I wake up not to an alarm but to the performance by a small percussionist. From the corner of the bedroom wall comes the dry, rhythmic chuck-chuck-chuck of a house gecko. A pale comma pressed against the plaster, it watches me from its hideout. Its translucent throat pulses like a second clock.

In the kitchen, a procession is already under way. Ants advance with the solemn urgency of pilgrims, each bearing crumbs lifted from my pantry. On the terrace, a pair of squirrels—grey-brown streaks of playfulness—scatter from a half-eaten tomato, scolding me for interrupting breakfast. A pigeon coos from the ledge outside, its call echoing faintly against concrete. Before the day’s human noises gather—the pressure cooker whistle, the scooter’s ignition, the street vendor hawking his goods—the house is already alive with other citizens.

Beyond and within the familiar confines of our home, a vibrant, bustling ecosystem thrives, often unnoticed but always present. Insects navigating by chemical maps, reptiles calibrated to warmth, birds following air currents. While we welcome some, such as the sparrow or the squirrel, others, such as the house gecko or the cockroach, are perceived as nuisances, challenging our sense of control and cleanliness. Yet, they all contribute to the rich tapestry of life that surrounds us, each with wondrous stories of survival and adaptation.

Consider the gecko again, that nocturnal sentinel on my wall. Long before it learned to patrol bedrooms, it was a tree-dweller. Now it has adapted to the vertical planes of buildings, clinging to our walls with remarkable dexterity. Or take the cockroach, a creature that has endured ice-age cold, drought, and poison with an indifference bordering on philosophy. It can slow its breathing to conserve moisture, slip through gaps thinner than a coin, and persist where more delicate species vanish. Elsewhere, in forests north of the Arctic Circle, the wood frog can freeze its entire body and still its heart during winter, only to thaw and resume life when spring returns.

Some species, of course, have prospered precisely because of us. The house sparrow’s long companionship with humans began thousands of years ago, when humans shifted from hunting and gathering to agriculture. Feeding on grains and seeds, the bird followed us across continents, nesting in eaves and rafters. Others—rats in granaries, pigeons in lofts—have joined this accidental fellowship. Many others have been around long before we humans came into the picture.

Yet, we tend to guard our homes from the invasion of these animals, birds, and insects. We spray bathrooms and bedrooms with sharp-scented chemicals, sanitise our surfaces, dismantle cobwebs until the presence of these creatures is eliminated or reduced greatly. But the paradox is difficult to ignore. It is our architecture, our waste, our artificial light, our carefully hoarded food that create the very niches that these creatures exploit. We created a thriving environment for them and then resent their presence.

From time immemorial, we have interacted with them, although our perception of them is a changing dynamic, from fascination, even affection, to fear and disgust. Pigeons were prized possessions of the royals and the elite up to the 19th century but are now reviled, with almost every city in the world taking steps to control their population.

The house sparrows’ story is the exact opposite: once considered a scourge, they were systematically targeted, so much so that they have now almost vanished from the planet. Their disappearance prompted an American biologist to remark: “When sparrows are rare, we tend to like them, and when they are common, we tend to hate them. Our fondness is fickle and predictable and says far more about us than them. They are just sparrows.” This statement perhaps sums up our attitude towards all non-human citizens of the world.

There was a time when our relationship with them was less adversarial. Cultures across the world folded animals and insects into myths and legends. A spider could be a devotee, a frog a symbol of fertility, a rat an emblem of abundance, an ant a sign of divine industry. These associations did not arise from sentimentality alone; they reflected an older awareness that human life was braided into a larger fabric of living forms. To notice an animal was not merely to observe it but to recognise oneself in it.

Echoes of that sensibility persist in art, pop culture, and literature. Cinema invents reptilian aliens and heroic rodents. Poetry hears romance in the hum of bees. Science studies the same beings with another kind of curiosity. Engineers watch cockroaches slip through narrow gaps to design flexible robots, prosthetic legs, and mechanical hands for humans. Frogs and rats have long been sacrificed at the altar of science, bestowing on us insights into the human condition and into how bodies heal, freeze, regenerate.

Yet the shared city is growing hotter, louder, less forgiving. As climate change ripples through our cities and forests, amphibian populations decline, insect rhythms falter. The small lives that once flourished unnoticed at the edges of our rooms now register the tremors of planetary change. Their absences, when they come, will be quieter than their presences but far more consequential.

Perhaps to live attentively is to accept that our homes are not isolated islands and our walls are not boundaries. We are participants in a shared habitation. Perhaps the faint click of a gecko in the morning is not an intrusion but a reminder that the world has never belonged to us alone.

Deepa Padmanaban is a science journalist and author of Invisible Housemates: The Secret Lives of Monkeys, Geckos, Pigeons and Other Creatures We Live With.

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