Defecation is the act or process by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly; sloths can go a week without expelling. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum....