Dyeing Poison Frog

The name comes from a long-repeated claim that Indigenous people of the Guianas used the frog's skin secretions to change the colour of parrot feathers — plucking a young green feather, rubbing the wound with frog toxin, and having the feather regrow yellow or red, a practice supposedly called "tapirage." The frog's scientific name, tinctorius, means "used for dyeing" and reflects the same story. Whether the frog was actually used this way, or whether the effect works at all, is disputed and poorly documented, but the name has stuck for over two centuries.

It is genuinely toxic but well down the scale from the notorious golden poison frog. Its skin secretes pumiliotoxins and related alkaloids that cause pain, muscle cramps, and in sufficient dose cardiac problems in an animal that bites it; a predator that mouths one learns quickly and spits it out, and the bright pattern reinforces the lesson. For a person, handling a wild dyeing poison frog is inadvisable — the toxins can be absorbed through broken skin or transferred to the eyes and mouth — but it is not the kind of frog that can kill you by touch. Crucially, the frog cannot make the poison itself — it sequesters alkaloids from the ants and mites it eats, so captive-bred frogs fed on fruit flies are harmless.

Dendrobates tinctorius is famous for having dozens of distinct, locally fixed colour morphs — some mostly yellow, some white and black, some deep cobalt blue, some with fine marbling, some blocky — each confined to a particular hill, river basin, or patch of forest, with sharp boundaries and few blended forms in between. Because the frogs are toxic and advertise it, one idea is that predators in each area learn one local "warning label," which selects against oddly coloured individuals and locks each population into its own pattern. Isolation on separate rocky outcrops and hills across the Guiana Shield, with little movement between them, then lets the patterns drift apart. The blue "Azureus" frog, once treated as its own species Dendrobates azureus, is now regarded as one of these morphs.

Yes, and it is one of the most involved forms of parental care among frogs. A female lays a small clutch of eggs in leaf litter on the forest floor, and the male returns repeatedly to keep them moist and defend them. When the eggs hatch, the male backs into the mass, lets one or two wriggling tadpoles squirm onto his back, and then climbs — sometimes several metres up a trunk — to deposit each tadpole in a small pool of water held in a tree hole or a broken palm frond. He distributes the tadpoles among several such nurseries so that a single predator or a drying pool cannot wipe out the whole brood. The tadpoles of this species are aggressive and cannibalistic, which is part of why they are kept apart.