Toby Burke threw himself between his wife Laura, his three children and the wild animal.
The 48-year-old, who was on a bird watching trip in Kenai Peninsula in Alaska, then stood his ground as the bear dove towards him.
‘It was just me between my family and the bear,’ he said.
At first Mr Burke defended himself with his camera tripod but this proved fruitless as the huge animal snapped it in half.
The bear then bit his arm, which sparked him into action – and he proceeded to punch the female brown bear in the face several times.
After a short while the beast decided it had had enough and ran away.
Mr Burke and his family all escaped unharmed but the bear, which was aged around 20, had to be shot dead after it later attacked police officers.