This might be a silly question, but are they poisonous?? And do they bite when messed with?? I noticed that it didn't want to let go of the leaf and stick when I was looking at it. Then I had it on a paper towel, and it didn't want to let go of it either. I was afraid to mess with it too much because I didn't know what it would do to me.

These are harmless as Ryan has mentioned. They tend to cling to leaves or other objects because they can can offer up very little defense against birds or other predators that would consider them a delicacy, and just don't want to be taken away and eaten!

The Smokies region has some very large tulip trees, so it would not be unusual to find a lot of these caterpillars in the area.

Ross makes a good point, larvae of Callosamia angulifera are not commonly seen because they are most commonly way up in tall tulip trees (unlike the other two species in the genus which utilize [usually] smaller host plants).

Callosamia angulifera is not poisonous as far as anyone knows, certainly no problems will come of simple contact, like most caterpillars however, I would suggest against ingesting under most circumstances.

This species will neither sting nor bite.

Thank you. I was in the Great Smoky Mountains National Park today and one of the kids found it. I haven't seen one like this before and didn't have any luck trying to figure it out on my own.