Small arboreal hylid (snout–vent length 4 – 7 cm) famous for bulging scarlet eyes bordered by narrow orange eyelids. Dorsum vivid leaf-green; flanks barred electric blue and citrine-yellow; digits webbed and coloured tangerine-orange. Ventrum creamy white. Smooth skin secretes waxy lipid to reduce trans-epidermal water loss. Females larger and deeper-bodied than males. Tadpoles olive-grey with transparent tail fins. Colour pattern concealed while resting: frog tucks limbs, closes eyes, and appears uniformly green; sudden exposure startles predators (flash-colouration).
Yes — females longer/heavier; males have enlarged nuptial pads and produce advertisement “chack” call
Males 4.0–5.5 cm; females 5.5–7.0 cm SVL
Males ≈ 6 g; females ≈ 8 g
5–8 yr wild; up to 10 yr captivity
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≈ 1 yr (males), 1.5 yr (females)
May – October (rainy season)
Clutch of 20 – 50 eggs deposited on underside of leaves overhanging ponds; females may breed twice yr⁻¹
Small arboreal hylid (snout–vent length 4 – 7 cm) famous for bulging scarlet eyes bordered by narrow orange eyelids. Dorsum vivid leaf-green; flanks barred electric blue and citrine-yellow; digits webbed and coloured tangerine-orange. Ventrum creamy white. Smooth skin secretes waxy lipid to reduce trans-epidermal water loss. Females larger and deeper-bodied than males. Tadpoles olive-grey with transparent tail fins. Colour pattern concealed while resting: frog tucks limbs, closes eyes, and appears uniformly green; sudden exposure startles predators (flash-colouration).
Humid lowland and premontane rain forest, forest edges, cacao plantations and riparian corridors from sea level to ≈ 1 250 m; always near temporary or permanent ponds for tadpole development.
Nocturnal insectivore; consumes moths, crickets, flies and small beetles, regulating canopy arthropod populations
Social Structure & Behaviour
Activity pattern: strictly nocturnal; hides on leaf undersides by day.
Calling assemblages: males call from vegetation 0.5 – 3 m above ponds; chorus size 3 – 15.
Territoriality: males defend small leaf territories with “quivering” displays and grappling.
Reproductive behaviour: amplectant pairs lay gelatinous egg masses on palm or Heliconia leaves; male fertilises externally.
Anti-predator tactics: flash coloration and startle jumps; embryos hatch early when sensing vibrational cues.
Embryos hatch prematurely when attacked by egg-eating snakes (Leptodeira).
Exhibits “cryptic colour sleep”—at rest, pupils narrow and body appears uniform green.
Popular conservation icon; featured on Costa-Rican postage stamps (2004 series).
Can leap over 45 cm—more than 8 × body length—to escape predators.
Spectral sensitivity peaks at 530 nm, aiding nocturnal colour vision.
