Anal Sacs (or Anal Glands) are two small glands located just inside your pet’s anus (bottom), at the 4 o’clock and 8 o’clock positions. Each of these glands has a tiny duct or tube, which has an opening into the rectum. The secretion that comes from these glands is very smelly, often brown in colour and is about the consistency of water or oil. Anal Glands serve no real purpose in domestic pets, just like your appendix, however in past times they were used primarily for territorial marking, as a defence mechanism (i.e. like a skunk) or as a form of communication.