What's the Deal With... Anal Sacs?

Anal Sacs
Thinkstock

Nothing raises a stink quite like anal sacs. If you’ve ever noticed a foul, musky odor wafting from your pet, there's a chance that anal sacs are behind it.

Where Are the Anal Sacs?

In dogs and cats, these small pouches, which store sebaceous secretions from the glands within the sac lining, are located in the anal sphincter. The sacs can discharge their contents through two small ducts positioned at about the four- and eight-o’clock positions on either side of the anus. Although the yellow-brown secretions can vary in consistency from oily to creamy, they almost always have an offensive stench.

Why Do Cats and Dogs Have Them?

“Their principle function seems to be for the production of a distinctive odor,” says Dr. Peter Dodson, professor of anatomy at the University of Pennsylvania School of Veterinary Medicine. “The odors may convey information about the general health and stress levels of the pet.”

It’s possible that anal sacs are vestigial anatomical parts that the ancestors of dogs and cats used to defend themselves through spraying. “In certain species, as dog owners sometimes know all too well, the odor-bearing sebaceous secretion can be propelled, as in the case of skunks,” says Dr. Dodson.

Does My Pet Ever Need to Have Them Checked Out?

While most domesticated dogs and cats no longer need to use their anal sacs for defense, the structures don’t appear to be necessary for good health. However, anal sacs can become infected, impacted or even rupture.

Your dog will usually let you know there’s a problem by scooting across your favorite carpet. Pets with anal gland problems may also spend an inordinate amount of time licking their rumps.

If you suspect that your pet may have an anal sac problem, consult with your veterinarian. Adding fiber to your pet’s diet may help, but many pets need to have their anal sacs emptied on a regular basis. Your vet can show you how to do it, although most pet owners prefer to leave this task to the professionals.

For answers to other curious questions about animals, check out our other "What's the Deal With . . ." stories.

Google+

Join the Conversation

Like this article? Have a point of view to share? Let us know!