What did the Romans use rhyton for?

A rhyton is a roughly conical container from which fluids were intended to be drunk or to be poured in some ceremony such as libation, or merely at table. They are typically formed in the shape of an animal's head. Many have an opening at the bottom through which the liquid fell; others did not, and were merely used as drinking cups, with the characteristic that they could not usually be set down on a surface without spilling their contents.