You go to leave for the day and find that Kitty has left you a present on the stoop: a dead mouse. This is not the kind of present you hoped to receive. While dead animals certainly wouldn't go over well at Christmas, your furry pal meant well.
No matter how domesticated our friendly felines have become, the desire to hunt has never diminished. Even the most well-fed house cat will chase after a dangled piece of yarn or catnip-infused plaything. Kitty is a carnivore, he has to eat meat to survive. He depends on nutrients he gets from animal proteins. Many of the activities you view as simply play are mock-hunting to your little guy. You may see him as your fluffy little buddy chirping happily at the birds out the window; he thinks he's a lion stalking his prey.
Your home isn't just a cozy place for Kitty to cuddle, it's his lair. Kitty presents you with his trophy kill, be it a mouse, lizard or maybe a snake, because he's bringing home the kill to his family. This is a natural behavior for him, so don't make the mistake of screaming or yelling at Kitty. Give him some love and appreciate the gesture, then carefully dispose of the unwanted gift. If the animal is still alive, let it go outside. Depending on what Kitty decided to hunt, you may have to call animal control to properly resolve the mess.
You're Not a Good Hunter
You probably don't hunt for your food, unless you consider tackling the local mega-mart hunting. Kitty sees this as a problem he can help with. His mother cat would bring home prey for him and his siblings. He wants to help you out by bringing you a fresh kill to enjoy. Kitty views you as another cat, so he'll often display the same behavior he would to other cats. While the upside is that he snuggles and grooms you, the downside is he may think you want a dead animal, too. The most likely to do this are spayed females, since their maternal instinct will kick in. Try and take it with a grain of salt and remember, like with all unwanted gifts, it's the thought that counts.
Curbing the Behavior
The best way to prevent Kitty from littering your home with animal carcasses is to keep him indoors. This is all-around safer for him anyway, since outdoors he's more likely to get diseases, injuries or infested with fleas. Get him a collar with a bell. Kitty can stalk his prey all he wants, but they'll hear him coming and escape before he can catch them.
Make sure he's well fed. A full tummy won't stop him from hunting, but he'll be less likely to do it if it's only for play and not for a meal. If he's a solitary feline, think about getting him a buddy. Two kitties will often practice hunting by chasing each other around instead of the small critters in your yard.