Cat In The Bag

With domestic cats, males are more likely to fight than females. With feral cats, the most common reason for cat fighting is when two males are competing to mate with a female: most fights will be won by the heavier male. Another possible reason for fighting in domestic cats is when the cats have difficulties in establishing a territory within a small home. Female cats will also fight over territory or to defend their kittens. Spaying females and neutering males will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked to sex hormones.
When fighting, cats make themselves appear more impressive and threatening by raising their fur and arching their backs, thus increasing their apparent size. Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. Attacks usually comprise powerful slaps to the face and body with the forepaws as well as bites, but serious damage is rare; usually the loser runs away with little more than a few scratches to the face, and sometimes the ears. Cats will also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.
Normally, serious injuries from fighting will be limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission of feline immunodeficiency virus (FIV). Sexually active males will usually be involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to the ears and nose.