structural:expansion
Molting

Molting (or "ecdysis") serves a number of purposes - it allows old, worn skin to be replaced and can be synced to mating cycles, as with other animals. Molting occurs periodically throughout the life of a snake. Before each molt, the snake regulates its diet and seeks defensible shelter. Just before shedding, the skin becomes grey and the snake's eyes turn silvery. The inner surface of the old skin liquefies, causing it to separate from the new skin beneath it. After a few days, the eyes clear and the snake reaches out of its old skin, which splits. The snake rubs its body against rough surfaces to aid in the shedding of its old skin. In many cases, the castaway skin peels backward over the body from head to tail in one piece, like taking the dust jacket off a book, revealing a new, larger, brighter layer of skin which has formed underneath. Renewal of the skin by molting supposedly increases the mass of some animals such as insects, but in the case of snakes this has been disputed. Shedding skin can release pheromones and revitalize color and patterns of the skin to increase attraction of mates.

Snakes may shed four of five times a year, depending on the weather conditions, food supply, age of the snake, and other factors. It is theoretically possible to identify the snake from its cast skin if it is reasonably intact. Mythological associations of snakes with symbols of healing and medicine, as pictured in the Rod of Asclepius, are derivative of molting.

One can attempt to identify the sex of a snake when the species is not distinctly sexually dimorphic by counting scales. The cloaca is probed and measured against the subcaudal scales. Counting scales determines whether a snake is a male or female, as the hemipenes of a male being probed is usually longer.