The Monarch Butterfly

 

The Monarch is unique among butterflies in that it is the only species of butterfly that does not hibernate, but migrates in changing seasons. It undergoes four changes in form (metamorphoses) during its lifetime: 

Monarchs live for about 9 months, but they don't always look like butterflies. The monarch begins its life as an egg.   In the second stage it becomes a black, yellow and white striped caterpillar (larva). During this stage, the caterpillar sheds its skin (molts) up to four times as it grows to its full length of about two inches.  In its third stage, the monarch forms a protective covering called a chrysalis, or pupa. This  pupa is shiny and green with gold speckles.   In its final stage,  the monarch emerges from the pupa as a beautiful black and orange butterfly. 

This entire process takes about a month. There are usually three to four generations of monarchs produced each year. 

The eggs, layed on milkweed leaves, hatch into caterpillars. The baby caterpillars eat the milkweed, and grow very quickly. The milkweed contains a poison that the monarchs use as a defense. While the poison doesn't hurt the monarchs, it makes them taste bad to birds and other predators. Predators soon learn to avoid the bright colors of the monarch caterpillars and butterflies.