Red-Eyed Tree Frog (Agalychnis callidryas)
Order Anura, Family Hylidae, Genus Agalychnis, Species Agalychnis callidryas
Species
Red-Eyed Tree Frog (Agalychnis callidryas)
Family
Order Anura, Family Hylidae, Genus Agalychnis, Species Agalychnis callidryas
Size
Adult snout-to-vent length (SVL) exhibits sexual dimorphism: females are larger, measuring 50 to 71 mm, while males are smaller, measuring 38 to 56 mm. Weight ranges generally from 5 to 15 grams. Tadpoles measure about 40 to 45 mm just before metamorphosis.
Conservation
Listed as Least Concern on the IUCN Red List due to its wide distribution and large, stable populations. However, local populations face threats from habitat loss via deforestation, climate change, and the deadly amphibian chytrid fungus.
Description
The Red-Eyed Tree Frog is an iconic symbol of the Central American rainforest. With its neon green skin, electric blue-and-yellow flanks, and startlingly large ruby-red eyes, it is one of the most visually stunning amphibians on Earth. Spending its daylight hours camouflaged beneath broad leaves, it transforms into an active hunter of the night canopy, leaping expertly between branches.
Key Features
Brilliant red eyes with vertical pupils, vivid green dorsal skin, blue-and-yellow vertical stripes on the flanks, and bright orange-red toe pads.
Physical Description
The Red-Eyed Tree Frog has a slender, streamlined body adapted for an arboreal lifestyle. Its head is broad with large, striking vertical-pupiled red eyes that provide exceptional nocturnal vision. The limbs are long and slender with large, sticky toe pads for clinging to leaves and vertical surfaces. There is no webbing on the hands, but moderate webbing on the feet. The tympanum is distinct, and the overall body proportions emphasize agility and leaping ability among rainforest foliage.
Skin Texture & Coloration
The dorsal skin is smooth and bright green, though it can darken to olive or brown depending on mood, light, and temperature. The flanks are vibrant royal blue or purple with vertical yellow or white bars. The belly is soft and white to cream-colored. The toe pads are bright orange or red, creating a striking aposematic flash of color when startled. Mucus production keeps the skin moist and sticky for adherence.
Distinguishing Features
Diagnostic field marks include the brilliant red eyes with vertical pupils, bright orange-to-red toe pads, neon green dorsum, and blue-and-yellow striped flanks. No other co-occurring rainforest frog combines this exact pattern of eye color, limb coloration, and lateral striping.
Habitat
Inhabits lowland tropical rainforests, humid tropical lowlands, and pre-montane forests, typically near permanent or semi-permanent bodies of water such as ponds, swamps, and sluggish streams. They are strictly arboreal, spending most of their lives high up in the forest canopy on the undersides of broad leaves.
Geographic Range
Native to the Neotropics, ranging from southern Mexico through Central America (Belize, Honduras, Guatemala, Nicaragua, Costa Rica, and Panama) down to northwestern Colombia.
Behavior
Strictly nocturnal and arboreal. During the day, they practice passive defense by sleeping motionless on leaf undersides, drawing their bright limbs tightly against their bodies and closing their eyes to hide their red coloration, showing only green skin. Locomotion is primarily by climbing and powerful leaping.
Diet & Feeding
Carnivorous ambush predators. Their diet consists primarily of nocturnal insects including moths, crickets, flies, grasshoppers, and smaller frogs or beetles. They use a sit-and-wait hunting strategy, lunging forward and capturing prey with a sticky tongue.
Reproduction
Explosive breeders triggered by heavy rains at the start of the wet season. Males call from vegetation overhanging water. Following axillary amplexus, females deposit gelatinous clutches of 30 to 100 eggs on the undersides of leaves directly above water bodies. When the eggs hatch, the tadpoles drop directly down into the water below.
Vocalizations
The advertisement call is a soft, low-pitched 'chack' or 'chunk' repeated at irregular intervals. Males also produce a 'tuck-tuck' sound during territorial disputes. Choruses can be moderately loud when many males gather near breeding sites after heavy rains.
Life Cycle
Eggs develop on leaves for about 6 to 8 days before hatching into aquatic tadpoles. The larval stage lasts roughly 3 to 10 weeks depending on water temperature and food availability. Metamorphosis produces tiny juvenile froglets that climb into low vegetation. Sexual maturity is reached around 1 year of age. Total lifespan is typically 3 to 5 years in the wild.
Conservation Status
Listed as Least Concern on the IUCN Red List due to its wide distribution and large, stable populations. However, local populations face threats from habitat loss via deforestation, climate change, and the deadly amphibian chytrid fungus.
Toxicity & Defense
Non-toxic and lacking potent chemical defenses. They rely primarily on behavioral camouflage during the day and startle-coloration (deimatic display) at night—flashing their bright red eyes and colorful flanks to confuse or deter potential predators.
Ecological Role
Acts as an important predator of canopy insects, helping regulate invertebrate populations. Serves as a vital prey item for snakes, bats, birds, and tarantulas, and functions as an environmental health indicator for tropical forest ecosystems.
Similar Species
Other leaf frogs in the family Hylidae, such as the Gliding Leaf Frog (Agalychnis spurrelli), which has smaller eyes and different flank patterns, and various species of genus Boana or Cruziohyla, which lack the iconic red eye and bright flank striping combination.
Observation Tips
Best observed at night during the rainy season using a flashlight or headlamp near bodies of water in Costa Rica, Panama, or other Central American regions. Listen for their characteristic 'chack' calls echoing from overhanging branches.
Handling & Safety
Handling should be strictly minimized as human skin oils, salts, and chemical residues (like insect repellent or sunscreen) can easily harm their sensitive skin. They are entirely non-toxic to humans, but care should be taken to avoid injuring their delicate bodies.
Seasonal Activity
Active year-round in tropical habitats, but drastically more active and vocal during the wet season (May to December) when breeding takes place. During prolonged dry spells, they may reduce activity and seek out humid refuge sites.
Cultural Significance
An iconic poster child for rainforest conservation, biodiversity, and eco-tourism. Its striking visage frequently appears on travel guides, documentaries, conservation campaign logos, and Costa Rican souvenirs.
Interesting Facts
Despite their bright coloration which seems counterintuitive for camouflage, their daytime resting posture hides all bright colors, leaving only green visible. Their embryos can detect vibrations from predatory wasps or snakes and hatch prematurely to drop into the water and escape.