Types of boas

Charina is a genus in the family Boidae, the true boas, and it contains the rubber boas of western North America. Two species are recognized: the Northern Rubber Boa and the Southern Rubber Boa. Unlike the large tropical boas most people picture, these are small, stout snakes rarely exceeding about two feet, with smooth, loose-fitting skin that gives them a distinctly rubbery look and feel. Their most telling trait is a short, blunt tail shaped almost exactly like the head, an adaptation that lets them bluff predators about which end is which.

These boas range through the cooler, more temperate parts of the western United States and into southern British Columbia, with the Southern Rubber Boa restricted to a small area of southern California. They favor moist woodlands, montane forests, grassy meadows, and rocky slopes, often near streams. As cold-tolerant constrictors, they are active at lower temperatures than most snakes and spend much of their time hidden under bark, logs, leaf litter, and rocks, which makes them secretive and easy to overlook.

Rubber boas are nonvenomous and among the most docile snakes anywhere. Like all boas, they kill prey by constriction, feeding mainly on small mammals such as young mice and voles, and they will raid nests, using the blunt tail as a shield against defensive bites from adult rodents. They are slow-moving, accomplished burrowers and climbers, and females give live birth to small litters rather than laying eggs. They pose no danger to humans, though as with any wild animal it is best to observe them without handling and to leave them undisturbed in the field.