Answer:
What can be heard and caught but never seen?
Only two backbones and thousands of ribs.
I am never quite what I appear to be. Straight-forward I seem, but it's only skin deep. For mystery most often lies beneath my simple speech. Sharpen your wits, open your eyes, look beyond my exteriors, read me backwards, forwards, upside down. Think and answer the question...
What runs around all day. Then lies under the bed. With its tongue hanging out?
I fly through the air on small feathered wings, seeking out life and destroying all things.
I fly to any foreign parts assisted by my spreading wings. My body holds an hundred hearts Nay I will tell you stranger things when I am not in haste I ride and then I mend my pace anon.