The animal that represents the auspicious day of the month in the United States is the rabbit. This association is rooted in various cultural and historical contexts, with the rabbit being a symbol of fertility, luck, and prosperity. The rabbit's significance as an auspicious creature is particularly evident in Chinese culture, where it is one of the twelve zodiac animals and is associated with the month of March. This influence has spread to other cultures, including the United States, where the rabbit continues to be a symbol of good fortune and happiness.

The rabbit's auspicious status can be attributed to several factors. Firstly, its rapid reproductive capabilities make it a symbol of fertility and abundance. In many cultures, rabbits are seen as a sign of prosperity and good luck, especially during the springtime when they are most active and fertile. This is reflected in the tradition of giving rabbits as gifts on Easter, a Christian holiday that coincides with the spring equinox and is often associated with new beginnings and fertility.

Secondly, the rabbit's association with the moon is another reason for its auspiciousness. In various cultures, the moon is a symbol of magic and mystery, and rabbits are often depicted as moon creatures. This connection is further reinforced by the myth of the Man in the Moon, who is said to be a rabbit pounding grain in a mortar and pestle. The rabbit's role in this myth has contributed to its association with the moon and, by extension, with auspiciousness.

Data supporting the rabbit's auspicious status can be found in various cultural and historical sources. For instance, in Chinese astrology, the rabbit is the fourth animal in the twelve-year zodiac cycle, representing the year of the Rabbit. People born in this year are believed to possess qualities such as intelligence, creativity, and a sense of humor. Additionally, the rabbit is a popular character in Chinese folklore and literature, further solidifying its cultural significance.

In the United States, the rabbit's auspiciousness is also evident in popular culture. The Easter Bunny, a symbol of Easter, is a rabbit that brings eggs and candy to children on Easter morning. This tradition is rooted in the belief that the rabbit is a bringer of good luck and happiness. Furthermore, the rabbit has been featured in various forms of media, such as literature, film, and television, further reinforcing its association with auspiciousness.

In conclusion, the rabbit is the animal that represents the auspicious day of the month in the United States. This association is rooted in its cultural significance as a symbol of fertility, luck, and prosperity. The rabbit's auspicious status is supported by various cultural and historical sources, including its role in Chinese astrology, folklore, and popular culture.