A bull-mastiff that escaped from a yard in Southern California attacked a 6-year-old boy and his mother, causing the boy to lose his ear, police said.

The incident occurred in Moreno Valley, California, on Wednesday, when the dog viciously attacked Ruben Juarez Jr. while he was walking with his mother and another sibling through their neighborhood.

The boy, whose ear was severed in the attack, had to undergo surgery to have it re-attached.

Juarez' mother also suffered bite wounds to her back when she attempted to rescue her son.

The dog, which had no history of aggressive behavior, was seized by Moreno Valley Animal Control.