What is that thang?! A lizard? A worm? Reptile? Amphibian?
Salamanders and Newts are one and the same. Both are amphibians in the order, Caudata, and newt is a common name of a family of relatively small salamanders. They have moist, soft skin but lack scales, claws and external ear openings like lizards. Size is variable from less than 2" to the Giant Salamander of Asia at 4.9 feet!
The one pictured here is a Rough-skinned newt (Taricha granulosa) and very common in northern California. The bright orange ventral side is a good indication this newt is using aposematic coloration to ward off predators and, sure enough, the genus Taricha produces a particularly potent neurotoxin called, tetrodotoxin. This is the same toxin found in pufferfish and other marine animals. And, like poison dart frogs, the toxin is only absorbed if ingested. Newts feed on invertebrates and aren't able to bite people with any consequence although, I wouldn't want to throw down with that Giant Salamander!
On the Osa Peninsula in Costa Rica, we typically encounter worm salamanders in the genus, Oedipina. With their narrow build, long tail, tiny legs and feet, these salamanders resemble earthworms at first glance. Lungless, these salamanders are believed to breathe through their thin skin and mucous membranes in their mouth! The space where their lungs would be is occupied by a tongue that may measure up to 80% of body length in some species. Fossorial in nature, these creatures spend much of their time burrowing in search of millipedes and small prey living in detritus of the organic soil horizon. Reproduction is external with the male depositing a cone-shaped spermatophore on the forest floor and the suitably romanced female picking it up with her cloaca.
Perhaps the most incredible attribute is their ability for regeneration. Like lizards, salamanders can detach their tail to avoid preadation. However, salamanders will regenerate their tail complete with all their vertebrae! This has far reaching implications for spinal injury repair should researchers unlock the mystery of this adaptation.