Normal

The head is predominantly pale with well-defined dark markings. There may be dark shading or barring on some of pale lip scales. There is a thin dark line on the top of the head from the internasals to the nape of the neck. Some specimens have two small lines over each eye. There is a small dark blotch below each eye and a dark horizontal line through each eye that continues as a well-defined dark postocular stripe.

The pale color on the head and most of the body varies from the palest browns, often with yellow or pink highlights, through grayish browns to medium browns ^[2]

The typical common boa constrictor is a pale snake that are primarily colored in shades of brown with a longitudinal series of 20 or more dark transverse bars spaced down the length of the back. These dark bars are each narrowest in the middle of the back and widest at the dorsolateral margin, where they incorporate a pale blotch on each side at the dorsolateral margin.

In some boa constrictor patterns, the dark bars are connected along the sides to form a dark dorsal pattern on the back that outlines pale dorsal blotches that are oval or round. In other patterns, the dark dorsal bars are not connected to other dark elements of pattern.

On the sides are a series of dark blotches with pale centers. Some blotches may contact the dark dorsal pattern. The pale areas of pattern are relatively evenly sprinkled with small black flecks and entire black scales. Generally, the patterns of boa constrictors from Colombia tend to include more bold black scales and even small black blotches on the sides than do the Central American specimens.

On some snakes the sides of the body are pale silver gray with pink or orange highlights. The dark markings are a rich chocolate brown to brownish black, sometimes with thin black margins. The pale dorsolateral spots are yellowish to ivory white. ^[3]

The ventral surface of the neck and anterior body is ivory or pale gray, on the posterior half of the body the stomach becomes increasingly peppered with black smudges, flecks, and spots. ^[4]

The tails are pale with large, oval, black-edged red blotches. This pattern continues onto the posterior body where the red pattern becomes more like bands. Continuing forward from the area of the vent, each successive pale interspace becomes wider as each red band becomes more narrow and less red; in this manner the red pattern of the posterior body and tail melds into the dorsal pattern seen on most of the body.

The pale coloration on the posterior body and tail is typically a medium ivory or pale yellowish tan. On dark-colored boas the red blotches on the tail and posterior body are typically dark brownish black with scattered dark oxblood-red scales; at the other extreme, the posterior red blotches of beautiful pale boas may be nearly solid bright red with thin black margins ^[5]