The Mexican hooknose snake is usually in total length (including tail).
H.M. Smith and
Brodie (1982) report a maximum total length of 47.9 cm (almost 19 inches). It is typically brown or gray in color, with as many as 60 brown or brown-green blotches down the back, which are elongated to almost appear as stripes. Its underside is white or cream-colored. Its most distinctive feature is an upturned snout, much like
hognose snakes, which gives it its common name. However, unlike hognose snakes, the Mexican hooknose snake has smooth
dorsal scales. Also distinctive is the arrangement of the head shields. There are no
internasals, and the
rostral separates the
prefrontals and contacts the
frontal. The smooth dorsal scales are arranged in 17 rows at midbody. The
ventrals number 126–155, and the
subcaudals number 28–41. ==Behavior==