Costa Rican Wildlife – Part 2
This post will focus on some of the reptile, amphibian, and bird life that I encountered on the Osa Peninsula.
I encourage you to click on the images in this post to enlarge them for a better, more detailed viewing experience.
Although we saw reptiles, amphibians and birds everywhere we visited, the places we targeted for these groups on the Osa were Carate, La Tarde (Corcovado National Park), and a cruise on the Sierpe River that flows through the Terraba-Sierpe Wetlands, home to a lush, mangrove ecosystem.
For the Corcovado area, local spotters went into the dense forest to collect species that are difficult to spot so our group was not trampling the area looking for small animals. All species were returned to their environment, unharmed, after we had viewed them.
Reptiles
The Brown Spiny Lizard is a medium-sized lizard about 6- to 7-inches long with spine-tipped scales. They have a pair of light colored stripes that run from behind the eye to the base of the tail. They are found in open areas such as roadsides, beaches, and fields in dry locations. Although quite common, I could not resist this colorful photo.
The Helmeted Iguana is another medium-sized lizard that can be 14-inches long from tip of face to tip of tail. They are notable for their prominent helmet-like crest that transitions into a low, sawtooth ridge on the back. Being found in humid forests, they are arboreal and sit motionlessly on vertical branches and trunks waiting for a suitable meal to wander by. They are a patient sit-and-wait-predator and are very difficult to spot because they are so well camouflaged.
The Green Iguana is the largest of the lizards that are found in Costa Rica. They can grow to be 79-inches long!
They have comb-like spines that run from the back of the head to the tail and a large circular scale below the ear. When the sun is shining, these lizards will climb onto exposed branches that overhang water to bask and will dive into the water if they need to escape danger. The adults are mostly vegetarians and have microorganisms in their digestive tract to digest the plant matter.
The Striped Basilisk is a fairly large lizard up to about 20-inches long. They have distinctive head crests and a white to yellow colored stripe on the face and side.
They are best known for how they “walk” on water. When they feel the need to escape, they do so by running across the water’s surface!
Basilisks have well-developed fringes on the sides of their hind toes which stay folded until the lizard needs to run across the water. Opening these fringes increases the area of each foot. When the feet press down on the water, surface tension holds up the lizard. The smaller the lizard, the farther it can run on top of the water. These lizards also swim.
Meso-American Sliders are medium-sized turtles and are the largest of the fifteen subspecies of the Common Slider.
They inhabit large rivers, ponds, canals and marshes in areas that maintain fresh water year-round with an abundance of vegetation. These turtles tend to congregate in groups to sun themselves. They are omnivores eating fish, frogs, water snakes, snails, and aquatic vegetation. They can live up to 30 years in the wild. It is illegal to keep these turtles as pets in Costa Rica.
The Eyelash Pitviper gets it’s name from spine-like scales over their eyes which look a bit like eyelashes. They are one of the smallest of the venomous snakes in Central America growing to only 2.5 feet long.
They range from southern Mexico, through Central America, and south to Venezuela. These snakes are responsible for a large percentage of the snake bites that occur in Costa Rica despite not being very aggressive. Their venom is potent and can be deadly. They are arboreal, often found on the upper surfaces of branches. The adults tend to feed on birds and small mammals that are found in the treetops. Eyelash pitvipers can be yellow, green or pinkish in color depending on the habitat in which they live. You might think you would have no problem seeing one of these bright yellow snakes, but they are often found in banana trees where the yellow color serves as camouflage! In fact, these snakes have inadvertently been sent throughout the world in banana shipments.
While I love lizards, I do not care for snakes so it took me a while to decide to photograph this one. This specimen was a captive snake that was brought out for us to photograph. It did not feel threatened and was not hungry. Nonetheless, I kept my distance and photographed it with a telephoto lens. My macro lens would have captured the eyelash detail better, but I was not going there!
At the dock area where we boarded our boat to cruise up the Sierpe River, this was a prominently displayed sign. We were soon to see why…
American Crocodiles are semi-aquatic reptiles that can grow up to a length of 24-feet although they are usually more in the range of 13-feet. They are common residents of the Costa Rican lowland rivers, swamps, lagoons and estuaries.
Crocodiles and alligators, while both belonging to the order Crocodylia, are very different. Crocs are able to tolerate saltwater due to specialized glands that filter out salt. Although alligators also have these glands, they have evolved to being nonfunctional, thus, they can only live in freshwater. Another trait that separates crocodiles from alligators is their much higher level of aggression. We saw many crocodiles on our Sierpe cruise so the warning on the sign at the dock was prudent as no one wants crocodiles to learn food comes from boats!
Crocs are often seen basking in the sun on the shore or on sandbars, laying motionless for hours at a time. As reptiles, they have no thermo-regulation system. When they get too hot, they will either go into the water or open their mouths to cool off. The crocodile in this photo above was not smiling at us but rather cooling off. Crocs are excellent swimmers and are able to stay submerged for an hour or more. They feed on a variety of aquatic animals including crabs, amphibians and fish. They sometimes eat waterfowl or small mammals and will occasionally attack humans.
A crocodile will deposit 20-60 eggs in a shallow nest that has been dug near the water. These eggs are incubated by the heat generated from vegetation decomposing around the nest cavity. Interestingly, the sex of the offspring is determined by the incubation temperature. Crocodiles have no natural enemies other than humans.
Amphibians
Frogs were the types of amphibians that we encountered on the Osa Peninsula.
The Red-eyed Tree Frog was my favorite of the frogs. They are a nocturnal, arboreal species that spends the majority of their lives in the forest canopy. They sleep on the underside of leaves during the day and hunt for insects at night.
They have “sticky fingers” that allow them to adhere to vegetation, and their big red eyes allow them to see well in the dark. Although they are brightly colored, they are not poisonous. We saw a number of these during nocturnal walks at Crocodile Bay.
The Masked Tree Frog is a common nocturnal Costa Rican frog. It is identifiable by a Zorro-like mask on its face that provides camouflage by hiding the shape of the eyes offering protection from their predators who look for open eyes when hunting. The markings of the mask start at the nose and go back along the face toward the ear, covering the eyes so they do not look open. Unfortunately, you can only see a hint of the mask in this photo.
This species has the ability to change color from light tan through olive green to match the color of its surroundings providing more camouflage. These frogs are not poisonous. When breeding, the males float on the surface of a pool or puddle by blowing up two bubble-like sacs on their throats and emitting a very loud call. Using the beam of a flashlight, we were able to spot several of these floating in a water feature at Crocodile Bay. We had been attracted to them by their loud calling.
The Granular Poison Frog is a tiny frog that is only about 0.8-inches long and lives in the litter of the forest floor. It has granulated skin with a bright orange head, body and upper arms. It’s underside, legs and lower arms are bluish-green in color.
These frogs make no attempt to camouflage themselves from predators. The bright color pattern sends the message – “Do not touch, I’m poisonous”. These frogs secrete potent toxins onto their skin that have been used for hunting by some native peoples earning them the generic name poison dart frogs. When a blow dart coated with the poison strikes a prey animal, the toxin is directly administered to the bloodstream. Monkeys and other small animals have been observed to drop dead in a minute or less after being struck. Although these frogs are pretty harmless to humans unless ingested, we were careful to wash our hands if we touched them and certain did not kiss any of them!
The Golfodulcean Poison Frog is another small terrestrial frog that is about 1-inch in length and also secretes toxins onto its skin.
They have blue-green body coloration with gold, orange or red stripes from the head down the back. They are an endangered species found only in the Golfo Dulce region.
Birds
The Yellow-throated Toucan is a fairly large bird at 20- to 24-inches long, weighing about 1.5 pounds, and having a very large 6- to 8-inch beak.
They are primarily fruit eaters but will feed animal matter to their nestlings. These birds forage primarily in the forest canopy, often singly or in pairs. They nest in tree cavities resulting from rot and lay two to three eggs. This species is listed as near threatened due to continuing conversion of its forest habitat to agriculture.
The Scarlet Macaw is a large, colorful parrot of Central and South America. In some areas, this species has suffered local extinction due to the effects of habitat destruction or capture for sale in the pet trade.
These birds are large at about 32-inches in length (half of that length is the tail) and weigh over 2-pounds. They emit loud squawks and screams that are designed to carry over miles to communicate with other members of their group. In the wild, these birds have 40- to 50-year lifespans which can increase to 75-years or more in captivity. Typically, they feed on fruits, nuts, seeds, flowers, nectar, insects and larvae. In Costa Rica, macaws particularly like to eat the fruits of the non-native, introduced Almond Beach tree. This is what the bird in the photo above is eating. Many of these almond trees have been planted along the coastal beaches and have helped to increase the scarlet macaw population dramatically.
The Red-Lored Amazon is a 13- to 14-inch long parrot found primarily on the eastern coast of Mexico, throughout Central America, into very northern South America. They are vegetarians eating fruits, nuts and seeds.
Unfortunately, in some areas outside Costa Rica, the red-lored amazon has become endangered due to their capturing for the pet market. These birds are long-lived with lifespans up to 80 years. They are loud which can be a problem in a pet environment and sometimes use their strong beaks to inflict painful bites.
The Yellow-headed Caracara is a bird of prey in the falcon family. They are found in lightly-treed, open landscapes such as areas with palms or scattered trees, and pasture margins.
They are omnivores that also rely greatly on carrion scavenging. Caracaras forage for insects, amphibians, invertebrates, and small rodents; eat the fruits of oil palms, coconuts and seeds; and are known to pick ticks off cattle and other animals.
The Lineated Woodpecker is a large woodpecker that ranges from Mexico south to northern Argentina. This species is 12- to 14-inches long and very reminiscent of the pileated woodpecker found in the U.S.
Like other woodpeckers, they drill into trees after insects. Ants are a particularly favorite food.
The Spectacled Owl is a large owl that lives solitarily in dense stands of the tropical rainforest. It is noted for its prominent facial markings and large yellow eyes. During the day this owl hides in the forest canopy coming out at night to hunt and returning to the canopy before dawn. They eat invertebrates, small rodents, bats and even small monkeys.
The Boat-billed Heron is a nocturnal heron of mangroves and freshwater marshes in the tropical lowlands. During the day, they roost in trees and come out at night to feed along the edge of lakes, ponds and rivers.
Their foraging behavior is similar to other herons, and they feed on small fish, crabs, insects, small mammals and amphibians.
The Purple Gallinule or swamphen is a medium-sized marsh bird with long legs and toes. Those long toes spread the bird’s weight out allowing it to walk along on top of floating aquatic vegetation.
They are omnivores eating a wide variety of plant and animal matter.
The Little Blue Heron is about 2-feet tall and weighing 14-ounces. Adults of both sexes have blue bodies with purple heads, a blue beak with dark tip, and green legs.
Juveniles of this species are white making them look like snowy egrets, however, they have a two-toned bill similar to adults rather than the orange bill of an egret. These herons eat fish, crabs and other small animals.
The Green Kingfisher ranges from Texas, through Central America, and south to central Argentina. They are small birds of about 7-inches in length weighing in at 1.5-ounces.
They tend perch close to the water surface in dark areas along waterways where they watch for a tasty morsel to wander by. Their dinner of choice is fish, but they will also eat insects and frogs. These birds are very spooky and are a difficult species to photograph.
Here are a few more miscellaneous photos for your enjoyment. Click on each of them to see the entire photograph.
My trip to Costa Rica was an awesome one. If you have an interest in photographing wildlife, I recommend you check out Juan Pons’ Photo Workshops. I have yet to be disappointed in any wildlife-seeking adventure I have taken with him. The Osa Peninsula was a great place to see some interesting, and even unique, wildlife. A previous post, Costa Rican Wildlife- Part 1. Land of Sloths and Monkeys, covers the mammals I photographed on my trip. My final post in this series will cover the wonderful birds of the Costa Rican cloud forest that I photographed. Stay tuned for Part 3!
Resources:
- Reid, Leenders, Zook & Dean, The Wildlife of Costa Rica, A Field Guide
- Garrigues & Dean, The Birds of Costa Rica, A Field Guide
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