A bear that can never drink enough, a cat that recovers only halfway, a whale that is already dead: the creatures in Mary F. C. Pratt's poem are all in some kind of need, and for most of the poem the woman who dreams them is the one who looks after them. Only in the last stanza does the pattern break. She stops tending the creatures and becomes one of them.
The opening stanza sets the tone with an odd mix of the homely and the wild. She is "polishing brass, or cooking supper" when a bear appears at her window. She responds as a good host would, filling a tub and carrying it through "the flimsy door." The word "flimsy" matters. Everything about her kindness is small-scale: a tub for a bear, bones and cream for a half-dead cat. The line "The bear would drink and drink, never enough" ends on a flat, weary note, because the offering will never match the need. The second stanza goes further. The cat she rescues staggers off "meowing from one side of its mouth, / blinking its one green eye." Her care works, but only partly, and the poem lets that partial success stand without comment.
The third stanza takes the dreams out into open space. A dead whale washes up on a "shingle beach," its flesh "draped loose like blankets tossed." The simile is the most domestic image in the poem, and it makes the huge carcass look like an unmade bed. She walks "through the lipless mouth / into that rib-walled room," so the body becomes a house, but an empty one. Even the one living presence, Jonah, is "asleep," and the stanza ends bluntly: "Every other time, she was alone." The poem doesn't explain why the dreams are lonely, but the sequence suggests that giving help, however generous, has left her isolated.
The form matches this. The poem is in free verse with no rhyme scheme, and its stanzas run six, six, seven and seven lines, so the last two have room to expand. The first three stanzas use habitual verbs ("She'd fill," "would wash up"), which make the dreams feel like a repeating routine. Then comes "But one night, a living whale swam through," and the tense changes to a single, particular event. The sound of the language changes too. The earlier stanzas are plain and practical, with words like "brass," "tub" and "bones." The last stanza becomes more musical and strange: "luminous," "sapphire," "flukes," and the long, rolling "All night long she swam."
That final stanza is the poem's turning point. The whale is alive, and a woman rides on its back. The dreamer "knew the rider," which hints that the rider is herself, and then she feels "blood heat / of her own muscled arms, great flukes." The pronouns blur so that rider and whale become one. "In vision" also lifts the experience above an ordinary dream, and the sapphire, the only jewel in the poem, gives it a blue, watery rarity. The word "unmaimed" answers the one-eyed, lopsided cat of the second stanza, because here nothing is damaged or half-repaired. The closing phrase, "one creature, her long thirst quenched," picks up the bear's unsatisfied drinking. Reading the poem as a whole, the thirst seems to have been hers all along, and the bear was carrying it for her.
The title, "Once, Leviathan," ties this together. Leviathan is a sea monster from the Bible, and the word suggests something enormous and untameable, the opposite of the tub-sized kindness of the opening. "Once" echoes the poem's own "Once" in the second and third stanzas and also the fairy-tale opening "once upon a time." It hints that this fulfilment was a single event, perhaps never repeated.
The poem's significance lies in how it works. It never says what the woman wants or why she is alone. It lets a sequence of images do that, moving from small domestic acts to the open sea, and from giving to having. A reader can take it as a poem about caring for others at the cost of oneself, or about finding a larger, wilder self. Either way, the final image is physical and complete, a body at home in the water.