Italian crested newt
When newts are inactive or in oxygen-rich environments, respiration can be done through their skin which accounts for 74% of the cutaneous respiration. However, oxygen-poor environments, such as stagnant ponds, pose a threat to the survival of larval newts. This is because oxygen molecules do not readily dissolve in water, and as "T. carnifex" is an immobile animal, extracting oxygen from water is difficult. Newts consequently have external gills at birth that persist until metamorphosis, which assists survival in low-oxygen conditions.
Alpine newt
Alpine newts typically inhabit forests with good access to water in hilly to mountainous regions. They are mostly absent in forest-poor areas. They populate well in thick deciduous forests, as well as parkland and natural gardens. Outside the spawning season, Alpine newts live terrestrially. During the day it then stays in all kinds of undergrowth. After the adults come out of winter dormancy, they migrate to their spawning pools (forest pools, artificial pools) and live the mating season in cool water.