Poison-Arrow Frogs and Golden Toads

Of all Central America's exotic species none are more colorful than the dendrobatids, or poison-arrow frogs. These are the creatures from which indigenous people have traditionally extracted deadly poisons with which to tip their arrows. Frogs are tasty little prey from the viewpoint of carnivorous amphibians, reptiles, birds, and some mammals (including humans). Hence, in many species, the mucous glands common to all amphibians have evolved to produce a bitter-tasting poison.

In Central and South America at least 20 kinds of frogs have developed this defense still further: Their alkaloid poisons are so toxic that they can paralyze a large bird or small monkey immediately. A few frogs produce poisons powerful enough to kill a jaguar or a human. Several species of dendrobatids that are confined to Costa Rica produce among the most potent toxins known: atelopidtoxin, bufogenin, ufotenidine, and bufotoxin. Pity the poor snake that gobbles up Dendrobatis granuliferus, a tiny bright-green, red, and black frog that inhabits the lowland forests of the Golfo Dulce region. (The frog is commonly seen on forest floors of Corcovado National Park.) Another amphibian, the giant marine toad (Bufo marinus), can squirt its poison in a fine spray, to the sorrow and pain of the many dogs who have tried to eat one of the chicken-sized creatures.

Perhaps the most famous Costa Rican amphibian is the rare golden toad, found only in the Monteverde Cloud Forest Reserve. In fact, the montane rain-forest reserve owes its existence in part to the publicity generated by the discovery of Bufo periglenes. This brilliant, neon orange arboreal toad was discovered in 1964. It is so stunning that one biologist harbored "a suspicion that someone had dipped the examples in enamel paint." The creatures once emerged from the ground by the thousands during mating season. However, only one toad emerged in 1988, and none have been seen since 1989.