The unnamed pair were pursuing a female bear weighing about 140kg when it spun around and attacked the father, according to Jonny Sjoblom, the hunt leader.
Sjoblom said the bear had pinned the older man down and lacerated his face before his son punched the bear in the head. The bear was distracted and bit the son’s wrist, giving his father time to shoot it dead, Sjoblom told TT news agency.
The incident happened on Monday in Ljusdal, a rural area of central Sweden about 290 kms north of Stockholm.
Both were taken to Umeå hospital. The father’s facial injuries are thought to be serious but not life-threatening.
This year authorities have licensed hunters to kill up to 649 bears, the largest cull in decades.