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.
Italian crested newt
"T. carnifex" displays a unique hemoglobin and red blood cell (RBC) adaptation in their circulatory system. When newts are induced into anemia, they are able to respire without the need of blood cells, or their body making blood cells. Instead, around two weeks after anemia is induced "T. carnifex" produces a mass of cells that helps to revitalize the already circulating red blood cell mass. Casale et al. found that red blood cells of the newt not only produce hemoglobin, but also ferritin, ribosomal proteins, and proteins assumed to be catalase. These extra proteins were produced in high concentrations in early RBC, but decrease quickly as the cell matures. Casale et al. also found that although hemoglobin production decreases as the RBC matures, the cell creates more protein to aid in hemoglobin production.