Monday, August 15, 2011

Costa Rica – Poison-dart frog

This spectacular little frog is the Granular Poison-dart Frog (Dendrobates granuliferus). Deanna found this gem on a rainforest trail during our nightly invertebrate collection walks.

Although this individual turned up at night, this species is primarily diurnal. The buzzing calls of the males can be heard from dawn until mid-morning.  They will also call late in the afternoon but fall silent when the bulk of the frogs here begin their activity after dark.

These frogs have potent toxins within their skin, an obvious strategy to avoid predation. Their common name is derived from its use by native hunters; they would extract the toxins and cover the tips of their darts, thus killing prey quickly with a small projectile. The species with the most potent toxin occurs in Columbia, where this practice was common.

Dendrobates granuliferus lays it eggs on the forest floor. After the tadpoles emerge, the adults carry them individually up into the trees and deposit them into small bodies of water, such as that held in bromeliads. 


  1. Hi Alan
    What great shots. Wonderful. you'll have to do a book on your expoits in the Osa.

  2. Thanks David - I was thinking I might put together a iphoto book as a record of the trip.