Laura never names what she is describing. Nowhere in "the city is alive" do the words train, car, skyscraper or ship appear. Every piece of urban machinery has been swapped for a creature, and the reader has to decode them. The "silvery snakes" that "slither through holes in the ground" read as underground trains, with the "shrieks" as screeching brakes and the "tiny insects" crawling from their "sterile insides" as passengers. The "long-necked monsters who claw at the sky" are towers. The "shiny metal snails" creeping along a "black track" dotted with "white streaks" suggest cars on a marked road, and the "iron whales" are ships. The title announces the central idea and the last stanza confirms it: the city is not just full of machines, it is a living organism, and a predatory one.
The stanzas work like a tour through different habitats: the burrows underground, the canopy of skyscrapers, the road, the open sea. By the end we have crossed a whole ecosystem, so the final claim feels earned rather than simply declared.
People get little room in this ecosystem. The only trace of them is the "tiny insects" that "scuttle to and fro under the shadows" of the towers. They are small, hurried and interchangeable, and they live in the shade of bigger things. The word "sterile" is quietly clever. It means clean, but it also means barren, a place where nothing can grow. The poem seems to ask what kind of life a city has when it is built from "metal" and "iron" and keeps its living beings so small.
Though the poem has no rhyme and no regular beat, its sound patterns do a great deal of work. The opening line hisses with sibilance ("Silvery snakes slither"), and "Sly and silent" keeps the hush going until "Shrieks" breaks it, so the creature that seemed stealthy turns out to scream. "Creep slowly" and "slippery slime" drag the snails along at their own pace, while "Bloated and buckled" has heavy, clumsy b-sounds, like hulls wallowing in water. The repeated "Upon the sea… / Upon the rocking waves" gives the whale stanza a swaying motion. "Monstrous" appears twice, first for the whales and then for their roars, and the repetition works like a drumbeat that makes the threat feel hard to escape.
The most telling image comes in the smoke. The smog and fumes "Curl up to the clouds like a giant, toxic octopus," and "toxic" is the poem's one openly critical word. A few lines later, "a fat plume of smoke / Shakes hands with the sky." The handshake is friendly and polite, and that is the irony. It sounds like two parties agreeing a deal, with pollution welcomed into the heavens. "Fat" also suggests something well fed, which prepares us for the ending.
In the last stanza the animal disguises start to fall away, leaving "hungry mouths" and "ferocious claws," body parts with no bodies attached. It is also the longest stanza, five lines where the others have four, as if the poem cannot wrap itself up neatly. The tone turns flat and matter-of-fact: the mouths and claws "wait to attack / Like all wild animals do." Until now the creatures have been busy, slithering, creeping and sailing. Now they are waiting, and that stillness is more unsettling. The calm final line also treats the danger as natural, as though a city that preys on us were no more surprising than a lion in a savannah. The poem never says who the prey is, but the tiny insects of the second stanza are the obvious candidates.
What makes the poem worth reading is how it makes the familiar strange. Trains, traffic and tower blocks are things most of us stop noticing, and here they become a bestiary we can't ignore. The poem doesn't lecture or argue. It builds one extended metaphor and lets the unease build until the last line. It is one-sided, since nothing in it suggests what the city gives back, but that narrowness gives it focus. By the end it is hard to look at a passing train without seeing a snake.