The New Addition: Pet Aggression toward Baby

Last month I reviewed some strategies for preparing your pet to welcome home a new baby. As I discussed, most of these introductions go smoothly and dogs, cats, and kids grow up happy and healthy together. In some cases, however, the dog or cat may show some worrisome behavior when meeting a new baby and some of these situations can be quite serious indeed. When a dog or cat shows aggression toward a baby, for example, the new parents are often faced with some very difficult decisions that may include keeping the baby and animal separated or even permanently rehoming the animal.

For most dogs and cats, a baby or child is not automatically lumped into the same category as an adult. While they have the same general body structure and share many characteristics with their grown parents, babies and children sound, move, and interact with the world in ways that are quite distinct from those of adults, and our companion animals can be attuned to these differences. Babies make strange, high-pitched wailing sounds when they cry (and boy, do they spend a lot of time doing that!), they flail their arms and legs about in jerky, kicking motions, and they spend all their time laying down for the first several months. These physical differences can be alarming to some animals, who may respond with defensive aggression when they are near the baby. In other cases, the baby’s sounds and small size seem more like that of a possum than a person, triggering dangerous predatory instincts in dogs and cats. When warning signs of aggression toward babies or children are observed, it is essential that pet owners seek an immediate assessment and behavioral intervention from a Certified Applied Animal Behaviorist (CAAB) or board-certified veterinary behaviorist.

What might a warning sign of aggression look like? In dogs, fear or discomfort is often first expressed as stiffness in the dog’s body or facial expression. If we observe the dog closing her mouth, tightening her cheeks, pinning her ears or moving them into forward alert position, or raising her tail over her back, especially when these body language indicators are specific to the baby’s presence or proximity and are associated with other changes in her focus or demeanor, we have cause for concern. Other more obvious signs include growling or piloerection (the dog’s hackles go up.) Even a dog who is avoidant of the baby, choosing to move away whenever the baby is nearby, may have aggression potential in future moments when the dog perceives that her opportunity to escape from the baby is blocked or impaired in some way. Either anxious or potential predatory behavior may be exhibited in the form of intense watching of the baby, startling or quick movements in response to the baby’s cries or movements, barking at the baby, or engaging in more nipping or herding behavior toward other targets while the baby is around. In any of these cases, behavioral intervention should be arranged.

A cat who is uncomfortable around a baby may be more likely to avoid the baby altogether than a dog would, and may even hide completely for some time after the baby has arrived. Of greater concern is the cat who spends time around the baby but with aggressive body language that might include pupil dilation, tail thumping, skin rippling or twitching, and/or whiskers forward and extended. A cat who is otherwise tolerant of petting by her owners but who becomes easily agitated or aggressive while petted when the baby is nearby may be displacing tension caused by the baby’s presence onto her caregivers.


If your dog or cat shows any signs of tension, fear, or aggression toward your baby, of course your first step is to securely separate the animal from the baby and seek out the services of a CAAB or vet behaviorist. Your behaviorist will assess the situation in detail and provide individualized treatment recommendations. In many cases, when it is deemed safe to have the baby and animal in the same space, the behaviorist will recommend a systematic desensitization program for fearful animals. In these cases, the behaviorist and owner work together to create a series of steps allowing graduated exposure while providing continuous access to positive and relaxing stimuli for the animal. For example, we might work with the pet behind a gate in the kitchen and the baby with another adult in the living room, providing the pet’s favorite toys, treats, and massage while the baby is in sight or sound of the pet. Only when the pet shows reliable and sustained calm demeanor at this level would we move, for example, to having the animal on leash with one owner while a second adult is with the baby in the same room. Details of these behavior plans are developed on a case by case basis, with safety for the baby always the first priority.

In cases where the animal continues to show predatory interest in the baby (that is, he or she perceives the baby as a critter to be chased or attacked), rehoming is often the only safe and practical outcome for many families. In cases where nonpredatory aggressive responding persists even after appropriate behavioral intervention, the animal behaviorist works with the family to determine long-term safe management options and coaches the family through choices that may have to include muzzling, physical separation, or rehoming. Such choices, while necessary for the safety of the baby, are emotionally devastating for many families, and ongoing coaching and guidance from an animal behaviorist can be key in helping the family work through this difficult situation.