Iguanas and Reptiles of Manuel Antonio
Reptiles are everywhere in Manuel Antonio once you slow down: the national park’s management plan records 93 species. The ones visitors notice are the big lizards: the green iguana, the black spiny-tailed iguana (garrobo) sunning near the beach, and the basilisk that can sprint across water. Snakes live here too but are rarely seen. Stay on the trail, watch where you step, and let every reptile be.
Reptiles in Manuel Antonio
Travel Guide › Wildlife › Reptiles and iguanas
According to the park’s 2013–2018 management plan, the 93 reptile species recorded in Manuel Antonio National Park are close to 40% of Costa Rica’s total. Snakes of the colubrid family are the most varied group, with 45 species. The plan also highlights a nocturnal lizard, Lepidophyma reticulatum, as the park’s only reptile endemic to Costa Rica, and notes that small lizards such as anoles help keep insect numbers in check.
Reptiles depend on outside heat to warm up, so mornings are a good time to see lizards basking in sunny spots. This page covers the species visitors see most, then the ones to simply respect from a distance.
Green iguana
Scientific name: Iguana iguana.
Identification
A large lizard that can reach about 2 m from head to tail; most adults weigh 4 to 6 kg. Despite the name, color varies from green to brown and changes with mood, temperature, health and social status. Iguanas are darker in the cool morning, which helps them absorb heat. Young iguanas look more blotchy or banded (Animal Diversity Web). Look for the loose flap of skin under the throat (the dewlap).
Habitat and behavior
Green iguanas are often seen resting on branches, and good basking perches are what they compete for most. In the breeding season males become territorial, bobbing their heads, extending the dewlap and changing color. Females may travel some distance to the same nesting site year after year (Animal Diversity Web). The park’s management plan lists green iguanas in its mangroves and estuaries.
Diet and ecological role
Mostly plants: green leaves and ripe fruit, with the occasional invertebrate. By eating fruit they help disperse seeds, and they are food for larger predators (Animal Diversity Web).
Conservation status
Least Concern on the IUCN Red List (assessed 2022). The park’s management plan also lists it among the park’s reptiles of conservation concern, based on national and international listings.
Black spiny-tailed iguana (garrobo)
Scientific name: Ctenosaura similis. The IUCN calls it the common spiny-tailed iguana; in Costa Rica it is the garrobo, and many visitors call it the “black iguana” or ctenosaur.
Identification
Large and bulky, mostly black or with black bands on a grayish background, often mottled. After basking, the color can lighten and show yellowish or orange markings on the sides. The tail is ringed with rows of sharp, curved spines, which gives the species its name. Males have a clear crest along the back (Animal Diversity Web).
Habitat and behavior
More of a ground-dweller than the green iguana, and able to run on its hind legs. Garrobos live in colonies with a strict pecking order, and males defend territories with head-nodding, “push-ups”, color changes and, if needed, bites and tail-lashing (Animal Diversity Web). In Manuel Antonio they are part of the beach scene: crtrees.org describes garrobos living on the beaches, sometimes on the limbs of the manzanillo tree, and swallowing its fruit whole, even though that fruit is poisonous to people.
Diet
Mostly plants, especially fruit, but adults also take rodents, bats, frogs, small birds and insects. Young garrobos eat mainly insects.
Conservation status
Least Concern on the IUCN Red List (assessed 2015).
Keep your distance: Animal Diversity Web notes that garrobos can bite and wound with their spiny tails when threatened. Never try to pick one up or corner it.
Basilisks: the lizards that run on water
Common basilisk (Basiliscus basiliscus). The park’s reptile list also includes the emerald basilisk (Basiliscus plumifrons).
Identification
A long, slender lizard up to about 80 cm in total, most of it tail. Usually brown or olive (sometimes brighter green) with darker cross bands and cream to yellow stripes along the lip and sides. Males are larger and carry tall, sail-like crests on the head, back and tail (Animal Diversity Web).
Habitat and behavior
Basilisks are active by day and spend their time along streams and waterways, foraging, basking and resting. At night they sleep on perches that can be up to 20 m high. When startled, they rise onto their hind legs and run across the surface of the water, which is why they are nicknamed the “Jesus Christ lizard”. Young, light basilisks can cover 20 m or more this way; larger adults sink after a few meters and swim (Animal Diversity Web).
Diet and ecological role
Omnivores that lean toward animal food: insects and other arthropods, small lizards, snakes, fish, freshwater shrimp and more, with some flowers and fruit. They are predators of many small animals and prey for larger ones.
Conservation status
Common basilisk: Least Concern (IUCN, assessed 2016). Emerald basilisk: Least Concern (IUCN, assessed 2013).
Snakes, crocodiles and sea turtles
Snakes
The park’s management plan lists dozens of snake species, most of them from the colubrid family. It also lists venomous species, including the fer-de-lance (terciopelo, Bothrops asper), the eyelash viper (bocaracá, Bothriechis schlegelii), coral snakes (Micrurus) and the yellow-bellied sea snake. Most visitors never see a snake. Simple habits keep it that way:
- Stay on marked trails. SINAC asks visitors not to leave permitted areas.
- Wear proper closed footwear on forest trails, as SINAC recommends (sandals are not recommended).
- Look before you put your hands on railings, branches or rocks, and before you sit.
- If you see a snake, stop, step back and let it move away. Never try to catch, move or photograph it up close. A guide can point one out safely from a distance.
- If someone is bitten, get medical help immediately.
American crocodile
The management plan records the American crocodile (Crocodylus acutus) and the spectacled caiman in the park’s estuaries and mangroves. The American crocodile is Vulnerable on the IUCN Red List (assessed 2022). Keep well back from the water’s edge in estuaries and river mouths, and never feed them.
Sea turtles
Olive ridley turtles nest mainly on Playa Savegre, in the park’s southern sector, and green and hawksbill turtles have occasionally been recorded nesting there (management plan). If you ever come across a nesting turtle or hatchlings, keep your distance, keep lights off and let them reach the sea on their own.
How to watch reptiles well
- Don’t feed iguanas or garrobos. The park’s management plan lists garrobos, basilisks and green iguanas among the animals involved in conflicts with visitors. Feeding wildlife is prohibited in the park (SINAC).
- Don’t touch or pick them up. SINAC asks visitors not to touch wild animals, and large lizards can bite and scratch.
- Give basking lizards space. Chasing a lizard off its sunny spot costs it warmth and energy.
- No flash, and keep lights low around animals at night.
More on responsible viewing in our wildlife guide.
Where visitors may encounter reptiles
Reptiles are easiest to see when they are warming up, so look in sunny spots in the morning. Nothing here is guaranteed.
- Beaches and beach trees for garrobos, and trees along the shore and rivers for green iguanas. Beaches inside the park are covered in our national park guide; our beach guide covers the rest.
- Streams and wet areas for basilisks.
- Forest trails for anoles and other small lizards, and, with a guide’s help, the occasional snake at a safe distance. ECOTICA‘s concierge can book a guided park walk through our wildlife and nature tours.
Don’t sit under the beach trees without checking what they are: some are manzanillo, a poisonous tree. Our plants and rainforest guide shows how to recognize it.
Sources and further reading
- SINAC – Manuel Antonio National Park (official page, English)
- SINAC – Parque Nacional Manuel Antonio (página oficial: horario, tarifas, servicios, recomendaciones)
- SINAC – Plan General de Manejo, Parque Nacional Manuel Antonio 2013–2018 (PDF; species lists, habitats, visitor impacts)
- Animal Diversity Web (University of Michigan) – Green iguana (Iguana iguana)
- Animal Diversity Web (University of Michigan) – Black spiny-tailed iguana (Ctenosaura similis)
- Animal Diversity Web (University of Michigan) – Common basilisk (Basiliscus basiliscus)
- Trees of Costa Rica’s Pacific Slope (crtrees.org) – Hippomane mancinella (manzanillo)
- IUCN Red List – Iguana iguana: Least Concern (assessed 2022)
- IUCN Red List – Ctenosaura similis: Least Concern (assessed 2015)
- IUCN Red List – Basiliscus basiliscus: Least Concern (assessed 2016)
- IUCN Red List – Basiliscus plumifrons: Least Concern (assessed 2013)
- IUCN Red List – Crocodylus acutus: Vulnerable (assessed 2022)
Last reviewed: September 2026. Conservation categories come from the IUCN Red List assessment shown next to each name; categories can change when species are reassessed. Park rules and opening details belong to SINAC, so check its official page before you go.
