Immobilization & Cryptic Coloration
Immobilization is usually the initial response to a potential predator by most caudates. Immobilization consists of cessation of all movement and flattening of the body so as to blend into the immediate environment. If immobilization is not effective, a defense posture may be exhibited (unken reflex), along with toxic secretions, tail-lashing, biting, writhing, flipping over, etc., depending on the species. Because of their slow metabolism, caudates would benefit more from not being noticed, rather than having to make a quick get away (like frogs). This is why it's rather easy to find terrestrial caudates in the wild; they don't put much effort into running from you! Aquatics, on the other hand, are very agile and swift in the water and can dart out of harms way with little effort. Darting is usually the first and only defensive maneuver of aquatics, although if cornered, more aggressive species, such as amphiuma, hellbenders, and mudpuppies, may inflict painful bites.

To reduce the risk of detection, many species have evolved coloration that closely resembles their natural habitat. The photo at right shows a rather effectively camouflaged Desmognathus marmoratus.

Defensive Posturing, the Unken Reflex, & Aposematic Coloration
 Many newts and salamanders are inconspicuously colored dorsally to blend into their habitat (cryptic coloration), but possess  brightly colored bellies to warn of their toxicity (Cynops, Triturus, Paramesotriton, Rhyacotriton etc.). When such species are adequately disturbed, they will assume a defensive posture that shows the brightly colored belly and underside of tail in an attempt to clarify their toxicity. A common defensive posture of the family Salamandridae consists of flattening the abdomen, and curling the tail and head back to show the bright belly. The salamander may assume a circular shape, semi-circular shape, or simply raise the head to display the bright colors. This posturing is a natural reflex stimulated by persistent disturbance, called the unken reflex. The unken reflex is typical of the genera Taricha, Triturus, Cynops, Rhyacotriton, and more. While in position, toxic secretions are usually administered from paratoid glands. In most species, the body becomes extremely tense when in the unken position.

Disruptive Coloration
Some species may be colored in a manner that breaks up the silhouette of the animal on certain backgrounds. Such coloration often looks bold and conspicuous to the human eye, especially when viewed outside of the natural environment, but is actually a rather effective method of evading or confusing predators. Disruptive coloration is found in many animals, including fish and mammals, and may be expressed as dark bands across the eyes or stripes and blotches covering strategic body areas. In Salamanders, disruptive coloration is often displayed as contrasting coloration about the proximal portions of the limbs. This essentially breaks up the silhouette by disguising the presence of the limbs, which may result in the salamander going unnoticed by potential predators. The photo at righ shows such coloration about the limbs in a juvenile Ensatina eschscholtzii xanthoptica.

Head Butting
Other caudates, such as some Ambystomids, portray a "head-butting" technique. This consists of holding the body high off the ground, bending the head down to portray the paratoid glands at the back of the head, and swinging the back of the head toward the predator. This ensures that any potential predators first taste will be a mouthful of poison. Head butting is usually displayed in large species, possessing very large paratoid glands, and is typically enacted in conjunction with the secretion of toxic fluids. 

In the photo at right, of Ambystoma gracile, notice the large glands behind the head. This species does not possess aposematic coloration, like some other poisonous species, but usually doesn't have a problem clarifying its toxicity to potential predators. Head butting is usually a secondary defense method, performed if immobilization is unsuccessful. Ambystoma gracile, and other species, will secrete a milky, toxic substance from the glands during the head-butting display, and sometimes lash the tail, as well.

Tail Lashing, Tail Undulating, & Tail Autotomy
Tail lashing is exhibited by caudates with toxic concentrations in the tail, and by those that can autotomize their tails. Tail lashing consists of forcefully lashing the tail back and forth in a whip-like manner. This draws the attention of the attacker to the tail, which is advantageous to the salamander for two reasons: 1) The attention is now drawn to a highly-toxic part of the salamander, and away from the head and abdomen area, 2) The tail can withstand significant damage without long term harm to, or the death of the salamander, and can be regenerated if bitten off. Some species, especially Plethodontids, do not possess tails strong enough to exhibit tail lashing, and instead undulate the tail in a vertical or semi-vertical position. Like tail lashing, tail undulating is meant to draw the attention of the attacker to the tail region, where high concentrations of toxins await. Some species can also autotomize the tail (drop if off), allowing a brief moment for escape. 

The tail can be regenerated, however this takes energy and food reserves, and also prevents the salamander from using this defense again in the near future. For these reasons, tail autotomy is usually a final effort. The in this section shows an Ensatina eschscholtzii klauberi with a partially regenerated tail. Regeneration is a costly process in this species; one that can take up to two years. Tail autotomy in species that rely heavily on energy reserves stored in the tail may have difficulty during their active time of the year, which may prevent reproduction until the tail is mostly regenerated.

Coiling, Rolling, & Mimicry
Some species, such as those of the genera Batrachseps and Hydromantes, will coil the body into a tight spiral when disturbed. Coiling has an added benefit for some populations of Batrachoseps attanuatus, a species that may display a dorsal stripe in such a manner that it resembles a distasteful millipede. If this does not work, B. attenuatus may begin flipping over in an abrupt and violent manner in an attempt to confuse its attacker. B. attenuatus can also autotomize its writhing tail in an attempt to distract its attacker, which may give the salamander a moment to sneak away unnoticed.

Hydromates platycephalus, and possibly other Hydromantes species, have taken coiling a setup further. They use their steeply sloped habitats as a means of escape in a coiled position. Basically, they coil up and roll away down the steep slope. This species inhabits the steep slopes of the northern Sierra Nevada, California, where rolling down a hill can provide a very quick and efficient escape, and when executed properly, leaves an attacker in a state of confusion. 

Mimicry of more toxic salamander species is observed in some species, such as Pseudotriton ruber. This bright red salamander is thought to mimic the red coloration of toxic efts of the species Notophthalmus viridescens viridescens. Western subspecies of Ensatina escscholtzii, namely the xanthoptica subspecies, are thought to be mimics of the highly toxic Taricha newts, with dark brown dorsa and yellow colored eyes and surrounding ocular areas. 

Special Adaptations
The paratoid glands of most amphibian species are activated when pressure is applied, resulting in the rupture of the glands. Salamandra salamandra spp. however, are capable of spraying poison from their paratoid glands up to seven feet. This is accomplished by the contraction of muscles surrounding the paratoid glands. S. salamandra will aim the poison spray at its attacker by tilting the body in the required direction. A close-up view of a fire salamander reveals dozens of pits along the dorsum and paratoid glands. In addition to their ability to use their toxins as a direct defense when disturbed, this species displays its aposematic coloration about the entire body. The photo to the right shows Salamandra salamandra gigliolii.     

Pleurodeles waltl and Echinotriton andersonii, and possibly a few other species, have a unique defense in addition to their toxicity. These species possess paratoid glands situated dorsolaterally along the sides of body, just above the rib peaks. If threatened, these species can rupture the paratoid glands with the rib peaks when pressure is applied, such that the rib peaks break the surface of the skin. This gives the predator a mouthful of concentrated poison, and essentially injects the poison into the soft tissues of the attacker. P. waltl in particular is mostly aquatic, and so tends to use quick escapes as the primary defensive method. 

Toxicity & Aposematic Coloration

Quick Getaway
Instead of immobilization, as in caudates, anurans opt for a quick getaway when harassed. The preferred course of action to a disturbance is a quick leap out of the vicinity. An abrupt leap away usually confuses potential predators long enough for the frog to make a few more leaps to a safe distance from the disturbance. This behavior is especially notable in treefrogs that leap long distances between leaves.

Defensive Posturing, the Unken Reflex, & Aposematic Coloration
Like caudates, some toxic anurans also display the unken reflex when disturbed. This is common in Bombina spp., the fire belly toads. Like caudates, the purpose of the unken reflex is to clarify the animals toxicity by displaying aposematic coloration. Fire belly toads are inconspicuously colored dorsally (cryptic coloration), but possess vivid colored bellies (aposematic coloration). Toxic secretions are usually administered from paratoid glands, and the body becomes extremely tense when in the unken position. Some species will also bloat the body, in an attempt to appear much larger. The photos at left and right show Bombina variegata displaying the unken reflex. In the photo on the left, the toad has flattened the body, and gone into a "back bend" position to show the brightly colored areas of the venter. The photo on the right shows B. variegata flipped over on its back to reveal the entirety of the yellow belly.

Cryptic Coloration & Mimicry
Many amphibian species are colored in such a way so as to blend, undetected, into their immediate environment. This is called cryptic coloring, and is found in varying degrees among many amphibian species. The photo to the left shows four Hyla versicolor clinging to a tree trunk. Their varying greenish gray coloration allows them to blend nicly into the trunks, branches, and mosses of their habitat. Even when the image is enlarged, the frogs appear remarkably camouflaged. 

Some species have developed coloration and patterns to specifically mimic another organism. When disturbed, these species will flash an area of the body that resembles another animal, which is confusing to the harasser. The mimicked color pattern is usually that of the eyes of a predator, such as an owl or a snake. This type of mimicry is called Self Mimicry, and occurs when one species possess certain markings, usually eye-spots, meant to fool the predator into thinking the prey is a more dangerous animal. Although this is usually not enough to completely deter a potential predator, it may allow the amphibian a narrow opportunity to leap away while the harasser tries to figure out what's going on.

Some have gone a step further, and entirely mimic other species. Dendrobates imitator has been noted as imitating the color patterns of other sympatric Dendrobates species, with remarkable accuracy. This form of mimicry is called Müllerian Mimicry, and occurs when two toxic or noxious species mimic each others aposematic coloration. When a predator learns of the toxicity of a particular individual, it will relate the color scheme of the particular frog to the bad experience in the future, and will more than likely ignore similar looking frogs. This is thought to be a "safety-in-numbers" mechanism that works by reducing losses due to curious predators that have yet to learn about poison frogs. For comparison photos, see Müllerian mimicry in Dendrobates frogs near Tarapoto, Peru. 

Startling Patterns - Shock Mechanism
Some amphibians, many of which are not actually toxic, possess certain physiological adaptations for the purpose of shocking potential predators, giving the frog a moment to leap away. This is most noted in the surprisingly large, red eyes of the frog Agalychnis callidryas, the red-eyed tree frog. During the day, this little frog camouflages itself by clinging to the undersides of green leaves, with any colored part of the body hidden from view. If disturbed, A. callidryas will suddenly open the huge, red eyes, which may be startling to the harasser, giving the frog a moment to escape. A. callidryas also possess bright colors about the sides of the abdomen, that could be passed off as aposematic coloration to unwitting predators. Bright colors are found on many non-toxic frogs, and are flashed at harassers in an attempt to confuse or fool them into thinking the frog is actually toxic.  The photo on the left shows A. callidryas with eyes open, and bright coloration showing. When sleeping, this frog closes a mesh-like lid over the bright colored eyes, and hides the orange feet and colored abdomen under the body.