Why are some animals considered ‘pests’?

It comes down to culture and convenience

Elan Abrell, Wesleyan University

Turkey pecking at his reflection in the back of my car.
Photo by Will Collette

After wild turkeys attacked an 83-year-old woman in May 2026, sending her to the emergency room for stitches, police warned residents of Alameda, California, to avoid interacting with the animals. 

Wild turkeys can be particularly aggressive during mating season. They can also damage property: digging up gardens, staining decks with their droppings and occasionally attacking cars and windows when they mistake their own reflections for rival turkeys.

Turkeys may be a nuisance to Alameda’s human residents, but they have also been highly valued by multiple cultures throughout the history of North America. Given these threats to human safety and property, is it fair to call this quintessentially American bird a pest?

As an anthropologist who studies human-animal interactions, I have found that the idea of a “pest” is a flexible concept that changes over time and across cultures. Just as one person’s weed can be another’s wildflower, the category of pest is a subjective one that depends on social, aesthetic and economic values within a particular culture.

If Turkeys decorate American dinner tables and are pardoned by presidents, are they still pests?

Labeling an animal a pest typically justifies the use of harmful or deadly methods to remove undesirable species from human spaces. But these methods can lead to costs that far outweigh their benefits, causing unnecessary suffering for not only the so-called pests, but also for humans, other animals and entire ecosystems.

Understanding why people label certain animals pests can help society respond to potential conflicts while minimizing harm to both humans and animals.

What is a pest?

The English word “pest” comes from the Latin word “pestis,” meaning plague, instrument of death or destruction, or nuisance.

The Black Death is one of the most infamous historical examples of the link between disease and pests. This pandemic of bubonic plague spread via rodents carrying infected fleas, killing an estimated 25 million people in the 14th century in Europe. The discovery that animals carried the plague gave rise to one of the earliest pest control professions: the ratcatcher.

Some animals that humans consider pests are synanthropes: wild animals that have adapted to human habitats for the various benefits they receive from human activities. Sometimes, this adaptation is self-directed, as in the case of rodents or coyotes attracted to human food stores.

But humans often contribute more directly to the adaptation of synanthropic animals, as in the case of pigeons, one of the earliest domesticated bird species. The wild descendants of domesticated rock doves, pigeons still thrive in human environments where they can find food and nest in the clifflike edifices of buildings.

People have also contributed to the spread of nonnative or “invasive” species. Maritime travel dispersed rodents and feral pigs across countless island ecosystems. Misguided efforts at controlling other pests, in this case insects that damage sugarcane crops, led to the introduction of cane toads in Australia.

Animals out of place

Many pest animals pose no actual threats to humans or their ecosystems, but this does not stop people from seeing them as trouble.

Most species of spiders, for example, are harmless to humans and can help eliminate insects that may be even more unwelcome in a home. And despite their status as despised backyard invaders, moles actually provide benefits to gardens by aerating soil and consuming insects and mollusks that feed on plants.

Squirrels become pests when they wander where
people say they shouldn’t be. Jed T. Hoyt/Wakelee's
Pharmacies/California business ephemera collection/
California Historical Society via Flickr, CC BY

To understand why harmless animals are still often perceived as pests, you can look to anthropologist Mary Douglas’ foundational concept of matter out of place. In her 1966 book “Purity and Danger,” Douglas argues that cross-cultural concepts such as purity and pollution are based on normative ideas about the proper places for particular things.

Dirt, for example, is not a specific unclean substance, but a social category people use to describe matter that is in a place where it does not belong. Mud smeared on your clothes, skin or eating utensils, for example, might be dirt in this sense, whereas mud on the ground would just be a part of the soil where it belongs.

Pests, similarly, can be understood as animals that violate spatial boundaries determined by cultural values. For example, a deer and her fawn grazing in a meadow, or a family of squirrels nesting in a tree, might become pests if they were to start grazing on prized rosebushes or nesting in an attic.

Like plague-spreading fleas, these animals can pose real harms to humans, but the category of pest need not be tied to an objective assessment of risk.

Potential dangers of pest control

The culling of sparrows through China’s Four
Pest Campaign, which lasted from 1958 to 1962,
led to mass famine after causing ecological
imbalance. Wikimedia Commons

Designating animals as pests can sometimes do more damage than the animals themselves.

Historical efforts to control or eradicate pests illustrate both how culture influences which animals are placed in this category and the unintended consequences that can arise from putting them there.

In 1532, the Tudor Vermin Laws provided bounties for killing a broad range of species perceived as a threat in Early Modern English society to agricultural food stocks. 

These animals included badgers, bats, crows, foxes, hedgehogs, otters and owls, among many others. Vilified for superstitious or erroneous beliefs, many of these species did not actually compete with people for food or pose other significant dangers.

Four centuries later, in the mid-20th century, China’s government similarly encouraged people to eradicate over a billion sparrows to prevent them from depleting grain supplies.

These policies in England and China pushed many species to the brink of extinction, inflicting ongoing harm on ecosystems while failing to address food supply problems. 

In the case of China’s anti-sparrow campaign, a failure to recognize sparrows’ ecological role as insect predators led surviving swarms of locusts to devastate the grain crops, contributing to mass famine that killed nearly as many people as the Black Death in Europe.

Contemporary efforts at pest control have also caused unanticipated collateral damage. The pesticide DDT notoriously caused widespread harm to ecosystems while also posing a significant risk to human health. The regular use of chemical rodenticides is a danger to humans, companion animals and wildlife.

New ways of coexisting

Humans have very good reasons to be concerned about potentially harmful species. Indeed, the mosquito, one of the most common pests around the world, is also responsible for more human deaths than any other animal.

However, the category of pest has often provided an overly simple framework for targeting other animals for extermination, in many cases with serious ecological consequences.

Beyond the many harms of efforts to eradicate pests, the concept of pest itself has contributed to human violence by providing a powerful metaphor for dehumanizing marginalized groups throughout history.

Rather than denigrating other animals as pests, people can address potential dangers of other species while also taking responsibility for how we contribute to these fraught relations. Understanding pests as a subjective cultural category opens space for questioning whose interests are served by such designations, who is harmed by the label, and what possibilities for alternative relations may exist.

As in the case of Alameda’s turkeys, leaving other animals alone and finding ways to coexist may lead to better outcomes for all.

Elan Abrell, Assistant Professor of Science and Technology Studies, Wesleyan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.