Max the Canine Shield
Osmar Persisco of Garibaldi, Brazil, took his dog Max out for exercise in a field and was approached by two robbers who demanded his car keys. When Persisco declined, they shot him, grazing the man's head. That's when Max went into action, jumping up to attack the two men. One ran away immediately, the other shot Max twice in the chest and once in the leg before fleeing himself. Persisco rushed his protector to the vet, where Max was successfully treated for his injuries.
The first dogs were self-domesticated wolves which, at least 12,000 years ago, became attracted to the first sites of permanent human habitation.