American Dagger Moth Caterpillar

The other day as I was walking down the street in Chicago, I saw a big bright caterpillar making its way across the sidewalk. This critter is an American Dagger Moth (Acronicta americana) caterpillar. It looks soft and fuzzy, but those "hairs" will sting you if you pick it up! They release toxins when they break off, a nice little defense mechanism. The caterpillar will get lighter in color as it gets older, and will turn into a moth as an adult.