The boy suffered serious arm and back injuries when he was mauled by a Rottweiler on the seafront at Southend, Essex.
The boy was paddling on the Eastern Esplanade at about 4.15pm on Friday when a man walked past with two Rottweilers. One of the dogs grabbed hold of the child, forcing him under the water.
His grandmother pulled the animal away and the owner and the dogs ran back on to the promenade.
Pc Rob Kirk said: "The boy's grandmother had to physically pull the dog from the boy for fear it was going to drown the child or continue to bite him to death.
"It must have been a terrifying ordeal for all concerned."
The boy suffered about 20 puncture wounds to his torso and arms. He has undergone two operations and remains at Broomfield Hospital in Chelmsford.
The dog walker was black and in his 30s. He was about 6ft 4in and of slim build, with short black hair. He was wearing a blue top and jeans and is believed to live in Southend.
(Daily Mirror - August 8, 2011)
