Because most of the constellations through which the ecliptic passes represent animals, the ancient Greeks called it.... constel style:

Because most of the constellations through which the ecliptic passes represent animals, the ancient Greeks called its zone zodiakos kyklos, circle of animals, or ta zodia, the little animals. The size and number of zodiacal constellations varied in antiquity and became fixed only with the development of mathematical astronomy. The list below gives the constellations of the zodiac, with the dates of the sun's passage through them in the era when their boundaries were fixed. These dates are still used for the astrological signs, though precession of the equinoxes has shifted the constellations eastward; e.g., on January 1 the direction of the sun is now in S Leo (Lion): July 23Aug. 19March 20 MLA style: "zodiac." APA style: zodiac. style: "zodiac." constel style: