What's going on...?
All the creatures want companionship and food, but they don't like to bump into each other.
They each have an energy level which decreases all the time. The more they move, the more energy they use. The energy is replenished when they eat, but the amount of energy they receive is random. Some meals are more filling than others.
At a certain level they become hungry. While they are not hungry, they seek companionship with the group. If they are hungry, they move faster and target the food. They don't seem to mind shoving each other out of the way to get it either!
Only one creature can eat a piece of food, after one piece of food is claimed, other hungry creatures need to target a different piece of food. If a creature goes too long without food, it dies.
Dead creatures reincarnate after about six seconds.
If you feel like confusing things you can try catching them and dragging them around. Another variation shows the bonds between the objects.
(by the way... this is just about fast enough on my 1Ghz PC - it may be slow on older machines)