Red-Eyed Tree Frog (Agalychnis callidryas)

Order: Anura; Family: Phyllomedusidae (Leaf Frogs); Genus: Agalychnis; Species: A. callidryas. Formerly classified under Hylidae, they are distinguished by vertical pupils and specialized arboreal spawning habits.

Species

Family

Size

Exhibits sexual dimorphism; females are larger, reaching 70–77 mm (2.7–3.0 in), while males average 50–59 mm (2.0–2.3 in) in snout-to-vent length (SVL). Weight typically ranges from 6 to 15 grams.

Conservation

IUCN Status: Least Concern. The population trend is considered stable, though they face local risks from habitat loss (deforestation), chemical pollution, and the chytrid fungus (Bd).

Description

The Red-Eyed Tree Frog is the 'poster child' of the tropical rainforest. When sleeping on a leaf, it is a master of disguise, appearing as a simple green bump. However, at night, it transforms into a kaleidoscopic marvel. Its oversized red eyes and neon-orange feet are among the most photographed features in all of herpetology, serving as a vibrant reminder of biodiversity.

Key Features

1. Large bright red eyes with vertical pupils; 2. Blue or purple vertical bars on yellow flanks; 3. Bright orange or yellow toe pads; 4. Bright green dorsal skin.

Physical Description

A slender-bodied arboreal frog with a distinctively narrow waist. It features large, bulging eyes with vertical pupils, a short snout, and long, thin limbs. The feet possess highly developed adhesive suction discs on the tips of the toes and fingers, with moderate webbing on the hind feet.

Skin Texture & Coloration

Skin is smooth and dorsally leaf-green. The flanks (sides) are strikingly marked with vertical creamy-yellow and blue or purple bars. The belly is white or cream. The most iconic feature is the brilliant red iris of the eyes. Thighs and upper arms often show hidden flashes of blue, while the hands and feet are bright orange or yellow.

Distinguishing Features

The combination of scarlet-red eyes with vertical slit pupils, neon orange feet, and blue-and-yellow striped flanks is diagnostic. No other frog in its range possesses this exact tri-color combination (Green, Red, Blue/Yellow).

Habitat

Primary and secondary tropical lowland rainforests. They are strictly arboreal, living in the canopy near water sources such as ponds, slow-moving streams, and ephemeral pools. Found at elevations from sea level to roughly 1,250 meters.

Geographic Range

Native to the Neotropics, ranging from southern Mexico through Central America (Guatemala, Belize, Honduras, Nicaragua, Costa Rica, Panama) to northwestern Colombia.

Behavior

Nocturnal and arboreal. During the day, they tuck their bright limbs under their bodies and close their eyes to blend in with green leaves ('camouflage'). If startled, they pop open their eyes and reveal their bright flanks—a 'startle display' meant to confuse predators. They move by climbing more than hopping.

Diet & Feeding

Carnivorous as adults. They are sit-and-wait predators that consume moths, crickets, flies, beetles, and other small invertebrates. They use a sticky, retractable tongue to capture prey at night.

Reproduction

Breeding occurs during the rainy season. Males call from vegetation overhanging water. The female carries the male on her back (axillary amplexus) to a leaf above a pond, where she deposits a gelatinous clutch of 30-50 eggs. The tadpoles hatch and drop directly into the water below.

Vocalizations

The advertisement call is a loud, percussive 'chack' or 'chuckle,' often doubled as 'chack-chack.' It is a low-frequency sound compared to other hylids. Males also produce a 'vibration' or 'shaking' territorial display during chorusing.

Life Cycle

Eggs hatch in 6–10 days. Tadpoles can hatch prematurely if they sense vibrations from a predator (like a snake). The tadpole stage lasts 1–3 months in water before metamorphosing into froglets. Sexual maturity is reached in 1–2 years. Total lifespan is approximately 5 years in the wild.

Conservation Status

IUCN Status: Least Concern. The population trend is considered stable, though they face local risks from habitat loss (deforestation), chemical pollution, and the chytrid fungus (Bd).

Toxicity & Defense

Not toxic to humans. They lack the potent alkaloids of poison dart frogs. Their primary defense is 'startle coloration' (aposematism/flash colors) to momentarily surprise a predator, followed by rapid escape or camouflage.

Ecological Role

Serves as an important secondary consumer, controlling insect populations. They are a critical food source for bats, snakes, and birds. They also serve as an indicator species for environmental humidity and water quality.

Similar Species

Agalychnis annae (Blue-sided Tree Frog) has yellow/orange eyes but lacks the red; Agalychnis spurrelli (Gliding Leaf Frog) has darker eyes and extensive webbing for gliding.

Observation Tips

Best found during the rainy season at night near forest ponds. Use a flashlight to look for the 'eyeshine' (the red reflection) in trees 1 to 3 meters above the water. They are most active during or immediately after heavy rain.

Handling & Safety

Handling should be minimal. Amphibian skin is highly semi-permeable; toxins from human hands (sunscreen, oils, soap) can harm them. If necessary, use wet hands or nitrile gloves. They are harmless to humans but may jump suddenly.

Seasonal Activity

Maximum activity occurs during the wet season (typically May to November in much of their range) for breeding. During the dry season, they remain high in the canopy or deep in bromeliads to conserve moisture.

Cultural Significance

An international icon for rainforest conservation and ecotourism, especially in Costa Rica. It appears on more environmental posters, stamps, and logos than almost any other amphibian.

Interesting Facts

The embryos can hatch in seconds if they feel the vibrations of a predatory cat-eyed snake (Leptodeira), a phenomenon known as 'environmentally cued hatching.' They are one of the few frogs that use 'social vibration' to communicate dominance.

Identified on 3/30/2026