Plains Spadefoot (Scaphiophus bombifrons)
Western Toad (Bufo boreas)
Great Plains Toad (Bufo debilis)
Woodhouse’s Toad (Bufo woodhousei).
The toad is important mythologically. The sun and the moon are considered the children of Heaven and Earth. Each one tried to court the creatures of the earth. The moon, transformed into the form of a porcupine, enticed the human woman up to the heavens. The sun enticed the toad up to the heavens (“I have found that the toad excels in beauty and form. When the toad looks at me, she not does not make faces like the human woman. She gives her attention to me without a single wrinkle about her eyes, and has a very pleasing mouth. She has a disposition to love dearly” - Dorsey p. 214). The toad got mad at his sister-in-law, the human woman (or perhaps jealous of her), and jumped to the breast of the moon, leaving the sun behind. The woman later went back down to earth, but the toad has remained with the moon ever since. When the new moon rises, you see the toad.
That same image also represents the menstrual flow of the woman, however. The first menstruation is said to have occurred when the human woman eloped with the moon. Thus the toad, who replaced the woman, is linked to this idea of menstruation.
The human woman became pregnant with a child by the moon. When she went back down to earth, she took the child with her. But they say that the toad which took her place with the moon looks like a pregnant woman, though others link the tadpole (hisei-nootee = ‘woman’s stomach’) with the pregnant woman.
In Sun Dance ceremonies, the woman personifies the moon ritually, since the moon (and the toad) are connected to menstruation and pregnancy.
Frogs and probably toads as well were often used in the design of navel-cord amulets, as were tadpoles - no doubt for reasons related to the mythological beliefs described above. See The Arapaho, p. 58.