Why do some frogs have poisonous skin?

Poison dart frogs and some other amphibians store toxic compounds in their skin glands. These chemicals can make predators sick, painful, or even lethal depending on the species and dose. In many cases, the frog’s vivid colors serve as aposematic warning signals, advertising danger. Some toxins are obtained indirectly from the frogs’ insect-based diets, while others are made or modified by the animal. This defense system is a major reason poison frogs became famous in both biology and indigenous hunting traditions.