Adult: Species description based on Savage (2002). A small poison frog (males to 25 mm). Male's throats are green or black; the throat of females is red. Dorsal: Dorsal coloration is variable. Most individuals are red, except for the hind limbs, which are a vibrant bluish-green. Other individuals are yellow or green or red all over; yellow or green individuals with or without some reddish coloration on the arms (Savage 2002). The dorsal skin is granular. Ventral: The ventral surface is generally greenish-blue, with or without black spots.
Breeding season: Breeding occurs during the rainy season (Savage 2002). Males call from vegetation in the forest during the early part of the day and late in the afternoon (Savage 2002). Males and females engage in ritualistic courtship behaviors (Crump 1972). Amplexus occurs with the two individuals joining their vents and facing in opposite directions (Crump 1972). Egg: Females lay 2-4 eggs at a time (Savage 2002). Tadpole: The tadpole is small, with a very long tail with almost no tail fins (Savage 2002).
Habitat: Lowland forest below 100 m. Ecology: Oophaga granulifera is diurnal (Savage 2002). It inhabits leaf litter, but is often found climbing trees and shrubs, or along stream margins (Savage 2002). Call: A harsh series of "chirps" (Myers and Daly 1976, Myers et al 1995). Behavior and communication: Males are territorial, and will engage in wrestling bouts with intruding males if necessary (Crump, 1972, van Wijngaarden and van Gool 1994). Males guard eggs until they hatch, at which time the female returns to transport them to phytotelmata to continue development (Savage 2002). Females deposit unfertilized eggs for tadpoles to consume (Savage 2002). Karyotype: 2N = 20 (Rasotto, Cardellini and Sala 1987) Type locality: on low mountains, north of the Río Diquis, about 3 miles north of Palmar, Puntarenas Province, Costa Rica Diet: The diet consists of numerous types of small arthropods,including ants (Savage 2002).