A wounded animal can be killed during a struggle. Animals wounded in struggles can later bleed out and die.
At the start of a struggle with a wolf, the hud will present the options the player has for defending, which depend on the tools the player has in the inventory. Struggles with wolves are won and lost based upon how quickly the left mouse button can be clicked. Whether you succeed or not, the player will lose some condition and can suffer from torn clothing or an affliction.
A struggle with a bear will always result in a loss, because the player is unable to take any action during this time and the player will stumble away with only 10% condition remaining and two afflictions.