Criminal liability and civil liability are two very different things. The government prosecutes criminal cases with penalties including potential incarceration upon a conviction. A conviction requires guilt beyond a reasonable doubt.
Injured parties pursue civil cases, which do not seek—beyond awarding punitive damages in some cases—to punish the defendant, but rather to hold responsible parties financially liable for an injury. In strict liability cases, such as those involving a dog bite, the claimant does not even have to prove negligence by the defendant. Rather, the injured individual simply has to show that, based on the preponderance of the evidence, the defendant was the owner or was in control of the dog that caused the attack while the injured individual was legally on public or private property.
In addition to civil liability in a dangerous dog case, the dog owner can face a misdemeanor conviction with a penalty of up to $5,000 and imprisonment of up to five years. Subsequent convictions can result in a felony that carries a penalty of up to $10,000 and imprisonment for up to five years.