The family Boidae includes the largest living snakes, but the Idaho representative of this family, the Rubber Boa (Charina bottae) is very modest in size.  The 20 genera (Pough et al. 1998) that comprise this family occupy a wide range of habitats and come in a wide range of forms.  There is also variety in the reproductive modes of species within this family.  The pythons (subfamily Pythoninae) are oviparous (egg laying), while boas (subfamily Boinae) are viviparous (live birth), this includes the native Rubber Boa.  A feature common among boas and pythons is the presence of a vestigial pelvic girdle and pelvic spurs, which are remnants of hind limb bones (Goin and Goin 1971).  Once again, the Idaho representative of this family does indeed display this trait.