Because a dog can inflict severe injury and death, a potentially dangerous or vicious dog can be ordered destroyed or its owner ordered to keep it under very strict conditions.
The meaning of "dangerous" and "vicious"
The problem with statistics
Breeds considered the most dangerous
Serial and rampage attacks
A propensity to attack other dogs means a dog is dangerous to people
Other ways that dogs can be considered dangerous
A dog attack danger scale to keep you and your kids safe
Attacks that resulted in serious injuries but not death
Regulation of dangerous dogs
Criminal penalties for owners of dangerous dogs
Dealing with a dangerous dog as a public nuisance
Differences between animal control orders and judicial orders