PATERNITY AND PATERNALISM

No vertebrate order exhibits a wider range of reproductive strategies than do the frogs. Like all amphibians, their eggs have no shells and are vulnerable to desiccation. In open water that is not a problem, but there they are subject to predation by fish and other animals. It is the tension between these two dangers that has led frogs down so many different reproductive paths. There are frogs that lay their eggs in burrows, on land, on leaves, in foam nests, and in every imaginable kind of water vessel. Members of several families carry their eggs on their own backs in several different ways—in fact parental care is widespread and varied among frogs. The females of the two species of the Australian genus Rheobatrachus, which probably went extinct in the 1980s, actually brooded their eggs in their own stomachs. Parental care has probably been best documented among the Neotropical poison frogs of the family Dendrobatidae. A small number of eggs are typically laid on a leaf on the forest floor, where they are guarded by one or both adults, who urinate on them periodically to keep them moist. Upon hatching the tadpoles are taxied to water on the back of an adult. Probably the best known member of this family is the Strawberry Poison Frog (Dendrobates pumilio) of Central America's moist Caribbean lowlands. Within their range these aptly named ½-inch long amphibians are extremely common, and their life history has been documented time and again in the literature for well over a century. The male guards the eggs, and the newly-hatched tadpoles are transported, one at a time, to the tanks of a pre-selected bromeliad, where they are deposited. The female returns regularly to lay an infertile egg in each tank, for the tadpoles to feed upon. The original accounts described the male carrying the tadpoles to the bromeliad, and for many decades naturalists (myself included) simply took the older literature at its word, and credited Papa Frog for the effort. The fact that the she-frogs had been doing the actual hauling went unnoticed until the 1980s. The sexual dimorphism of this species is far from obvious, but the males can be distinguished from the females by their slightly smaller size and beefier first two fingers. Most of what we know about the world we know from being told. If we questioned it all, we'd have time for nothing else. Still, having an open pair of eyeballs can be very rewarding.
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ASCENSIÓN—STRAWBERRY POISON FROG & TADPOLE (2005) acrylic 40" x 15"