Not so silent: A review of sound production in salamanders reveals a widespread and potentially diverse acoustic behavior

Despite sporadic reports of sound production in salamanders, they are often thought to be quiet, even mute, creatures. However, our review of the literature demonstrates that at least 48 species, spanning 9 out of the 10 salamander families, are known to produce sound. Sound production therefore is phylogenetically widespread among salamanders, is likely ancestral to batrachians and includes both lunged and lungless species, as well as aquatic/terrestrial and biphasic species. The mechanisms by which salamanders make sound are in many cases unclear, but diverse when known; only one species has vocal cords, but most seem to produce sound via gill slits, nostrils, or other unknown mechanisms. The functions of salamander sounds are similarly opaque, although sound production appears to encompass behaviours including defence, reproduction, territoriality, intraspecific sociality and involuntary noise. Salamanders navigate within a rich acoustic environment, including sound following generated by other caudates. Conservation efforts will benefit from considering the acoustic abilities of salamanders, particularly regarding anthropogenic noise that could disrupt intraspecific communication and muddle acoustically informed breeding migration routes. Increased study of salamander sound production is likely to uncover surprising vocal diversity and shed light on the transition between aquatic and aerial sound production and perception capabilities.