Biggest caterpillar I've ever seen in my life. I nearly yelped when I spotted it. It was 5.5in (14cm) long. Grab a ruler and see how long that really is!
It is an atlas moth caterpillar. In June, I had posted a shot of one, but it was much smaller. Because this caterpillar was unusually big, I was able to get fairly good shots of its legs.
All caterpillars have 6 true legs, which are the legs it retains through pupation and which transform into the legs of a butterfly. These 3 pairs of true legs end in claws, and you can see them clearly in the bottom shot, where they are near the head of the caterpillar.
The other legs are called prolegs. They are used for walking, climbing and attaching the caterpillar to branches and other surfaces. You can see the close-ups of the prolegs in the top right shot. (Please view large for the exciting details! ;D )
I was able to observe how the caterpillar moved, and was fascinated to see that the blue parts retracted under the black bases of the prolegs when the legs moved. These blue parts (called distal planta) are extended when the caterpillar stopped moving. You can see in my shot that the tiny hooks on one of these blue parts have sliced into the branch! That makes an awesome grip!
Mr Caterpillar ate an entire leaf that was as long as itself in 10 minutes. It gnawed all the way down to the main branch so that, when he was finished, no trace of the leaf was left, it was as if it had never existed. Then he went to sleep. XD
PS. How do I know he was 5.5in (14cm) long? No, I don't walk around with a ruler in my bag. I'd placed my hand next to Mr Caterpillar (but I made sure not to touch him or disturb him) and made a mental note of where he'd started and ended on my hand. When I got home, I placed my hand next to a ruler to get the actual dimensions. 8)
This caterpillar will become this beautiful atlas moth, which is the largest species of moth in the world in terms of wing surface area: http://www.factzoo.com/insects/atlas-moth-worlds-largest-moth-never-eats.html