Cutaneous respiration
The skin of amphibians is a major site of respiration in all species for which measurements are available. Cutaneous respiration is the sole respiratory mode of lungless salamanders (family Plethodontidae) which lack lungs entirely yet constitute the largest family of salamanders. Cutaneous respiration in frogs and other amphibians may be the primary respiratory mode during colder temperatures.
Concave-eared torrent frog
Concave-eared torrent frog is the first frog (and the first non-mammalian vertebrate) demonstrated to both produce and perceive ultrasonic frequencies. These frogs' preferred habitat is adjacent to rapidly moving water which produces perpetual low-frequency background noise. Thus, the use of high-frequency calls is believed to facilitate intraspecific communication within the frogs' noisy environment.