In states that do not have strict liability "dog-bite laws," in order to recover damages from the animal's owner an injured person usually must show that the owner knew (or had reason to know) that the animal was predisposed to bite or attack -- that the animal had what is known as "vicious propensities."

The following list describes some of the more common factors that can be used to demonstrate an owner knew or should have known of his or her animal's vicious propensities. Keep in mind that this is not a complete list, and simply proving one of the items below does not guarantee a legal victory.

Breed and Size of Animal: Generally, the larger the animal, the greater the chance that the animal can cause injury. The species and breed of an animal may also be relevant if you can prove that, as a general rule, that breed has a propensity for viciousness (such as a pit bull or Rottweiler).

Purpose for Which the Animal is Kept: If an animal is kept for protection, and is trained to attack unknown people, it can be inferred that its owner knew or should have known it might attack someone.

Frequent Snapping and Biting: A history of aggressive behavior can be used to demonstrate that the owner had knowledge of the animal's vicious propensities.

Complaints Brought to Owner's Attention: If people previously complained to the owner, and the owner did nothing (or didn't do enough) to prevent future attacks, this can be used as evidence that the owner knew the animal could be dangerous.

Fighting with Other Animals: Even if an animal had not attacked a human before, if it had fought with other animals, this may be useful in proving its vicious nature.

Frequent Confinement of the Animal: If the owner keeps the animal locked in a cage, or on a tight leash or chain, this may indicate the owner's awareness that the animal might be dangerous.

Occasional Muzzling of the Animal: Particularly with respect to dogs, if an owner muzzles an animal on walks or at times when people are near the animal, this can be proof that the owner is aware of the animal's dangerous nature.

Warning Sign on Owner's Premises: If an animal owner puts up warning signs (such as "Beware of Dog"), an injured person can use this fact to establish the owner's knowledge of the animal's viciousness.

Statements by Owner as to Animal's Character: Any statements made by the animal's owner concerning past bites, fights, or aggressive behavior are relevant to the owner's knowledge regarding the likelihood of future attacks.

Owner's Warnings to Strangers About Animal: Verbal warnings to others potentially show that an owner is worried that the animal might cause harm to others.

In preparing to meet with an attorney regarding an animal bite or attack, consider all of the above factors and speak to people in the community where the animal lives to learn more about the animal's past. These steps might help to strengthen your case significantly.