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Reptiles of Washington


Charina bottae, Northern rubber boa

Description. The Northern rubber boa is a small to medium sized snake that may reach about 80 cm. It has a blunt head with small eyes and a blunt tail. Northern rubber boas vary in color from olive greenish to dark brown, usually with a yellow belly.

Distribution. (GAP Analysis map) The Northern rubber boa occurs throughout much of Washington. Populations are spotty, and individuals can be difficult to find even though they are common in some areas. Outside Washington, Northern rubber boas occur in the mountains and canyons of Idaho, western Montana, northwestern Wyoming, northern Utah, northern Nevada, Oregon, and much of California.

Habitat. Northern rubber boas live in many habitats, including moist forest, dry pine forest, and shrubby habitats. They seem to be more common where there is moisture such as streams or moist soil underground, although the surface soil may be dry.

Cool Biology Facts. The chubby look and loose skin give the Northern rubber boas get their name. They never bite, but instead curl up into a ball when disturbed; they often hold the blunt tail up, and even make fake "strikes" with it. The bones of the tail are fused into a solid block that is very strong. Northern rubber boas often eat young rodents, and they probably use the blunt tail to defend ward off the adult rodents. Many snakes have scars on the tail from rodent bites. Unlike most snakes, Northern rubber boas seem to prefer cool temperatures, and are often active throughout the middle of the night.

Conservation status. Northern rubber boas occur widely in Washington, and can be locally common, even though they may be difficult to observe. Their populations appear to be healthy. Habitat destruction is probably the major threat to local populations of Northern rubber boas.

Charina bottae, Northern rubber boa
Charina bottae, Northern rubber boa
Photo by Brad Moon