Renewal of the epidermal tissues is often assumed to be the primary function of ecdysis in snakes. The semiannual replacement of the skin maintains a barrier against the external environment, with the timing and frequency of this renewal process considered to be a function of growth. As snakes eat and grow, they are forced to shed to accommodate the increase in body size, relating the resource environment to rates of growth and patterns of shed. It has also been suggested that shedding occurs in response to changing abiotic conditions or as a mechanism of semiochemical signaling. Resolution of the causal mechanism(s) that dictates patterns of ecdysis, and its relative importance at the population level, requires a working knowledge of when and how often snakes shed. To date, descriptions of patterns of the timing and frequency of shed events have been limited to laboratory studies and field observations of limited scope. We used 25 yr of radiotelemetry observations of Timber Rattlesnakes (Crotalus horridus) to describe the frequency and timing of shedding at the population level. We found that the frequency of shed events was approximately even between males and females, but that male frequency was related to body condition, whereas female frequency was correlated to reproductive condition. Further evaluation revealed that the timing of shed events in lower body condition males was randomly distributed throughout the year; timing in higher body condition males clustered around the mating season. Timing in females related to reproductive condition, with gravid females shedding early in the year and nongravid females shedding close to the peak in male–female courtship. Our study indicates that shedding patterns in males are coupled to the resource environment and offer support for shedding as a growth function, but in females shedding may be more tightly coupled to reproduction, serving alternate or additional roles in adult female snakes.

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