Living with the Unwanted: The Ecology of 'Pests' and People
- Samuel Evangelista
- Sep 26
- 9 min read
by Samuel Evangelista
WTA Labs resident biologist
Modern cities are more than concrete, steel, and glass. They are living mosaics of humans, infrastructure, and non-human organisms that adapt to the rhythms of urban life. Where people build, other species follow. Ecologists call these organisms synanthropes—species that thrive in environments altered by humans. Unlike wildlife that retreats to forests or mountains, synanthropes make their homes in our homes. To study synanthropes is to glimpse the ecological undercurrents of city life, the ways in which living systems respond to neglect, crowding, and human excess. In doing so, we also uncover the invisible feedback loops between urban planning, public health, and biodiversity.
The familiar strangers
In the Philippines, these creatures are more commonly known by a less scientific name: pests. The label is telling, for it reduces them to intrusions on comfort rather than participants in shared ecologies. Rats are perhaps the most familiar. On rainy nights, you can see them swimming through the floodwaters of an estero, their slick bodies carving small wakes among the floating plastic cups and sachets. They thrive where our garbage piles high and our drains choke.
Cockroaches come next, darting through sari-sari stores, flattening themselves against the corners of kitchen cupboards. They move with such confidence it feels as though we live in their homes. The more we spray, the tougher they seem to become.
Then there are the maya birds, once tied to the rhythm of rice harvests. Today, they crowd the wires above jeepney terminals and peck at crumbs in school canteens, turning the noise of traffic into their new soundscape.
And always, there are weeds, plants that colonize disturbed environments, often characterized by rapid growth, high reproductive output, and the ability to thrive in marginal or degraded habitats. They push through the cracks in sidewalks, claim abandoned lots, and line the edges of railroad tracks. Even where concrete tries to suffocate the earth, some stubborn green appears.
To call something a pest is to place it outside the circle of belonging. It is a declaration of disgust, a shorthand for “unwanted.” But what if these creatures were not invaders so much as messengers? What if their presence told us something about the state of our cities, something we would rather not hear? To live with synanthropes is to learn from them. If we listen closely, they might tell us how sick or how our urban homes truly are.
The invention of the urban “pest”
Our uneasy relationship with synanthropes did not appear out of nowhere. It has a history: shaped by colonial governance, modernization projects, and shifting cultural imaginations. To understand why we treat them only as pests, we need to remember how our cities learned to fear and suppress them.
During the Spanish colonial period, limpieza carried meanings that went beyond everyday hygiene. In Spain, the idea of limpieza de sangre (purity of blood) was a racialized marker of status, and while in the Philippines this concept softened, it still tied notions of “cleanliness” to social order and hierarchy. Within Manila, order and discipline were most visible inside Intramuros, where sanitation and regulated space projected Spanish civility. By contrast, the farther districts were often described in official and clerical reports as crowded, unsanitary, and difficult to control. Poor drainage and waste meant rats, mosquitoes, and other pests were more common there, which reinforced elite perceptions of these neighborhoods as disorderly and dangerous. While pests were certainly a biological reality, their presence also fed into a broader language of exclusion: “unclean” spaces and “unclean” peoples became linked in the colonial imagination, making hygiene and pest control as much about power as about health.
When the Americans took over Manila in the early 1900s, they brought with them a more modern vocabulary of “public health.” Cholera and plague outbreaks pushed the new colonial government to organize sanitation campaigns. Squads drained esteros, fumigated homes, and hunted rats, presenting the animals as enemies in a war for modernity. Synanthropes became entangled in a narrative where to conquer them was to prove the city’s progress. Posters and public notices told residents to keep their homes pest-free, equating good citizenship with extermination.
After World War II, the reconstruction of Manila and the rise of mass urban migration created new conditions. Informal settlements expanded near rivers, canals, and vacant lots, places where synanthropes also flourished. Here, “pests” became a language of blame. When garbage piled up or flooding worsened, authorities often pointed fingers at the urban poor as if rats and cockroaches multiplied, not because of systemic neglect, but because of their existence . The unwanted animals were used to mark certain communities as unwanted too.
Even today, this history lingers. Pest-control ads promise “total eradication,” suggesting that a good home is one where all signs of other life are erased. Weeds in vacant lots are seen as shameful neglect, not potential green space. Stray dogs and cats are treated as hazards rather than as living beings shaped by the absence of animal welfare systems. Our cultural memory of synanthropes remains bound to disgust, stigma, and the fantasy of total control.
Yet folklore tells a different story. Rats sneak into language as insults and metaphors: parang daga for the timid, rat-rat as the sound of gunfire. Cockroaches are the butt of nervous jokes, imagined as the last survivors after the apocalypse. On the surface, these images reinforce our disgust, casting the creatures as villains or nuisances. But even in these unflattering metaphors, there is a grudging recognition of their power to endure what we cannot. To call the cockroach indestructible is, unintentionally, to acknowledge its resilience. To compare the timid to a rat is to recognize the animal’s instinct for survival in dangerous places. Stray dogs, once dismissed as askal, have been reclaimed as aspin, symbols of resilience, loyalty, and quiet defiance. Even the humble maya bird, once known as the “poor man’s bird,” sings in the memories of childhood afternoons and harvest-time fields. Folklore may curse these creatures, but it also reveals a complicated respect for their stubbornness, their ability to carve life out of difficulty. Our stories carry both revulsion and admiration, mirroring our own uneasy dance with survival in the city.
We carry these animals in our stories, proverbs, and playground jokes because they have always lived beside us. To hate them is also to hate the parts of ourselves that have learned to adapt, endure, and laugh in the face of hardship.
How pests survive where cities fail
Imagine the city as a living body. Its streets are veins, its rivers the arteries, its buildings its organs, its people the pulse. Synanthropes, then, are the fevers and rashes that signal when something is unwell. Left unchecked, they can indeed cause harm. Yet their outbreaks do not arise from their existence alone, but from the conditions we create. They are both vectors and verdicts, carrying disease while also revealing the sickness of the city itself. To see them only as threats is to miss the larger diagnosis: it is neglect, not just nature, that breeds epidemics.
In Metro Manila, this diagnosis is impossible to miss. Over 13 million people are packed into just 600 square kilometers, a density that leaves little room for silence or for solitude. Rats surface with every flood, feeding on garbage long uncollected. Cockroaches scatter across mall food courts, drawn to the dampness of centralized air-conditioning. Maya birds perch on tangled electric wires because trees are scarce. Stray cats circle karinderyas, scavenging what spills onto the pavement. Even weeds grow defiantly through concrete, reclaiming the land we have neglected.
It would be tempting to call these plants and animals inconveniences. But to look closely is to see inequality mapped in wings and whiskers. Rats and cockroaches multiply fastest in informal settlements where waste collection is erratic, flooding is constant, and houses made from thin plywood cannot keep them out. Synanthropes flourish in the city’s neglected spaces, which are most often the spaces of the poor. Wealthier enclaves, with their fumigation contracts and fortified condominiums, may postpone the encounter, but not forever. The cockroach still finds its way into the polished bathroom. The rat scurries across the underground parking lot, and sometimes even rides the elevator, slipping unseen between floors. The weed cracks open the sidewalk of a gated subdivision. Concrete can only delay the truth that our cities are porous and shared.
Yet what unsettles us most is not only their being but their persistence. In their strategies for survival, we can glimpse ourselves. Rats navigate labyrinths of pipes and drains the same way the urban poor navigate broken infrastructures and bureaucratic barriers. Cockroaches subsist on scraps, much as countless families scrape by on what the economy leaves behind. Weeds force their way through cracks, echoing the ingenuity of communities who build homes from discarded wood and tin. Maya birds adapt to terminals and rooftops just as street vendors adapt to sidewalks, turning transitory space into livelihood.
Perhaps we dislike these creatures not only because they invade our spaces but because they remind us, uncomfortably, of our own condition. They are mirrors of our resilience, our creativity, and our refusal to disappear in a city that often seems designed to erase us. In this sense, synanthropes also reveal something political: just as we call certain plants and animals “pests” when they survive outside the plans we have made, so too are many urban communities treated as nuisances by those at the top of the social ladder. Informal settlers, street vendors, and other marginalized groups are often displaced, silenced, or swept aside, managed as though they were infestations rather than fellow citizens. To name a creature a pest is to mark it as expendable. To treat people the same way is to betray how unevenly the right to belong in the city is distributed.
From eradication to reimagination
Our instinct is to eradicate. We poison, trap, fumigate, sweep, and pave over. Yet extermination rarely lasts. The rat returns with the garbage. The cockroach with the dampness. The weed with the forgotten soil.
The harder and more necessary task is reimagination. How do we design cities that prevent pest outbreaks by addressing root causes, not just symptoms? One starting point is waste management. More regular and reliable garbage collection, supported by local governments, reduces the resources these animals depend on. Neighborhood-level composting projects can turn biodegradable waste into fertilizer while cutting down what attracts vermin. These solutions aren’t glamorous, but they are cheaper and more sustainable than endless fumigation.
Another step is green space planning. Birds and insects gravitate to electric wires and concrete cracks because there are few alternatives. Introducing pocket parks, pocket forests, and community gardens can redirect wildlife into designated habitats. This doesn’t eliminate synanthropes altogether, but it creates buffers. Urban greening also cools down neighborhoods and absorbs floodwater, addressing problems that benefit people as much as animals.
When it comes to stray animals, humane population management is both more ethical and more effective than mass culling. Spay-neuter programs, supported by Non-government organizations and city veterinarians, reduce stray numbers over time while preventing the cycle of abandonment and overbreeding. Feeding bans or cruelty campaigns do little without parallel investments in shelters, clinics, and adoption networks.
Infrastructure also matters. Flood management, drainage repair, and housing upgrades directly reduce the breeding sites of pests like mosquitoes and cockroaches. Informal settlements, often neglected by city services, bear the brunt of infestations precisely because water and waste systems are weakest there. Addressing these deficits is not only a matter of fairness but of public health.
Of course, these solutions are easier said than done. Budgets are tight, and political priorities often sideline basic services in favor of high-visibility projects. Still, each of these strategies is more realistic than the fantasy of “total eradication.” Synanthropes will never fully disappear from our cities, but their numbers and impacts can be managed if we treat them as indicators of where the city is failing.
To reimagine is not to romanticize. It is to accept that the category of “pest” and that of “synanthrope” are not opposites but overlapping truths. One describes the immediate disruption to comfort, the other the ecological role that disruption points toward. To call something a pest is to name our frustration; to call it a synanthrope is to widen the lens and recognize the conditions that gave it space to thrive. The movement between these terms is less a contradiction than a rhythm, a kind of uneasy dance that reminds us how our judgments are entangled with the environments we have built. Reimagination begins when we learn to listen to both beats at once.
Living with the unwanted
To live with synanthropes is not to glorify them. It is to accept them as reminders. They are signals of what is broken and proof of how life persists in spite of our neglect. They are not just a nuisance but a compass.
The unwanted are here because we made room for them, whether through neglect or carelessness. To kill them without listening is to continue the cycle. To listen is to turn them into unlikely guides, showing us the way toward healthier cities.
The true pest is not the rat or the cockroach. The deeper infestation is our poverty of imagination. The real nuisance is not the weed or the stray dog, but the absence of compassion in the spaces we design.
Cities are not machines we operate nor fortresses we can seal. They are living bodies, porous and shared, pulsing with human and non-human lives. Synanthropes, despised as pests, are the whispers of this body. They tell us when something is unwell.
To live with the unwanted, then, is to recognize that the city does not belong to us alone. The smallest creatures mark its pulse, its memory, its diagnosis. We may not welcome them, but we cannot erase them without listening. For in their stubborn survival lies a question we cannot escape: What kind of city have we built, if these are the ones that thrive?
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