The anal sacs are located on either side of the anus at the 8 o’clock and 4 o’clock positions; they are positioned just under the skin. They connect to the anus by means of small canals or ducts. Anal sacs produce and store a dark, foul-smelling fluid. These are the same type of organs that a skunk has to scare away its enemies. Although dogs can use these for the same purpose, most dogs live in an environment that has no enemies. Because the sacs are rarely emptied, the fluid builds up, solidifies, and becomes an ideal environment in which bacteria can grow.