Where did the saying "Bite the dust" come from?

Solution 1:

"To bite the dust" means to die or to fail (see e.g. Wiktionary). Picture someone falling down, wounded or dead, quite literally biting the dust (soil, ground, earth). Etymonline says that the first recorded appearance of the phrase is from 1750. The Phrase Finder supplies it as follows:

The earliest citation of the 'bite the dust' version [of the earlier phrase 'lick the dust', from the Bible] is from 1750 by the Scottish author Tobias Smollett , in his Adventures of Gil Blas of Santillane:

"We made two of them bite the dust, and the others betake themselves to flight."

[...]

[Samuel Butler's 19th century translation of Homer's The Iliad] contains a reference to 'bite the dust' in these lines:

"Grant that my sword may pierce the shirt of Hector about his heart, and that full many of his comrades may bite the dust as they fall dying round him."

Whether that can be counted as an 8th century BC origin for 'bite the dust' is open to question and some would say that it was Butler's use of the phrase rather than Homer's.

Solution 2:

The phrase was originally applied solely to humans who, as others have noted, might literally end up with a mouthful of dirt as they fall to the ground in battle. It has since taken on a more figurative sense and can refer equally to all manner of inanimate fails:

bite the dust informal be killed : and the bad guys bite the dust with lead in their bellies.
• figurative fail; come to an end : she hoped the new program would not bite the dust for lack of funding.

I found this antedating of bite the dust from a 1728 English translation of François Fénelon's Les Aventures de Télémaque:

Solution 3:

Through laden pack beasts and shifting clouds of churned earth, two travellers can be seen locked in combat. The desert air is dry and pierced with the calls of vultures. They have been on this road too long. Another challenger has risen to vie for leadership of the clan, the fourth in so many days.

As before, the leader's experience and sheer force of will overwhelm the opponent.
A sharp crack to the face sends him reeling backwards, twisting, falling, face-first in the dirt.

"Another one bites the dust," she spits, wearied.