A butterfly begins life as a tiny egg. The adult female places her eggs carefully on a leaf, usually on a plant that her young will be able to eat. A few days later, a small, hungry caterpillar comes out of each egg. The caterpillar's only job is to eat and grow. It eats the plant's leaves almost all day and all night.
After a few weeks, the caterpillar stops eating and finds a safe place. It then builds a hard shell around itself called a chrysalis. From the outside, it looks like nothing is happening. Inside, however, a remarkable change is taking place. The body of the caterpillar slowly turns into the body of a butterfly, with wings, long legs and antennae.
When the change is complete, the butterfly breaks out of the chrysalis. At first its wings are soft and wet, so it must rest until they become dry and strong. Then it flies off to find flowers. Butterflies drink a sweet liquid called nectar from the flowers, and as they move from one flower to another, they help the plants to make seeds.
Most butterflies only live for a few weeks, but some kinds live for months.