Dogs that bite and attack without warning make headlines. The story is often the same — people trusted the dog so much that they left it alone with a child.
But a lot of the time there were warning signs that were minimized, ignored or unrecognized. Most trainers would have clearly spotted the telltale warnings.
However, there are also pets that legitimately surprise owners with a sudden burst of rage and aggression. Any trainer with an ounce of honesty will tell you that dogs can turn violent without warning.
This happens because many aggressive dogs are actually ill. Studies have shown that more than 50 per cent of dogs with behaviour problems have an undiagnosed medical condition that causes them to bite impulsively, giving very little warning.
New research by Tomas Camps of the Autonomous University of Barcelona in Spain, published in the April issue of the Journal of Veterinary Behavior, may shed some light on the matter.
Camps’ team found that friendly dogs respond to pain differently than animals with a history of aggression. Friendly dogs react impulsively, meaning that they bite without giving warnings such as growls.
There are a couple of plausible explanations. Owners of aggressive dogs are likely cautious in their daily interactions with the pet. With caution comes less contact. On the other hand, owners of friendly pets assume the animal is happy, healthy and tolerant. Their trust in the dog leads to more contact. But uninhibited contact could cause pain to the animal triggering a bite.
Alternatively, aggressive dogs may have learned how to use minimal levels of force to communicate discomfort. They know how to back people away without inflicting damage while normally-friendly dogs may not have learned how to say, “Back off that hurts,” with any level of restraint.
What should owners be on the lookout for?
• Behaviour changes are commonly an early warning sign of pain. Owners should be on the lookout for aggression, vocalization, accidents and changes in activity level or social interaction.
• Schedule a yearly physical at the veterinarian to catch health issues early. Skin and knee problems are two common ailments associated with pain. The most common illness is hip dysplasia, an abnormal formation of the hip socket. While common in large breeds of dogs such as goldens, labs, Rottweilers and German shepherds, toy breeds like pugs are often afflicted. With some breeds, more than 40 per cent of dogs develop hip dysplasia. Nor is it limited to elderly animals. Young puppies can show symptoms, but because both symptoms and pain levels can vary, the disease can be difficult to diagnose. Watch for changes in the dog’s movement or gait. Affected dogs often have a run that looks similar to a bunny hop.
Understand too that not all dogs respond to pain in a predictable manner. While some snap unexpectedly at being touched, others growl when disturbed in their sleep or chewing a bone. Pain often results in sleep deprivation and that in turn can lead to irritability.
The Camps study underscores the importance of ruling out medical conditions before jumping to behaviour-based conclusions. But you should still take reasonable safety precautions and model appropriate behaviour for children. Do not ever take your friendly dog for granted if it is not used to being with kids.
Yvette Van Veen is an animal behaviour consultant. Write her at firstname.lastname@example.org