Why Do Dogs Have Anal Glands?
QUICK ANSWER
Dogs have two small anal glands (anal sacs) located on either side of the anus that produce a pungent, oily secretion used for scent marking and identification. When these glands become impacted or infected, they can cause discomfort, scooting, and a distinct fishy smell.
If your dog suddenly smells like fish, the mystery probably isn't what they ate. It's almost certainly their anal glands. These tiny sacs are one of the least glamorous parts of dog ownership, but understanding them helps you catch problems early.
What do anal glands actually do?
Every dog has two small glands located just inside the anus at roughly the 4 o'clock and 8 o'clock positions. These glands produce a strong-smelling, oily fluid that's unique to each dog, essentially a chemical ID card. Under normal circumstances, the glands empty a small amount of this fluid every time your dog poops. The secretion coats the stool and leaves a scent marker, which is why dogs are so interested in sniffing each other's poop and rear ends. It's their primary tool for individual recognition and territorial communication.
Why does my dog smell like fish?
That fishy smell is the anal gland secretion, and you're usually smelling it because the glands expressed at an inopportune time (like when your dog was stressed, startled, or sitting on your couch). Some dogs also leak small amounts of fluid when they're relaxed or sleeping. If the smell is persistent rather than occasional, it could mean the glands aren't emptying properly on their own, which leads to impaction.
What happens when anal glands get impacted?
When the glands don't empty naturally during bowel movements, the fluid builds up and thickens, creating discomfort and pressure. Signs of impacted anal glands include scooting (dragging their rear on the floor), excessive licking of the rear end, a persistent fishy odor, and visible swelling near the anus. If left untreated, impacted glands can become infected and eventually abscess, a condition the Merck Veterinary Manual notes is painful and may require antibiotics or surgical drainage, . Your vet or a groomer can manually express the glands if they're not emptying on their own.
Do all dogs need their glands expressed?
No. Most dogs' anal glands empty naturally without any intervention. Routine manual expression isn't recommended unless your dog is having problems, because unnecessary expression can actually cause inflammation and make the issue worse over time. Small breeds are more prone to anal gland issues than larger dogs, and dogs on soft diets may have softer stools that don't create enough pressure to empty the glands naturally. If your dog is scooting or smelling fishy regularly, have your vet check the glands and recommend a plan based on your dog's specific situation.
Anal glands are a normal part of canine anatomy that most dog owners never have to think about. When they work properly, they empty on their own. When they don't, the signs are pretty obvious (and pretty smelly). If your dog is scooting, licking excessively, or emanating a fishy odor, it's time to get those glands checked.
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