Texas law imposes a duty on the person who "owns, keeps or harbors" an animal to use reasonable care to prevent the animal causing injury to anyone. In addition, if the animal has demonstrated aggressiveness before, or if it is classified as a "wild animal" the owner or handler may by "negligent per se" (i.e. automatically liable) if the animal injures someone. This means that unless you were tormenting the dog or other animal in any way, the owner or keeper may be liable for any damages that you might incur. That means that he or she is not only responsible for medical bills, but for lost earnings, future damages, and pain and suffering.