What runs but never walks, has a mouth but never talks?

How to think about it

1. Each clue is a body word used in a non-body way. Collect the ways we say “run” about things that are not alive: engines run, noses run, water runs.
2. Add the mouth. Caves, jars and bottles have mouths, and so does something made of running water.
3. The longer version of the riddle mentions a bed that it never sleeps in, which narrows it to one answer.
4. A river runs, has a mouth where it meets the sea, and lies in a riverbed.

Why “a river” is the answer

A river runs downhill, empties through its mouth, rests in a riverbed and starts at its head, yet it never walks, talks or sleeps. Every clue is a word that English borrowed from the body and gave to geography. That is why the riddle feels like a creature at first and turns out to be a place.

Common wrong answers

• A nose. A nose runs and sits near a mouth, but the nose itself has no mouth, and this is a joke answer.
• A car. An engine runs, but cars have no mouth, bed or head in ordinary speech.