The shed skins of snakes often arouse curiosity among those who find them, but in actual fact, all animals shed their skins. This is not obvious in mammals such as humans, as it is an ongoing, unnoticed, process in which dead cells are continuously coming off. Reptiles, however, are different in that they shed periodically, and in the case of snakes, the entire skin normally comes off in one piece, a procedure that can be likened to removing a sock. This shedding is not without purpose: snakes replace their skins to allow for growth, as well as to remove parasites along with the old skin.
As a snake grows, its skin becomes stretched and worn. A point is reached when it cannot accommodate further growth, so a new skin grows underneath. When this is complete, the old skin will be discarded, along with any parasites it may have picked up. The new skin retains the same patterns and colors as the old.
Prior to shedding, a snake’s skin becomes pale and dull, and the eyes turn a bluish-white shade. This is due to a layer of fluid building up between the old skin and the new one underneath. During this period, captive snakes may be nervous and irritable, possibly because they cannot see properly until the old skin becomes detached from the head. They will not normally eat in the days leading up to shedding and will tend to hide, as they are vulnerable at this time.
Once the new skin has fully developed, the old skin is no longer firmly attached to the snake’s body, and shedding can begin. Sometimes, the reptile will immerse itself in water immediately beforehand. The snake will generally assist the process by brushing against something hard and rough, like a rock, and creating a rip in the surface, usually in the nose and mouth area. The snake continues to work on this rip until the skin comes off, inside out, in one piece.
Snakes shed quite frequently, but exactly how often depends on the species, the quantity and quality of food it eats, and, most of all, the age of the reptile. The average is two to four times per year, but young snakes, since they are growing more rapidly, may shed their skins every two weeks. When they reach adulthood, however, growth will have slowed, and they may only do it twice a year.
Shedding is not always without incident, and sometimes things can go wrong. For example, if the humidity in the air is too low, the skin can be too dry to shed. Portions of the old skin that remain attached can harbor parasites or provide a breeding ground for diseases. Furthermore, if the skin at the tip of the tail fails to detach correctly, it can cut off the snake’s blood flow over time and actually cause the end portion of the tail to come off.
When the old skin is shed, it doesn’t look exactly the same as its replacement. The skin takes on a nearly transparent appearance, and, due to stretching, is larger than the snake. It can still, however, be used by an expert to identify the snake if the person who finds it in her backyard is concerned that it could come from a venomous species. To have it identified, the individual can collect as much of the skin as possible and take it to a science museum, a zoo, a science center, or an individual with an in-depth knowledge of snakes. To preserve the snakeskin while in transit, it should be placed in a protective container.