Poisonous amphibians are amphibians that produce toxins to defend themselves from predators.
Most toxic amphibians are poisonous to touch or eat. These amphibians usually sequester toxins from animals and plants on which they feed, commonly from poisonous insects or poisonous plants. Except certain salamandrid salamanders that can extrude sharp venom-tipped ribs,[1] [2] and two species of frogs with venom-tipped bone spurs on their skulls, amphibians are not known to actively inject venom.
An example of poison ingestion derives from the poison dart frog. They get a deadly chemical called lipophilic alkaloid from consuming a poisonous food in the rainforest. They are immune to the poison and they secrete it through their skin as a defense mechanism against predators. This poison is so efficient, the native people of the South American Amazon rainforest use the frogs' toxins on their weapons to kill their prey, giving the frogs their nickname the "poison dart frog".
| Dendrobatidae Poison Dart Frogs | lipophilic alkaloid toxins: allopumiliotoxin 267A, batrachotoxin, epibatidine, histrionicotoxin, pumiliotoxin 251D | humid, tropical environments of Central and South America | |
| Mantella genus Golden frogs or Malagasy poison frogs | alkaloid toxins | Madagascar | |
| northern corroboree frog (Pseudophryne pengilleyi) | pseudo-phrynamine | Southern Tablelands of Australia. | |
| southern corroboree frog (Pseudophryne corroboree) | pseudo-phrynamine | Southern Tablelands of Australia. | |
| Bruno's casque-headed frog (Aparasphenodon brunoi) | Unknown injectable venom[3] | Brazil | |
| Greening's frog (Corythomantis greeningi) | Unknown injectable venom | Brazil | |
| Panamanian golden frog (Atelopus zeteki) | Zetekitoxin AB, Bufadienolide | Central Panama. | |
| American toad (Anaxyrus americanus) | Bufotoxin | eastern United States and Canada. | |
| Colorado River toad (Incilius alvarius) | 5-MeO-DMT, Bufotenin | southeastern California, New Mexico, Mexico and much of southern Arizona | |
| Rhinella arenarum | Bufotoxin | Argentina from the Chubut Province northward, Bolivia east of the Andes, southern Brazil, and Uruguay | |
| Asian giant toad (Phrynoidis asper) | Bufotoxin | Mainland Southeast Asia and the Greater Sundas. | |
| Colombian giant toad, Blomberg's toad (Rhaebo blombergi) | Bufotoxin | western Colombia (Chocó, Valle del Cauca, Cauca, and Nariño Departments) and northwestern Ecuador (Carchi, Esmeraldas, and Imbabura Provinces) | |
| western toad (Anaxyrus boreas) | Bufotoxin | western British Columbia and southern Alaska south through Washington, Oregon, and Idaho to northern Baja California, Mexico; east to Montana, western and central Wyoming, Nevada, the mountains and higher plateaus of Utah, and western Colorado. | |
| common toad, European toad Bufo bufo | bufotalin, bufalitoxin and bufotoxin | Europe | |
| Asiatic toad or Chusan Island toad (Bufo gargarizans) | Bufotoxin | East Asia. | |
| African common toad or guttural toad (Sclerophrys gutturalis) | Bufotoxin | Angola, Botswana, Democratic Republic of the Congo, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Réunion, Somalia, South Africa, Ethiopia, Eswatini, Tanzania, Zambia, and Zimbabwe. | |
| Japanese common toad, Japanese warty toad or Japanese toad (Bufo japonicus) | bufotalin, Bufotoxin | Japan and is present on the islands of Honshu, Hokkaido, Kyushu and Shikoku | |
| Fowler's toad (Anaxyrus fowleri) | Bufotoxin | eastern United States and parts of adjacent Canada | |
| cane toad (Rhinella marina) | Bufotoxin, Bufotenin | Rio Grande Valley in South Texas to the central Amazon and southeastern Peru, and some of the continental islands near Venezuela (such as Trinidad and Tobago) Introduced in Australia, Florida and Hawaii, Papua New Guinea, the Philippines, the Ogasawara, Ishigaki Island and the Daitō Islands of Japan, most Caribbean islands, Fiji and many other Pacific islands | |
| Asian common toad (Duttaphrynus melanostictus) | Bufotoxin | South and Southeast Asia. | |
| Peltophryne peltocephala | Bufotoxin | Cuba | |
| oak toad (Anaxyrus quercicus) | Bufotoxin | southeastern United States. | |
| African common toad, square-marked toad, African toad (Sclerophrys regularis) | Bufotoxin | Angola, Benin, Burkina Faso, Cameroon, Cape Verde, Central African Republic, Chad, Republic of the Congo, Democratic Republic of the Congo, Ivory Coast, Egypt, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Mali, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Sudan, and Uganda. | |
| Gulf Coast toad (Incilius valliceps) | Bufotoxin | eastern and southeastern Mexico and Central America as far south as Costa Rica. | |
| European green toad (Bufotes viridis) | Bufotoxin | mainland Europe, ranging from far eastern France and Denmark to the Balkans and Western Russia. | |
| Taricha genus Western Newt | Tetrodotoxin | Pacific coastal region from southern Alaska to southern California, and Mexico | |
| Triturus genus crested and the marbled newts | Tetrodotoxin | Great Britain through most of continental Europe to westernmost Siberia, Anatolia, and the Caspian Sea region | |
| Notophthalmus genus | Tetrodotoxin[4] | eastern United States, Mexico | |
| Salamandra genus | samandarin, samandarone, O-acetylsamandarine[5] | southern and central Europe | |
| Iberian ribbed newt (Pleurodeles waltl) | Unknown [6] | central and southern Iberian Peninsula and Morocco. | |
Some people use the bufotoxins of some species of toxic toads as a drug to get high, but this can become very dangerous. Usually due to the toads' size and toxicity, the poisons would not be deadly to a fully grown, healthy adult. But if too much of the toxin is absorbed, or if the person is young or ill, then the poisons can become a serious threat. It also depends on species: some amphibians do have toxins strong enough to kill even a healthy mature person within just a few minutes, while other species may not have toxins potent enough to have any effect. Licking toads is not biologically practical. For these tryptamines to be orally activated, the human monoamine oxidase system must be inhibited. Therefore, licking a poisonous amphibian will not guarantee a sufficient dose.