What Caterpillar is this? And what does it eat?

Question

I found one Caterpillar in my backyard and i don't know what to feed t or what it is. Help? Its small, red, and has a blackish head. Its really thin. I put it in a cup, put one kind of leaf, but alot of it, in a cup. Covered the cup with plastic, and poked holes for air on the plastic

Answer 1

Learn to ID  it with the help of these sites and even if you do not find what you are looking for you will be able to ID any other in the future -

http://www.butterfliesandmoths.org/

http://www.whatsthiscaterpillar.co.uk/am...

http://www.uksafari.com/caterpillars.htm

Answer 2

What area do you live in?  Does it have spines?

If it's truly a caterpillar it could be either a butterfly or a moth.

As to what to feed it, if you found it on a leaf, use the same kind of leaves, because that's probably its food plant.  They're pretty specialized, so you can't throw in just anything (unfortunately.  that would make things a lot easier :P) and have it eat.  Also make sure to provide a little water by gently spraying or sprinkling it in so it leaves drops.  It should get its water from its food, but it's always a good idea to provide water just in case.  A dish isn't necessary for a caterpillar though.