Dog owners often complain about destructive chewing. What are the differential diagnoses, and how can I help owners deal with this problem?
Destructive chewing is very common. Puppies investigate their environment by sniffing, tasting, and perhaps chewing on objects as part of normal behavior. Adult dogs might chew when they are scavenging for food, playing, or merely as a means to satisfy a natural urge to chew and gnaw on objects. In some cases, chewing might be an attention-seeking behavior even if it yields negative attention or results in chasing or scolding. Anxiety, conflict, or high-arousal situations may result in destruction and chewing of the owner's possessions and perhaps attempts to escape by chewing windows, doors, or the area in which the dog is confined. The dog may chew to escape or roam because of inadequate exercise, stimulation, or environmental enrichment. Some dogs may chew windows and blinds as a territorial response to outdoor stimuli. In rare instances, chewing behavior is accompanied by ingestion of inappropriate objects (pica), which may be caused by a compulsive disorder.
Identifying the Motivation
The first step in treating chewing behavior is to identify the underlying motivation. Young dogs and puppies that chew inappropriate items may be engaging in play and exploration. This behavior can happen whether the owner is at home or away. Getting into the garbage or other food areas is usually a food-seeking behavior and may be part of normal dog behavior or may occur when the dog is on a calorie-restricted diet. Dogs that chew at windows, doors, or their crates may be anxious about confinement or being left at home alone, or reacting to outdoor stimuli. Repetitive chewing that is difficult to distract or redirect might be a compulsive disorder. Intact animals may attempt to escape to roam and seek mates. Dogs with limited opportunity for social interaction, playtime, exercise, walks, and poor environmental enrichment may chew as a way to keep occupied.
Keeping a daily diary of chewing episodes, frequency, and when and where such episodes occur may help determine underlying motivation and contributing factors. If the problem occurs when the owner is absent, a videotape may help determine whether separation anxiety or an environmental stimulus such as noise is the source of the problem. The normal routine for exercise and interaction should be explored, including toys and chew items provided to the pet. If the dog steals and destroys household items, the time course for the problem (when does it occur) and whether the pet responds aggressively when the owner attempts to retrieve the items should be determined.
This article discusses treatment options related only to destructive chewing that occurs as play or exploration or because of a lack of appropriate environmental enrichment and chew toys. Destructive chewing resulting from separation anxiety, noise phobias, compulsive disorders, territorial aggression, or stealing are addressed elsewhere.1-5
Begin treatment by redirecting chewing to suitable and appealing alternatives, provide sufficient play and exercise, and preventing access to previously chewed items. Avoid all rewards, either purposeful or inadvertent. Keep food completely out of reach, secure trash and garbage, and avoid chasing the dog and playful tugging at stolen items. Preventing access to areas where the dog might chew is essential. Baby gates, closed doors, and leash control all help prevent unwanted chewing.
If destructive chewing occurs in confinement, other measures may be needed, such as teaching the dog how to be comfortably confined or treating any underlying anxiety that may be contributing to the behavior. Teaching a dog to be comfortably confined must occur slowly and while the owner is nearby so that the dog can learn to be calm. For dogs that suffer from barrier frustration or confinement anxiety, this may be difficult to accomplish; suggestions are in other sources.5
Outlets for Chewing
Rather than focusing on punishment, it is more appropriate to provide acceptable outlets for chewing. Give the dog a choice of chew toys to determine which ones it finds most appealing; some dogs prefer plastic, nylon, or rubber toys, while others prefer items that can be ingested, such as various safe types of bones. Augmenting these toys with food often increases their desirability. Various durable rubber toys are now available that are designed to be stuffed or filled with food or treats. As the dog manipulates the toy it is rewarded with tasty tidbits. To avoid obesity, part of the daily ration can be provided in a manipulative toy that will dispense food when played with. Chews that promote good dental hygiene are another good choice. Reward the dog with attention and praise for chewing appropriate items. Caution owners to check chew items regularly and remove damaged ones to avoid inadvertent ingestion of broken or splintered toys.
Supervision, Exercise, & Reprimands
Supervise puppies at all times to prevent chewing on inappropriate objects and to encourage them to use the toys provided. If supervision is not possible, prevent access to any chewable object or area where chewing may occur.
A dog needs ample opportunity to explore and play and a regular, predictable routine, including social interactions, play, training, and exercise. For many dogs, a daily walk can be very calming and provides exercise and stimulation. A dog that cannot be walked because of other unruly behaviors can be controlled with such devices as head collars and harnesses. Formal training classes can be fun and entertaining for both the pet and its caregivers.
A dog should be reprimanded for chewing only if it is caught in the act. All reprimands must be immediate, humane, and controlled. Inappropriate reprimands can lead to fear and defensive reactions in some dogs, or may serve as a form of attention and reinforcement in others. Noise distractors, such as a shake can, alarm (audible or ultrasonic), or even verbal reprimands, are preferred to techniques involving any form of physical contact. In most cases, pets merely learn to avoid chewing when the owner is present, but without appropriate outlets, the behavior may continue when the owner is out of sight. A head collar with a remote lead attached when the owner is present often allows control from a distance and the ability to redirect the pet to more appropriate chew items.
Another option is to make the areas where the dog is likely to chew aversive. Taste or odor aversion is often the easiest and most practical intervention, but not all pets are deterred by these types of products, especially if no other appropriate outlets for play and exploration are offered. Because chewing is an inherently rewarding behavior, some form of chewing may be a lifelong habit.
What to Do
• Determine the motivation for the chewing behavior: Is it an owner-present or an owner-absent behavior?
• Provide acceptable chew alternatives: Chew toys enhanced with food are often preferred.
• Remove or make inaccessible items that must not be destroyed.
• Provide daily exercise, interaction, and training.
• Avoid physical reprimands.