The fact humans are able to track them is how we know the zodiacs are no longer accurate. According to astrology if you were born on Dec. 1 for example, you’re considered a Sagittarius… except you’re ACTUALLY a Scorpio, due to the constellations shifting.
Only half of the Zodiacs are inspired from real animals. Gemini is two humans, Virgo is a virgin woman, Libra is a Weighing Scale, Sagittarius is a Centaur with a bow, Capricorn is a Sea Goat, and Aquarius is… a cup of water, I guess?