 Although many salamanders have cryptic colors so as to be unnoticeable , others signal their toxicity by their vivid coloring . Yellow , orange , and red are the colors generally used , often with black for greater contrast . Sometimes , the animal postures if attacked , revealing a flash of warning hue on its underside . The red eft , the brightly colored terrestrial juvenile form of the eastern newt ( Notophthalmus viridescens ) , is highly poisonous . It is avoided by birds and snakes , and can survive for up to 30 minutes after being swallowed ( later being regurgitated ) . The red salamander ( Pseudotriton ruber ) is a palatable species with a similar coloring to the red eft . Predators that previously fed on it have been shown to avoid it after encountering red efts , an example of Batesian mimicry . Other species exhibit similar mimicry . In California , the palatable yellow @-@ eyed salamander ( Ensatina eschscholtzii ) closely resembles the toxic California newt ( Taricha torosa ) and the rough @-@ skinned newt ( Taricha granulosa ) , whereas in other parts of its range , it is cryptically colored . A correlation exists between the toxicity of Californian salamander species and diurnal habits : relatively harmless species like the California slender salamander ( Batrachoseps attenuatus ) are nocturnal and are eaten by snakes , while the California newt has many large poison glands in its skin , is diurnal , and is avoided by snakes . 
