Iguana iguana) are found sleeping.
The first species of snake I discovered in Costa Rica was Sibon longifrenis:
I'll always be fond of this species for being my first Central American snake. Little is known about it's natural history.
Imantodes inornatus was my second most encountered snake. These nocturnal predators can be founding chowing down on frogs, anoles, or amphibian eggs.
Another I. inornatus.
Leptodeira annulata is another common denizen of the swamp, preying nocturnally on frogs. Although this snake does not possess large, hinged solenoglyphous fangs like a viper, it has rear teeth that are grooved and linked to venom-producing Duvernoy's glands. If this snake is allowed to chew on a human hand, the venom can elicit a reaction.
While searching around the swamps, I did discover one anole species.
The aquatic anole (Norops oxylophus). I found this species active both diurnally and nocturnally in swamps and streams. The males of this species have a solid orange dewlap.
Characteristic dewlap of male N. oxylophus.
White-lipped mud turtle (Kinosternon leucostomum). Like other members of the genus Kinosternon, the domed shell of this species probably helps protect against crocodylian predators. These guys are omnivores that eat pretty much anything.
Most people have seen snapping turtles before in the United States (Chelydra serpentina). One afternoon, while wading through a swamp in search of the resident caiman, I heard a loud splash nearby. Thinking I found my quarry, I was startled to see a spiked turtle carapace swimming my way. I quickly scooped it up and carried it to the shore for pictures.
Recent research has separated the Costa Rican snapping turtle into a new species (Chelydra acutirostris). In particular, I noticed that this snapper had two tentacles projecting from its chin. Presumably, these are sensory organs called barbels. The disposition of this individual was especially nasty.
Rhinoclemmys funerea. This large species can be found basking on logs in swamps or walking around the forest. The carapace above was 10 inches long.
Spectacled caimen (Caimen crocodylus). I found these guys active nocturnally. Occasionally, I heard the juveniles calling to the adults, which was pretty cool. One of my main regrets is never getting one of these guys in hand....
Most of the above descriptions are based off my personal experiences. However, I often consult with the bible of Costa Rican herpetology, "The Reptiles and Amphibians of Costa Rica" by Jay M. Savage, University of Chicago Press (2002).