791. Riding an Animal on Shabbos

Shabbos 21:8

One may not sit on the roots of a tree that extend higher than three handbreadths from the ground (about nine inches). If the roots are within three handbreadths of the ground, they are considered like part of the ground. If the roots go from three handbreadths above the ground to within three handbreadths of the ground, one may make use of them. If they are three handbreadths above the ground or if there is a recess of three handbreadths, one may not sit even on a section that is level with the ground.

Shabbos 21:9

One may not ride an animal on Shabbos. This is a preventive measure out of concern that one may come to cut a branch for use as a switch. We may not hang from an animal, nor climb onto an animal before Shabbos in order to continue sitting on it on Shabbos. We may not support ourselves by leaning on an animal but we may support ourselves using things that are hanging from an animal. If a person climbs a tree on Shabbos unaware that it is prohibited, he is permitted to climb back down. If one climbed a tree in willful violation of the prohibition, he is not permitted to climb back down. However, if a person should one mount an animal on Shabbos, even in willful violation of the prohibition, he is permitted to dismount. This leniency is extended in order to prevent needless discomfort to the animal. Similarly, we may unload an animal on Shabbos in order to alleviate its discomfort.