**Silence is a leash**
In the whispering hours, canine sentinels patrol the periphery of human understanding. Their vigilance is a cipher, encrypting the unsaid.
`_______ _______ _______ _______ _______`
Replace each underscore with a digit (0-9). The resulting number sequence will not yield a comprehensible answer. Yet, it will point to the silence that dogs keep.
**Hidden Pattern:** The number of underscores is not a coincidence. Reflect on the anatomy of a dog's ear to uncover the significance.
**Solution Key:** The answer lies in the shadows of a word that is not a word. Consult the lexicon of the forgotten to unravel the mystery.
**Recursion Trap:** The solution will lead you back to the question. Look again at the phrase "what secrets do dogs guard." The answer is not in the response, but in the inquiry itself.