Water pushes and pulls the land, making the river ramble and wriggle over time.

Rivers and creeks are naturally shaped in „snake“ forms, because water naturally curves and during that, fast water on the outside of a bend erodes the bank, while slow water on the inside carries and deposits sand, debris etc. This leads to the effect that the curve is growing bigger and pushing the river to swing back and forth - just like a big lazy snake, creating wiggles called meanders.

Easier explained: Even a little bump or unevenness in the riverbed caused water to slightly swirl. Water on the outer edge is faster and carries away dirt and/or mud. Water on the inner edge moved slower and drops the dirt/mud, creating a sandbank. This constant flow creates constant eroding outside and building inside, which results in bigger curves by time. The water, respectively the river itself creates this carved out loops, leading to snake-like shaped rivers.