In recent years at Hacienda Barù the Spiny-tailed Iguanas (Ctenosaura similis), sometimes called “Black Iguanas”, have become so used to people that they’ve lost their natural fear and tend to hang out near human dwellings. Having lost their fear doesn’t mean that they are gentle or friendly, only that they don’t run away when you get close. They will still deliver a nasty bite if you try to touch them. A friend once made the mistake of trying to feed one, but the black iguana took a chunk out of his hand along with the piece of cookie being offered. Nine stitches and loads of antibiotics later he told me the story and showed me the ugly, ragged scar.


Spiny-tailed iguanas will eat almost anything. I once saw on sitting on a log with its head near a bright red flower. When a hummingbird came around looking for nectar the black iguana grabbed it and ate it. One of our staff members saw one eat a cane toad. It must have a cast iron stomach to handle the poison in the toad’s skin. Dogs get very sick and sometimes die just from grabbing a toad in their mouthes and then quickly spitting it out. One of our guests snapped a beautiful photo of a large, male, spiny-tailed iguana eating a crab, another example of that high powered digestive system. Twan Leenders, in his wonderful field guide Reptiles of Costa Rica, mentions a report of one Ctenosaura eating a bat. He also mentions reports of adults eating immature individuals of their own species. We haven’t witnessed that at Hacienda Barú, but a staff member once snapped a photo of an adult spiny-tailed iguana eating a juvenile green iguana.


In reality all of these incidents are exceptional cases and don’t represent the normal diet of an adult spiny-tailed iguana. Fruits, leaves, and other vegetable matter make up the bulk of their normal fare. Animal protein treats, like the meals described above, are extras that are readily taken whenever the opportunity presents itself. On the other hand the juveniles do feed mostly on animal protein such as insects and other small arthropods.


During the dry season at Hacienda Barú Lodge Ctenosaura similis often hang out in culverts that go under trails and driveways. Hollows in trees also provide refuge. On bright days they may be observed on the trails around the gardens soaking up sun. One large, adult male we call “Pepe” likes to sun bath on a table near the pool. Two or more can often be found near the marañon (cashew) trees when fruit is falling on the ground. The fleshy part is what they eat. Even their cast iron stomachs can’t handle the highly toxic seed. A fruit called “noni” is another favorite.

Iguana Negra

One or two spiny-tailed iguanas will usually claim the territory near the restaurant and sometimes even walk around the railing near the guests. On rare occasions when they come inside, the restaurant personnel promptly shoo them out. Unseen by the staff, one did sneak into the dining area one bright morning, and made its way to a nearby table where a solo guest was enjoying a leisurely breakfast. The iguana climbed up onto a vacant chair, and from there onto the table where it quickly gobbled up the gentleman’s scrambled eggs. “Oh My God” he exclaimed loudly, totally astounded at the sight of the scaly, spiny, pre-historic-looking lizard stealing his breakfast. After scooting his chair back from the table, he realized that there was no danger and sat with a big smile observing the spectacle. The waitress rushed over with a broom, chased the reptile out of the restaurant, and apologized profusely to the guest. Having recovered from his inicial shock, the man assured her that he had enjoyed the whole spectacle immensely. “Do you charge extra for a show like that?” he laughed. A couple of our guides captured the offending lizard, and took it a long way from the restaurant before releasing it.

And, if all of that isn’t impressive enough, Guinnes Book of World Records says that the spiny-tailed iguana is the world’s fastest lizard, 34.6 kph (21 mph).
You are absolutely guaranteed to see one during your stay at Hacienda Barú Lodge.