Please identify this caterpillar.

Factual Questions
1

I’m sorry, but I don’t have a picture, just a description. It was gone by the time I got back out there with my camera, so I think a bird got it.

It was about an inch and a half long. It had an asymmetrical “foot” on each end, and what was in between looked exactly like a twig off a maple tree. The body was gray with subtle black striations and a slightly rough texture, just like new maple bark, and a couple of black bumps in the middle that looked like branch buds. If it helps, I only realized it was a caterpillar when I tried to pick it off the underside of my deck railing, which happens to be under an enormous maple tree.

The camoulfage was so good that I only realized something was amiss when I touched it and it moved. It was only then that that I thought, “why would a maple twig be stuck up under my deck railing?”

Any suggestions?

2

Could be a Large Maple Spanworm. Did it move by looping or inching, rather than smoothly walking along? It’s a moth, and common throughout the US.

3

It didn’t move at all until I touched it, and then it just sort of scrunched up. When I first saw it it was perfectly stiff and immobile. I assume it would inch, because there was only a foot on each end. I couldn’t tell front from back, either.