Mmmm not sure about that. I suppose it depends on what you call "Pants".
There were any number of non-riding societies in North America where they wore leggings.
Having your legs covered while going through brush is a major advantage.
" These days, pants are our garment of choice. But for years, our ancestors draped themselves in tunics, robes, and gowns, until someone decided they were tired of having the wind up their skirt. So, what prompted the change? When, exactly, did two-legged trousers become a thing? A recent archaeological discovery gives us a clue. Archaeologists Ulrike Beck and Mayke Wagner of the German Archaeological Institute in Berlin excavated two ancient graves in a cemetery in Xinjiang, China and, among the remains, discovered two pairs of well-preserved woolen pants. Radiocarbon dating puts them at between 3000 and 3300 years old, making them the oldest-known pair of trousers ever discovered. This historical time period corresponds with the rise of “mobile pastoralism” in Central Asia—nomads began moving their herds across the land, and they did so on horseback. Tunics and robes weren’t comfortable or conducive to long, bumpy rides—and battles—so these ancient people innovated. They created pants."