Juvenile snapping turtles may be highly susceptible to dehydration during overland movement because of their aquatic nature and large surface area to volume ratio. The present study examined the influence of body size and relative humidity on rates of evaporative water loss and estimates of survival time. Larger hatchlings had higher rates of evaporative water loss but longer survival times resulting from their greater absolute water contents. Rates of evaporative water loss decreased, and estimated survival times increased with increasing relative humidity. The findings suggest that evaporative water loss may be an important factor influencing survivorship and behavior during overland movements of juvenile snapping turtles.