Newts are intriguing amphibians often found in damp environments. A common question is whether all newts are poisonous. While some newt species do possess toxins, the assumption that every newt is poisonous is a misunderstanding.
The Truth About Newt Toxicity
Not all newt species carry toxins; levels vary. They primarily use these compounds as a defense against predators. Toxins pose a low risk to humans unless ingested or if secretions contact mucous membranes or open wounds. Newts are poisonous, harmful if ingested or absorbed through contact, unlike venomous animals that inject toxins.
Toxins are not injected. Instead, harmful substances are stored in skin glands and released as a secretion when threatened or handled. This deters predators. While some newts are mildly toxic, others, like Pacific Northwest species, possess highly potent compounds.
How Newts Produce and Use Toxins
Toxins are produced in specialized skin glands. The most potent is tetrodotoxin (TTX), a neurotoxin also found in pufferfish and some octopuses. TTX blocks sodium channels in nerve cells, which are essential for transmitting electrical signals. This disruption can lead to paralysis and, in severe cases, respiratory failure.
TTX is acquired from symbiotic bacteria on the skin. These microbes synthesize the TTX molecule, which the newt stores for defense. Despite carrying these compounds, newts have adaptations, like modified sodium channels, granting them resistance to their own toxins.
Common Poisonous Newt Species
California newts (Taricha torosa) and rough-skinned newts (Taricha granulosa) are highly toxic, native to western North America. They contain high concentrations of tetrodotoxin; the rough-skinned newt is often considered among the most toxic amphibians. Toxicity levels can vary even within species, influenced by an evolutionary “arms race” with predators like garter snakes that have developed resistance to TTX.
The European fire salamander (Salamandra salamandra), found across Europe, is another example. While technically a salamander, it shares characteristics with newts, secreting alkaloid toxins like samandarin from glands behind its eyes and along its back. Its bright markings warn predators.
Safe Handling and Encounters
Avoid direct handling of newts due to toxins. If moving a newt (e.g., to guide it away from danger), wearing gloves is recommended. After any contact, wash hands thoroughly with soap and water to remove toxins and prevent exposure to mucous membranes like eyes or mouth.
In case of exposure (e.g., touching eyes or mouth after handling), immediately rinse thoroughly with water. Newts pose a risk to pets if mouthed or ingested. Their toxins cause severe symptoms (e.g., neurological issues, respiratory distress), requiring prompt veterinary attention. Observing newts from a distance allows for appreciation without risk.