In Colombia, many grassy hillsides are terraced, like in the photo below. This terracing also occurs on hillsides that never had these palm trees on them. I assume that it also occurs outside of Colombia. How does this terracing happen?
Just from my first-hand observations, I think the answer is: The terracing was formed by grazing livestock. Grazing livestock is common in these areas, and the barbed wire fence hints that it is occurring here. On flat ground, the livestock wander in random directions. On steep ground, the livestock prefer to follow the hill's contour lines, as that is the easiest path to walk, as opposed to more directly uphill or downhill. When a livestock initiates a contour path on a not-yet-terraced hillside, that path is repeatedly trod by subsequent livestock, as it is a little flatter and easier to walk than other contour paths, eventually leading to significant terracing. The terracing is uneven (not level) because the livestock have to go up or down a bit to graze elsewhere on the hill.
Can anybody confirm my answer, or provide another answer that is objectively correct, preferably with citations? I asked the same question in the form of an SE puzzle, which is currently on hold because "This question may invite speculative answers, as the question is not fully defined. The validity of some answers may be based upon opinion. Good questions for this site [puzzling.stackexchange.com] have a limited number of objectively correct answers." I may be able to save the puzzle with a definitive answer here.
Click for high-resolution photo
Photo credit: Angela Calle and Daniel Di Palma [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)] https://commons.wikimedia.org/wiki/File:Valle_del_cocora_-_wax_palm_02.jpg