Pine snake (Pituophis ruthveni and Pituophis mellanoleucus lodingi) hibernacula
Snakes are often highly selective in the choice of sites for hibernation, and suitable sites can potentially be a limiting resource. Hibernating Louisiana Pine Snakes (Pituopllis ruthveni; N = 7) in eastern Texas and Black Pine Snakes (Pituophis melanoleucus lodingi; N = 5) in Mississippi were excavated to characterize their hibernacula. Pituophis ruthveni hibernated exclusively in burrows of Baird's Pocket Gophers (Geomys breviceps), whereas P. 111. lodingi hibernated exclusively in chambers formed by the decay and burning of pine stumps and roots. All snakes hibernated singly at shallow depths (P. ruthveni mean = 19 cm, max. = 25 cm; P. m. lodingi mean = 25 cm, max. = 35 cm). Pituophis taxa at higher latitudes and elevations hibernate communally and at greater depths. In contrast to Northern Pine Snakes (Pituophis melanoleucus inelanoleucus), none of the pine snakes in our study excavated hibernacula beyond minimal enlargement of the preexisting chambers. These differences are presumably the result of mild winters, an abundance of suitable sites offering sufficient thermal insulation, and reduced predation risk caused by absence of communal hibernation in traditional sites. It is increasingly apparent that, throughout their annual cycle, pine snakes are dependent upon fire-maintained pine ecosystems.