A Single gram of poison from Bruno’s casque-headed frog (Aparasphenodon brunoi) is enough to kill 80 humans. The frogs deliver the toxins into the bloodstream of the predator using bony spines that grow out of their skulls which are rooted in glands that secrete the toxic mucous. The frogs live in holes on trees, closing the hole with their heads to maintain humidity inside and reduce water loss from the body. The top of their heads is similar to the barks of trees, making it difficult for a predator to see them. But in case the disguise is identified, it’s impossible for the predator to grab the frog by the head to pull it out of the hole.
Venomous animals have toxins associated with delivery mechanisms that can introduce the toxins into another animal.
Although most amphibian species produce or sequester noxious or toxic secretions in the glands of the skin to use as anti predator mechanisms, they have been considered poisonous rather than venomous because delivery mechanisms are absent.
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