The Olm (Proteus anguinus), also known as proteus, is strictly aquatic. It retains the characteristics of its larval stage, including external gills. This salamander species lives solely in underwater caves and has lost its sight and skin pigmentation.
Olms are found in the bedrock in the streams of central and southeastern Europe. It can grow to 12 inches and has an average lifespan of 58 years.
