We breathe through our nostrils. The air goes into our lungs, from which oxygen is carried to our blood. This is how the respiratory system of mammals functions. However, amphibians have a different system. As amphibians live on both land and water, their respiratory system must allow them to take in oxygen not only from the air but also from water.
When amphibians stay in the water, they breathe through their skin, but once they come on land, they breathe with their lungs, and through the membranes in their mouth. Even when the lungs are used, amphibians obtain oxygen through their skin. For this to happen, the skin must remain moist at all times. When an amphibian is in the larval stage, it uses gills for breathing much like fish. These gills later develop into lungs, as the amphibian undergoes the changes that transform it into an adult.
To sum up, amphibians can get oxygen into their bodies in three different ways. The first way is by using their lungs, which are similar to ours. The second way is through their skin, and the third is by using gills. Another curious matter is amphibians do not breathe constantly as humans do. Instead, they just breathe occasionally when their body needs more oxygen.
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