Every other Friday on Morning Edition, the Outside/In team answers a question from a listener about the natural world.
This week, one of Outside/In’s Instagram followers asked, “What makes an animal a pest?"
Whether we’re talking ants, cockroaches, mice or mosquitoes, just about everybody has encountered a pest problem at some point in their lives. But what makes an animal a pest? Is it an entirely subjective and situational label? Or is there some sort of scientific determination we use to categorize nuisance animals?
To find out, I reached out to Bethany Brookshire, science journalist and author of the book “Pests: How Humans Create Animal Villains.”
She points out that various dictionary definitions will essentially tell you that a pest is an animal or plant that bothers people in some way. But that’s not the whole story.
“What pests are is a reflection of us,” Brookshire says. “They're a reflection of what we want and what we believe about our environments. And that goes for people who research them as well as people who just happen to live in a city full of rats. We expect animals to be in their place. But who determines what an animal's place is? We do.”
Here are two examples that help to illustrate Brookshire’s point.
Example 1: From pet to pest in 100 years
Once upon a time, humans loved pigeons. They were our most common domesticated birds. The news company Reuters was started on the back of carrier pigeons used to fly stock prices quickly across long distances. Pigeon waste was a bountiful source of fertilizer, and the birds themselves were a common source of food. (Pigeon meat is called “squab.”)
But over the course of about a century, all of those useful traits were made obsolete by new technologies and alternatives, and nowadays pigeons are viewed by many as a nuisance.
Brookshire points to a study by Colin Jerolmack that tracked mentions of pigeons in the New York Times from 1851 to 2006.
“They go from starting as innocent, beautiful, naive, charming, to rats with wings,” she says. “And it was only a hundred years.”
Example 2: A snake with two faces
In Southern and Southeast Asia, the Burmese python is listed as “vulnerable” — not quite endangered, but dangerously close. Hunting and habitat loss have shrunk its range and reduced its population by roughly half in the past twenty years.
In places like Vietnam, and Southern China, this gigantic snake is the subject of conservation efforts. But in the Florida Everglades, Brookshire says, they’re targeted for eradication.
There, Brookshire says, the view is that “Burmese pythons are invasive and evil and need to leave so badly that every year there is an organized hunt where they send hundreds of dudes (mostly dudes) out into the Everglades in trucks coated in floodlights, trying to catch pythons and kill them.”
To be clear, she says: There’s little difference between the species being targeted in Florida, and the ones being protected elsewhere. “They're just in different places,” she says. “And in one place we feel pity for them and in another we cannot get out our machetes fast enough.”
A pest by any other name
There are other examples in Brookshire’s book. House cats have managed to largely avoid being labeled as pests, despite having contributed to the extinction of at least 63 species and counting. Mice, deer, certain types of insects — all of these are considered friends or foes depending on the situation.
Ultimately, I asked Brookshire: Is there any animal that is universally seen as a pest, everywhere in the world?
“No,” she said. “Not even rats. There is, for example, a temple in India where the black rat is worshiped because they are believed to be the reincarnations of a specific family of the goddess Karni Mata.”
But then, after a moment’s thought, she reconsidered.
“Pretty sure there's nobody out there who's chill with bedbugs,” she said. “So that's probably a good one.”
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