Behavioral thermoregulation inlittorina irrorataby climbing

Littorina irrorata exhibit a positive relationship between substratum temperature and the probability of climbing Spartina alterniflora stems in coastal salt marshes. In August, 1988, at Dauphin Island, Ala., we examined whether or not relationships existed between snail internal temperatures and mud substratum temperature, air temperature, height of snails on vegetation, and plant stem temperatures within low and mid‐intertidal zones. Snails observed at >2cm height on Spartina stems exhibited significantly lower internal temperatures than those found close to the substratum. Snails close to the substratum exhibited a positive relationship between internal temperature and mud temperature, while a negative relationship existed between snail temperature and height on stems for snails elevated above 2 cm. Immobilized snails heated artificially in the laboratory did not reduce their internal temperatures. Therefore, we conclude that climbing behavior enables snails to thermoregulate, avoid mortality due to thermal stress, and avoid aquatic predators.