Puppies instinctively know how to suckle so they can nurse. After they’re weaned, most dogs stop the suckling behavior — they’re eating out of dishes like adults. But some dogs pick up suckling behavior as they grow, sucking on items that aren’t food. Your vet can help you determine whether your dog’s suckling behavior is a harmless habit or a problem.
What They Suckle
Just like a toddler might suck her thumb when she’s not hungry, a dog might develop a habit of sucking on nonfood items. This is often a blanket, which has a familiar feel and smell, or a favorite toy. Some dogs start sucking on themselves, often their sides near their hind legs, called their flanks.
Why They Suckle
Several schools of thought regard why adult dogs suck on items or their flanks. Some scientists believe the behavior occurs in puppies who were weaned too early or had to constantly battle siblings from a large litter to nurse. In some dogs, the suckling behavior seems to be linked to anxiety, almost like a child who carries a security blanket. When a dog finds comfort in suckling, it can become a habit that helps calm him when he’s lonely or anxious. In a 2010 study, Dr. Nicholas Dodman, director of the animal behavior clinic at the Tufts University Cummings School of Veterinary Medicine, found a gene shared by Dobermans who obsessively sucked their flanks. This might be a sign that some dogs are genetically predisposed to exhibit suckling behavior.
Suckling behavior that seems habitual, such as sucking on a blanket as your dog lies down to sleep, doesn’t normally signal a major problem unless the object of his choice is his own skin. Sucking on areas of his body can lead to open wounds and infections. Obsessive suckling lasts more than a few minutes at a time, unlike habitual sucking. The dog might suck on an object for hours, not even stopping to eat at mealtime or refusing to sleep. If you are concerned about your dog’s behavior, talk to your vet to see what help is available.