Salamanders shed their skin in a process scientifically termed ecdysis. As amphibians, they possess delicate, permeable skin that functions as protection and as a respiratory membrane, allowing them to absorb oxygen and water directly from their environment. This shedding is a regular and necessary biological function to maintain the health and function of this organ. The outer layer of skin, called the stratum corneum, becomes worn, damaged, or infected over time, requiring periodic replacement for survival.
The Amphibian Shedding Process
The mechanics of shedding begin when the outermost layer of the skin separates from the new layer forming underneath. A layer of mucus is secreted between the old and new skin, which acts as a lubricant and assists in the separation process. The initial tear often occurs around the mouth, and the salamander must then actively work to push the old skin backward over its body.
To physically remove the loose skin, the salamander will often rub its face against a rough object, such as a rock, plant, or the substrate, to initiate the tear. Once started, the animal uses a series of body ripples and movements to peel the skin off from head to tail. Unlike the single, complete shed often associated with snakes, salamander skin frequently comes off in large pieces or may even be peeled off using its mouth. This active removal is a relatively quick process, sometimes taking only a few minutes.
The Fate of the Shed Skin
Almost immediately upon removal, the salamander engages in a behavior known as dermatophagy, which means consuming the shed skin. This may seem unusual, but it serves a clear biological purpose for the animal. The old skin contains valuable resources, including proteins, fats, and minerals.
By eating the shed skin, the salamander reclaims these nutrients, which is an efficient way to recycle biological material and reduce the metabolic cost of producing new skin. This behavior also serves an ecological function by removing evidence of the animal’s presence, helping to maintain a clean environment and prevent the shed skin from attracting predators or becoming a source of parasites.
Why and When Shedding Occurs
Shedding is primarily driven by the need to support growth and maintain optimal skin function. For younger, actively growing salamanders, the frequency of ecdysis is high, sometimes occurring every few days to accommodate rapid increases in body size. As the animal matures and its growth rate slows, shedding becomes less frequent, potentially dropping to once a month or longer.
The shedding cycle is closely linked to the salamander’s metabolic rate, which is influenced by external factors like temperature and hydration. Warmer temperatures, which increase metabolism, often lead to more frequent shedding. Sufficient moisture is needed for the skin layers to separate properly. Shedding also acts as a repair mechanism, allowing the animal to remove accumulated pathogens, parasites, or minor damage.