Do Not Disturb!
A Swallowtail caterpillar has an osmeterium present immediately behind its head. This is a gland that gets activated when the caterpillar is disturbed, which lets out a foul odor, deterring predators from eating it.
Nature is really a wonder, and it creates wonders as well. One classic example is the life cycle of butterflies. First, the egg is developed, from which a caterpillar emerges. It later transforms into a pupa, which again metamorphoses into a beautiful and colorful butterfly. The caterpillar stage is one of the most interesting life stages of the butterfly. There are many types of caterpillars in nature, out of which green caterpillars are commonly found in vegetation and gardens. Hence, they are seen in the vicinity of humans quite often. Identifying green caterpillars is easier if you observe them carefully.
Caterpillars are ravening feeders. Most of them are herbivorous and live on plants for food. They have tubular and segmented bodies. Their body shape is somewhat similar to worms. Some of the caterpillars are hairy, while some are soft and plain. With this basic knowledge, green caterpillar identification is easier.
Main Body Color
Green caterpillars are obviously green in color, but the shade differs as per each individual type. Hence, the shade of green would help you identify a caterpillar better. Again, their size may be big or they may be very small.
Main Body Pattern
You also have to see the pattern of the caterpillars' body. They can be banded, striped, dotted, slashed, or even camouflaged. The design on their body would make the identification easy.
You must also check the fuzz on the body. The hair density could be high, low, or moderate. Some of the caterpillars have unique hair growth patterns on their bodies, like tufts.
Once the primary observation is done, you must look for some unique features that would assist you in the process of precise identification of the green caterpillar that you have found. These distinguished features could be a tail or split tail, head horns, knobs, lashes, spines etc.
Once you observe the above things, carefully note them down. There are many websites that would help you in your endeavor of identifying that caterpillar. Some examples of different types of green caterpillars are given below.
Big Green Caterpillar
Luna Moth Caterpillar
Green Caterpillar with White Stripes
Pellucid Hawk Moth
Green Caterpillar with Black Spots
Green Caterpillar with Horn
Green Caterpillar with Yellow Spots
Old World Swallowtail
These were some of the green caterpillars that have distinguished features and are very easy to identify. You can refer to a caterpillar identification chart to increase your knowledge about the different types of caterpillars.