Our class pets are 5 caterpillars who are turning into butterflies! First, they started as eggs. Then, they started to hatch in to caterpillars. They change and grow into pupas. A caterpillar needs to eat a lot of grow. The caterpillar sheds its skin. The caterpillar grows new skin under its old skin! Many animals like to eat caterpillars. Caterpillars make a nice treat for a spider, wasp or bird. After about 3 weeks the pupas splits open and then they are butterflies.