The poem starts with a riddle: what's gray and comes in quarts? The answer is "an elephant," a pun on "elephant" and "quarts" that doesn't quite work, or "my brain," which hints that the speaker feels dull and heavy-headed. From there the poem drifts. It pictures an old, slow elephant who has waited a long time to give birth, and the speaker uses her to argue for patience: "come to whatever you come to slowly."
Grayness, he says, is not just a state of mind. It belongs to the age we live and grow old in. Rushing, the poem suggests, wears things out early, aging elephants, driving bears from caves, turning leaves. Only the weather should set the climate.
The mood is wry, tired, and a little uneasy. The speaker seems to want numbers and measurements to hold onto, something solid. Yet he ends by returning to the riddle and calling it "a joke," as if even his own wisdom might be one. The tone stays half-serious, half-teasing.