The Rosy Boa (Lichanura trivirgata) is a snake of the Boidae family, and is one of only two members of that family native to the United States (the other is the Rubber Boa (C. bottae)). Rosy Boas are native to the American Southwest, and Baja and Sonora Mexico. As adults they only reach a length of 39in (1m), though some individuals can reach 4ft (1.2m).
Colouration in Rosy Boas is highly variable - the common name is derived from the rosy or salmon colouration that is common on the belly of Rosy Boas originating from coastal southern California and Baja Mexico, but most do not have this ventral colouration and instead have a series of dark to orange spots on a light-coloured background. Almost all Rosy Boas have at least some trace of three longitudinal stripes, one down the centre of the back, and two on the lower sides, the colours of which can be anything from orange to black. The space inbetween the stripes is as equally variable in colour, ranging from shades of gray to yellow or tan.