Iguanas can carry germs. The CDC says reptiles, including iguanas, often carry Salmonella germs, even when they look healthy.
The CDC says children under 5 should not touch reptiles or their tanks. Everyone should wash their hands with soap and water after touching an iguana, its food or its tank. Keep reptiles and their equipment out of the kitchen.
Wild iguanas should be left alone. The University of Florida warns that iguanas can bite, scratch with sharp claws and whip with their tails. Never try to grab one.
Iguanas share their habitats with plenty of other wild animals, such as raccoons in Florida. Watching from a distance is the safest way to enjoy them all.
Three things people get wrong
Myth: all iguanas are strict vegetarians. Animal Diversity Web says spiny-tailed iguanas eat many small animals. Even green iguanas sometimes eat insects, snails or eggs, according to the FWC.
Myth: marine iguanas eat fish. Marine iguanas eat seaweed, Animal Diversity Web says. They graze it from rocks or dive for it at high tide.
Myth: lettuce is the perfect iguana food. VCA Animal Hospitals says iceberg lettuce is mostly water. Dark leafy greens, such as collard and mustard greens, are much better.
Did you know? Marine iguanas sneeze out salt. A special gland linked to their nostrils removes the salt they swallow with seaweed.
Try it
Make a food web for a green iguana. Draw what it eats and what might eat it, then add the microbes in its gut that help it digest leaves.
Knowledge check
What do marine iguanas eat?
Show answer
Almost only seaweed, which they graze from rocks or dive for.
Why is iceberg lettuce a poor food for pet iguanas?
Show answer
It is mostly water and has few nutrients.
Frequently asked questions
What do iguanas eat in the wild?
Most wild iguanas eat leaves, flowers and fruit. Marine iguanas eat seaweed, and spiny-tailed iguanas also eat insects and small animals such as rodents and frogs.
What do green iguanas eat?
Green iguanas mostly eat green leafy plants and ripe fruit. Animal Diversity Web says young ones also eat insects and spiders, and adults occasionally eat carrion.
What do marine iguanas eat?
Marine iguanas eat almost nothing but seaweed. Larger ones dive for it at high tide, while smaller ones graze rocks uncovered at low tide.
What should a pet iguana eat?
VCA Animal Hospitals says 80 to 90% of a pet iguana’s diet should be dark leafy greens, with fruit under 20% and insects under 5%.
Can iguanas eat meat?
Some can. Spiny-tailed iguanas eat many small animals. Vets say pet green iguanas need very little animal protein and should never eat dog or cat food.
Are iguanas safe to touch?
Iguanas often carry Salmonella germs. The CDC says children under 5 should not touch reptiles, and everyone should wash their hands afterwards.
Sources
- Animal Diversity Web: green iguana — green iguana diet, digestion and size; its iguana family, marine, desert, spiny-tailed and rhinoceros iguana pages were also used
- Galápagos Conservancy: reptiles — marine and land iguanas, salt glands and El Niño
- Florida Fish and Wildlife Conservation Commission: green iguana — green iguanas in Florida and the 2021 rules; its February 2026 removal news was also used
- University of Florida IFAS: the green iguana in Florida — history, garden plants and safety; the Florida Museum of Natural History’s spiny-tailed iguana study was also used
- VCA Animal Hospitals: feeding iguanas — what pet iguanas should and should not eat
- CDC: reptiles and amphibians — Salmonella and hand-washing
