The new skin forms the chrysalis that covers the caterpillar's body. When the skin hardens, it takes on a green color. The color helps the chrysalis blend in with vegetation, which makes it less noticeable to passing birds and other predators.

Why are some chrysalis green and some brown?

Dr. Neal writes: “The color triggers or inhibits the release of a hormone that controls pupal coloration. High levels of hormone will produce a brown pupa, low levels produce a green pupa.

How long does chrysalis stay green?

A monarch chrysalis is light green with a series of shimmering, golden dots on the outside. From a distance, this chrysalis could be confused with a shiny, under-ripe fruit, but the monarch chrysalis doesn't stay green for long. After around 10 to 14 days, its green color fades, and the chrysalis becomes transparent.