Instinct is a built-in need to do something. It's not something an animal thinks about; it's something it does automatically. A baby bird automatically throws its head back, opens its mouth wide, and screams for food. It is an instinct. Baby bats automatically cling to the cave wall. Grasshoppers naturally spit out the things in their stomach on predators that try to eat them. Bees naturally work to take care of the hive and make honey. Butterflies inherit preferences for laying their eggs on certain plants.plant their young need to eat, and that's where they lay their eggs. Animals are born with these instincts, and they follow their instincts without conscious thought.