Rocky Mountain Toad

Bufo lentiginosus woodhousei Girard

Colour: Usually dingy greyish or yellowish brown, with much yellow on the lower sides and on the concealed portion of the femur. The toad may be conspicuously spotted with dark or unspotted, the rounded warts alone being dark-coloured. There is a light vertebral streak. Underparts light yellowish, unspotted, except for aggregations of small black spots on the breast. Eye metallic yellow. Throat of male black. Tips of fingers and toes dark-coloured.
Measurements: Size unusually large, i. e. male 3 1/2 to 4 inches. female 4 to 5 1/2 inches. Head short, its length contained in total length nearly five times. A toad having a length of head seven-eighths inch has a width 1 3/4 inch. The length of the leg to the heel equals the length of the body forward to some point between the eye and the end of the muzzle. Tibia but little longer than femur.
Structure: Skin rough, with rounded warts. Eyelids warty. Parotoids long and oval, not reniform in shape and not descending greatly on the shoulders. Ear a distinct vertical oval, variable in size from a diameter half that of the eye to one which in the case of old specimens almost equals it. The top of the head is usually lifted above the neck region behind. There are two conspicuous bony ridges parallel between the eyes. These may have a groove between them, and may have their edges crenated along this groove or they may be obscured by having the groove quite filled up between them. At right angles behind the eyes these ridges meet two other ridges, each of which extends outward and downward between the eye and the parotoid to the ear on its respective side. Muzzle not projecting greatly beyond the lip. Palm with one large tubercle and a smaller one at the inner base of the first finger. Sole of foot rough, with small tubercles. Web of foot relatively short. Inner tubercle usually large, with free cutting edge. Outer tubercle large, but flat, without cutting edge.
Range: This is the common toad of the Rocky Mountain region. It is reported from Montana, Nevada, Utah, Colorado, Nebraska, Kansas, Arizona, New Mexico, and Texas.

The Rocky Mountain toad is usually dingy in colour. Just after a moult, its colouration becomes brighter and richer in tone, with sharp contrast between the spots and the background. It has great power of change of colour from light to dark.

It is related to the American toad (Bufo americanus), and still more closely to the Southern toad (Bufo lentiginosus), but attains a greater size than either of these. The male of this toad is about the size of the female of the American toad. The relative length of the head and the shape of the cranial crests will always suffice to distinguish it from Bufo lentiginosus. However, its characteristics are so like those of Bufo americanus that in some specimens it is almost impossible to make the distinction, and it would then seem that Bufo l. woodhousei is Bufo americanus with only the variation to be expected from a different geographical distribution. The three toads mentioned are alike not only in general appearance, but in each case the male has a wrinkled black throat, and can extend a rounded vocal throat-pouch. In each case, also, the call given is a vibrated note of high pitch and sweet quality. These calls are difficult to distinguish one from the other, and prove a common ancestor.

This toad is often confused with Bufo cognatus, which is found in many of the same localities. The confusion arises, however, on superficial examination only, as the two toads are very different indeed. The cranial ridges of Bufo cognatus are not parallel, but diverge backward from a prominent bony elevation between the nostrils. The voices of the two are different, and could never be confused after once hearing. That of Bufo woodhousei is sweet and musical, while the other is emphatically the opposite. The vocal pouch of Bufo woodhousei is a rounded sac extending from the margin of the lower jaw to the line on the breast somewhat below the arm insertions and from one angle of the jaw to the other. That of Bufo cognatus is a bladder sent out from the base of the throat in the midline between the arm insertions.

There are many minor differences between the two, such as the following: The foot of Bufo cognatus is relatively much longer than that of Bufo woodhousei the parotoids of Bufo cognatus extend obliquely down on the shoulder, while those of Bufo woodhousei are almost parallel.