Why is it eating pipevine? (aka Southwestern Pipevine)
Could it be the Pipevine Swallowtail caterpillar? In fact, it is. I was in the canyon today with my own personal photographer and spouse, Matt Ball; instead of getting a photo of the pipevine 'flower' (which Carol and I saw on Tuesday), he 'shot' this great critter - not quite an inch long, red and moist looking, with some amazing protuberances.