Really great game that I have plugged countless hours in. Designed by Will Wright, published by Maxis and released in 1991 for PC/mac 1992 for Amiga and 1993 for SNES.
In it you take control of an ant and perform various tasks such as locating food and digging tunnels. You can kill the evil spider that snacks on your fellow ants if you build up a strike force or you can take a small force and turn that caterpillar into a snack.
You can control the percentage of each type of ant being born; workers which are good for well working, soldiers which are good for fighting and breeders which are used to make new colonies. You can also control what percentage of your ants are foraging, digging or nursing. Or you can just leave it on auto. When your energy is running low you need to eat a piece of food or another ant can nourish you.
You can recruit some or all of your ants and lead them to food or to battle. For the SNES version there was a campaign mode and a yard mode where the ultimate goal was to take over the entire yard and inside of the house and drive out the evil human who is always stepping on you and mowing down your fellow ants. In the campaign there are specific goals set and when you meat them it will advance to the next stage. Whereas in the yard mode the goal is to buildup a large enough colony to support breeders then colonize new sectors and repeat until you control all sectors. Impeding your progress are the spiders, the human and your true rival the red ants.
Anyway its a different kind of game and I got a lot of enjoyment out of it.