Yes, lizards periodically shed the outermost layer of their skin in a process known as ecdysis. This necessary biological function allows the animal to maintain physical health and accommodate changes in body size. Unlike the continuous, microscopic cell turnover that occurs in mammals, lizards shed their skin in large, visible sections. Hormones control this cycle, ensuring the reptile effectively discards its old, worn epidermis.
Why Lizards Must Shed Their Skin
Ecdysis primarily functions to accommodate physical growth. A lizard’s skin, covered in scales, is relatively inelastic and does not expand indefinitely as the animal matures. Because of this structural limitation, a new, larger layer of skin must be generated beneath the surface to allow for an increase in body size. This is particularly noticeable in young, rapidly growing lizards, which shed far more often than adults.
Shedding also serves as skin maintenance and repair. The outer layer of skin is subject to daily wear and tear, including minor abrasions and damage from environmental elements. By regularly replacing the epidermis, the lizard can remove damaged tissue and renew the skin’s sensory and protective functions.
Shedding is also a natural method of hygiene and parasite control. As the old skin is sloughed off, it takes with it any accumulated bacteria, dirt, and external parasites, such as mites, that have attached themselves to the surface. The presence of external fouling can even trigger an accelerated shedding cycle in some species, indicating its importance for maintaining a clean body surface.
The Distinctive Process of Ecdysis
The shedding cycle begins with the formation of a completely new layer of epidermis beneath the old one. Hormonal changes trigger the creation of a separation layer between the old skin, or stratum corneum, and the fresh skin underneath. This separation is facilitated by the release of lymphatic fluid and specific enzymes into the space between the two layers.
As this fluid builds up, the lizard’s appearance changes. The skin takes on a dull, cloudy, or grayish appearance as the outer layer begins to lift away from the body. In species with movable eyelids, the eyes may also appear cloudy or opaque due to the fluid accumulating under the spectacles, which are the clear, fused scales covering the eyes.
Physical removal of the skin is a mechanical process that can take hours or days. Lizards are characterized by shedding in patches or pieces, which is a defining difference from snakes that typically shed their skin in a single, complete piece. They actively rub against rough surfaces in their environment, such as rocks, branches, and substrate, to catch and tear the loose skin.
Once a tear is initiated, the lizard often uses its mouth to grasp the loose skin and pull it away from the body. This is commonly observed starting around the head and snout before the lizard works the peeling skin down the rest of its body. Some lizard species, such as geckos, will often consume the shed skin, a behavior that recycles valuable nutrients and minerals.
Recognizing Normal and Problematic Sheds
The frequency of ecdysis is highly variable and depends on the lizard’s age, species, and growth rate. Juvenile lizards that are growing quickly may shed every few weeks, while healthy adult lizards may only shed a few times a year. A successful shed, once completed, will result in bright, vibrant, and clear skin across the entire body surface, with no remnants of the old skin visible.
A common issue encountered is dysecdysis, which refers to an abnormal or incomplete shed. The most frequent cause of dysecdysis is insufficient environmental humidity, as proper moisture is necessary for the skin layers to separate correctly. If the humidity is too low, the old skin dries out and adheres tightly to the new skin, making mechanical removal difficult.
Retained shed, or “stuck shed,” is particularly harmful when it remains on the extremities, such as the toes, tail tip, and eye caps. Retained skin on the digits can shrink as it dries, constricting blood circulation and potentially leading to tissue death and the loss of the appendage over successive sheds. Retained eye caps, which look like a persistent cloudy layer over the eye, can impair vision and cause eye infections.
A problematic shed includes pieces of skin remaining on the lizard. The lizard may also exhibit excessive rubbing behavior or appear lethargic due to discomfort. Addressing dysecdysis often involves correcting husbandry issues, particularly humidity, and may require a veterinarian’s assistance to safely remove the tightly adhered skin.