Middle American Rattlesnake (Crotalos simus)

The Middle American Rattlesnake is a large, venomous snake. It has a drab color pattern, consisting of dark diamond-shaped blotches on a light brown base coloration. The key differentiator with all other venomous species in Costa Rica is the rattle, which produces a loud, menacing sound when it is vibrated rapidly. Indeed this sound causes fear in most people, as it is associated with the killer nature of these animals. Rattlesnakes however use this sound more as a defensive strategy, trying to scare off potential predators. As long as one is careful not to approach this snake more than it allows, it should be safe to watch them on their habitat.

Side-striped Palm-Pitviper (Bothriechis lateralis)

The Side-striped Palm-Pitviper is a venomous snake, sharing its genus with the Eyelash Palm-Pitviper. The Side-striped is green, which helps to camouflage them in the rain forest, as it mainly has arboreal habits. It has a prehensile tail, which means that it can be coiled around branches that work as an anchor to keep its balance. It is moderate in size, less than 1 meter in length, typically between 60 and 70 centimeters. It has a light-blue postocular stripe. Juveniles are rather drab, having a brown skin.

Annulated Tree Boa (Corallus annulatus)

The Annulated Tree Boa is a large arboreal species that inhabits the Caribbean side of Costa Rica. Unlike other Boa species like the Mesoamerican, one morph of this species are brownish-red in color, which renders them rather conspicuous against the dark green background in the tropical rain forest. Their nocturnal habits and preference for staying high in the trees make them difficult to spot. The color pattern consists of a series of diamond-shaped blotches, which are darker over the dorsum and lighter towards the venter. Some individuals have a cream base color instead of the brownish-red of the specimen shown below.

Green Iguana (Iguana iguana)

Green Iguanas are the biggest species of lizards in the world, reaching lengths up to 1.5 meters including the tail. They are abundant in Costa Rican lowlands, and can be found in most of America’s continent, either naturally occurring or as established populations of escaped pets, as they are a very frequent target among pet lovers. They can be found in many beaches, around rivers, high in the tree canopy or walking slowly on the grass. Their diet is composed mostly of leaves, flowers and fruits, although some individuals have been observed eating insects and rodents.

Green Iguanas are not necessarily green in color, instead they have a lot of variability in their range. In some areas they are green, others brown or red, even blue in Peru. The back of the male is covered with spines, a defense mechanism to keep predators at bay, and they feature a dewlap, which is a fold of skin that starts at the front of the lower jaw and ends at the junction where the front limbs start. The dewlap is normally hanging, although it can be displayed as a sign of aggression.

Pug-nosed Anole (Anolis capito)

The Pug-nosed Anole is a small, slender lizard with a green body and a conspicuous black line that runs from the lower jaw through the eye and to the top of the head. The iris is orange with a black, round pupil. They are active during the day and sleep during the night. The individual below was seen in Yorkin near the frontier with Panama, where it stayed motionless for more than half an hour, while we illuminated it with lamps and took pictures from close distances.

Spectacled Caiman (Caiman crocodilus)

Caimans are easy to confuse with crocodiles, however both belong to different families in the Taxonomic hierarchy. While each species in both families has its specific characteristics, there are a few physical traits that differentiate species from each family:

  • Jaws: The Crocodile has a V-shape, while the Caiman and Alligator have a U-shape. This can be seen most notably from above or the front, not so easily from the side.
  • Teeth: In Caimans, due to the way the teeth are placed, the lower jaw’s teeth are not visible when the mouth is closed. Crocodiles do show both upper and lower teeth at all times.

The Spectacled Caiman in particular has become established and common in Costa Rica. Like most reptiles, being cold blooded, they bask in the sun during the morning to warm up their bodies, before going for a day’s hunt. During that time, they may lie motionless in almost any place, like fallen trees, beaches and riversides. Adults have a length between 1.4 and 2.5 meters.

Green Basilisk (Basiliscus plumifrons)

The Green Basilisk, also known as the Jesus Christ Basilisk due to its incredible feat to run on water, is one of the four species of the Basiliscus genus and of three species to occur in Costa Rica. The similar Striped Basilisk is brown with two yellow lines that run one through they, and a thicker one from below the eye, both ending in the upper portions of the back.

The male has a big crest that protudes both on the head, back and tail, which can be raised to signal that it is angry or defending its territory. Most of its body is green with light blue spots around the back, a color pattern that lets it camouflage very easily in foliage and vegetation, particularly during the morning when they bask in the sun to warm up their bodies. The female shows a lighter shade of green than the male. Their eyes are bright yellow. Both their fingers and toes are very large, with scales that can be extended, increasing the effective surface area of their feet and enabling them to run over water for short distances, up to 20 meters.

Striped Basilisk (Basiliscus vittatus)

The Common Basilisk, also known as the Jesus Christ Basilisk due to its incredible feat to run on water, is one of the four species of the Basiliscus genus and of three species to occur in Costa Rica. The similar Green Basilisk is (obviously) green, and the male has a big crest that protudes both on the head, back and tail, while the Striped Basilisk only has a crest on the head and a small ridge on the back.

It is brown with two yellow lines that run one through the eye, and a thicker one from below the eye, both ending in the upper portions of the back; this color pattern lets it camouflage very easily, particularly during the morning when they bask in the sun to warm up their bodies. Both their fingers and toes are very large, with scales that can be extended, increasing the effective surface area of their feet and enabling them to run over water for short distances, up to 20 meters.

Red Coffee Snake (Ninia sebae)

Red Coffee Snake is a non-venomous species of snakes, however most of the body is red, which warns potential predators not to come close. People ask me if this is a Coral or False Coral when they see the pictures, but it only bears a small resemblance. It lacks any ring patterns and is very slim, two traits that can help in identification. Its forehead is black, and it has a black mark on the back as well, just before the red body skin starts. With its elongated and thin body, one might think it is just a worm. It is found in Mexico and Central America.

Picado’s Jumping Pitviper (Atropoides picadoi)

The Jumping Pit Viper is another feared venomous snakes that occurs naturally in Costa Rica. They have a skin pattern similar to the Fer-de-lance, hence they might be confused on the field. Since both are dangerous, it is still a safe bet to stay away, whether the individual is one species or the other. The Fer-de-lance can be distinguished by the smaller head and ligher eyes; also the Jumping Pit Viper has solid brown triangles all along the body, while the Fer-de-lance features brown markings that are connected diagonally, but on the inside hey have lighter colors.

In spite of its common name, it is not more common for the Picado’s Jumping Pitviper to jump on top of their prey than any other viper species. Its Spanish common name also refers to a “Eye of Round” beef cut, not exactly helpful if someone shouts “Mano de Piedra!”. Their venom is very strong, so people are very cautious if they handle them.