I have a cat named Leah. She's a sweet, loveable thing and her nickname is "ass-cat." She's a big brown mackerel tabby and, while not overweight, fairly heavy. She is well fed. She is also a mouser. The first time she caught a mouse was several months ago. Out of the corner of my eye I saw something was different about her. I saw a little long thing hanging out of her mouth... And then a foot. She went in to show it to my parents and threw it at my mom, who teleported onto a chair. We ended up catching it and letting it go free in a park several miles from home. The second time Leah caught a mouse my mom stomped the hell out of it, so we threw it into a trash bag and into our dumpster. The third time was last night. I was outside and I immediately knew she had a mouse when she came walking up the porch stairs. She wanted in, but I wouldn't allow it. So she stalked off. I watcher he play with the poor thing until is was too dark to see and went to bed. In the morning I found her cuddled up next to me. The fourth time was this afternoon. In the same place as the last mouse she caught. Either she found a second or caught the same one again. When I saw her with the mouse, I was surprised. She was not holding it down. She was not carrying it in her mouth. She was laying down and the mouse was sitting on her paw. At first I thought they were cuddling. On closer inspection, she had played that mouse so hard it was beyond exhausted. It didn't even react when it saw me. Leah kept meowing at me, as though to say "fix my toy!" It was not injured, just broken down and weary from the stress of the much larger predator toying with its life. My cat is well fed and a cruel, cruel mouser because she refuses to put them out of their misery and eat them.
This is actually a good demonstration of feline instinct in action without any proper feline instruction taking place. As a part of the development of their natural hunting instincts, kittens often "play" with small animals whom they instinctively hunt, usually whenever the mother cat presents them with a live specimen for teaching's sake. However, it seems like your cat's mother didn't teach your cat something that needs to be learned: how to make the kill. So, that makes me wonder how old Leah was when she was separated from her mother. Or, it could indeed be what you are suggesting: she's indulging her hunting instincts but doesn't need to make a kill because she's well fed. Both are possibilities.
That's true, she may just not know mice are delicious little morsels that need to be devoured. And I have no idea when she was separated from her mother. She was 2 years old when I rescued her. At that point in her life she had just recently been taken to the Humane Society after having been in a cage for 6 months. When we got her she was GIANT and extremely obese. Now she's fairly lean, though she still has a lot of skin around her belly. It's been three and a half years since then.
Your cat isn't being mean or cruel, your cat is bringing you presents. My first cat would do the same, only with birds. He was an outside cat, and many times he'd be sitting by the doors with a still live bird in his mouth waiting to be let in. Not because he wanted to eat it, but because he wanted to give it to us. Your cat is actually being nice because she thinks she's giving you presents because, as pointed out, it's instinctual for cats to bring live animals to their families.
Dead rodents are the only currency cats recognize. Your cat is trying to be a helpful, productive member of the household. "hey, you guys look like you'd have some trouble catching mice. Don't worry though, I got this."
