Humans and animals all have shadows which behave the same way. This riddle describes some features of shadows generally, including their changing position as a result of the direction of the light. The suggestion that a shadow would be in front of the person while traveling implies that the person would be walking away from the sun. However, when sitting, the shadow is said to be behind the person; this would imply that the light source is in front of the person, which is consistent with how many people orient themselves around indoor lights, like fires or lamps.