(In reply to answer
by K Sengupta)
Since the referred to person/object can run but is unable to walk, it is clear that we are looking either for an inanimate object or a natural phenomenon or natural formation or manifestation of a natural phenomenon.
The word "run" in conjunction with "bed", "head" and "mouth" suggests "river" as a possible answer to the riddle.
This is corroborated in terms of the following definitions:
Definition: RiverMouth is the subclass of WaterAreas that are the outfalls of a river or stream into another body of water
Definition (i): The area between the banks of a river ordinarily covered by water
Definition (ii): A channel occupied (or formerly occupied) by a river
Definition (iii): The passage where the river flows is called the riverbed
Definition: The source of a river.
In view of the foregoing, it is now clear that the required answer to the riddle is "River".
Edited on April 18, 2008, 7:12 am