Individual, sexual, seasonal, and temporal variation in the amount of sagebrush lizard scent marks

Although many animals deposit scent marks, previous studies have focused almost entirely on rodents or on the chemical structure of the signal. Here, we study the quantity and temporal pattern of chemical deposition by the territorial sagebrush lizard Sceloporus graciosus, measuring both femoral pore and fecal deposits. Specifically, we tested whether variation in deposition is a good cue of individual and sexual identity and/or whether it is more closely associated with body size and reproductive state, indicators of physiological condition. The results support the latter hypothesis. We found that although the amount of fluid deposited on a single perch (rarely quantified in mammals) carries little information on individual or sexual identity, it reflects the physiological condition and reproductive state of individual lizards and is replenished on a roughly weekly cycle, potentially providing additional information on the producer's activity level. The amount of deposition may thus provide important information to chemical receivers making mate choice and territorial defense decisions. The results further suggest that seasonal increases in gland production allow lizards to mark more sites rather than to influence the quality of the signal on a single perch.