Appears to be Actias luna caterpillar, larva of the Luna Moth.

Unless, of course, this caterpillar is very small....but that doesn't appear to be the case.

Thanks ever so much Rhizo..I will pass along your info. This caterpillar was close to 3" long. Wasn't in my yard where every other caterpillar/insect/evildoer resides..hope ms.luna behaves her/himself!

The luna caterpillars don't travel in packs and aren't considered a pest even though their job is to eat foliage. They feed on a small list of deciduous woodland hardwoods like hickory, birch, sweetgum, etc.

I hope that your friend leaves this rather reclusive guy to go about its business. If roaming around, it's probably looking for a suitable place to pupate.

Luna moths are one of the most elegant and beautiful of native insects.

HERE are some pictures.

Apparently Ms. Luna has been moved to a sidegarden/shrubbery area with red twig dogwood/crabapple/ and some ninebark that have been rather neglected. Good cover for her, I hope she/he stays within sight..I'd love to see her awakening!

We're inundated recently with insect life we've not seen this far north or south, and with the super heat back for a repeat of summer, things seem to be misplaced. I'm the only one hoping for a deep freeze winter..too many leafthoppers/grasshoppers/moths that lay green larvae that destroyed my 50 ft hops/japanese beetles, and now Luna Moth larvae..even though there's likely to be little impact from Luna! The rest..move on!