Little black boxes became prominent figures on Pomona College’s campus prior to the start of classes this semester. Deployed in the name of pest control and found all over campus grounds, they are injecting poisons into the urban ecosystem of Claremont and are threatening countless species that share our home in Southern California. These boxes might only be slightly larger than a textbook, but they are part of a biocidal war waged against rodents. This systematic poisoning must stop if Pomona’s campus is to be sustainable.
These black bait boxes can be found on the ground alongside the walls of academic buildings, dining halls and dorms. They contain a poison called diphacinone that is meant to kill rats as a form of pest control. Diphacinone, an anticoagulant, leads to excessive bleeding and prevents clotting. When animals, like rats, consume the rodenticide, they bleed to death internally.
This poison kills rats and serves its purpose of reducing rodent populations, but its unintended consequences outweigh the benefits: Anticoagulants like diphacinone do not kill animals immediately. Poisoned rats can survive up to two weeks before they ultimately succumb to the lethal toxin.
While the rodent is living on borrowed time — and even after it dies — diphacinone is still active: The poison still has the capacity to kill. If a predator like a hawk, coyote or bobcat consumes a rat that has anticoagulants in its system, the toxins move their way into that wild animal and the broader ecosystem. In fact, diphacinone has been found in mountain lions living in Southern California, as well as in their fetal cubs.
Every time a predator eats a rat tainted with poison, poison is transferred to that predator — a process called biomagnification. Biomagnification occurs when concentrations of contaminants build up in predators that consume repeated doses of chemicals and accumulate more toxins in their bodies than their prey can sustain.
This is the very phenomenon Rachel Carson discussed and campaigned against in her book “Silent Spring,” which chronicled the dangers of superfluous chemical use and has become nearly synonymous with environmentalism in the United States. The book was published 60 years ago last month, yet we are still using poisons without considering the broader environmental impacts today, even at a liberal arts college that supposedly teaches its students to think critically in all aspects of life.
After ingesting enough poison over its lifetime, predators as heavy as 200 pounds, such as mountain lions, may eventually succumb to the rodenticides themselves. Predators are found dead with detectable concentrations of the toxins in their tissues. In the time it takes for these predators to die from repeated and persistent poisoning, they may travel vast distances; think about how far and fast a hawk or owl can fly.
The poisons are carried along for the ride and enter ecosystems otherwise far removed from the Claremont Colleges. When these animals die, scavengers feed on the highly contaminated tissues and the cycle begins anew.
In terms of pest control, yes, anticoagulant poisons do succeed in killing rats. However, they also kill the species that naturally keep rodent populations in check. This not only reduces the diversity of species in the area surrounding the 5Cs but also counteracts the ultimate aim of controlling rodent populations. As rat predators die off, more and more poisons will need to be purchased to compensate for the loss of free and natural rodent control.
There are other methods of limiting rodent populations. Rodent traps use mechanical methods such as springs or pressurized pistons to instantly and humanely dispatch individual rats. These kinds of traps avoid leaching toxic chemicals into the surrounding ecosystem and refuse to prolong rodent suffering before an ultimate death.
While these traps may cost more than poisons, they are reusable and serve a higher purpose of fulfilling Pomona’s sustainability goals. Pomona wishes to “construct, operate, and maintain efficient buildings and outdoor venues to create healthy spaces and minimize environmental impact.” This is not the case when it comes to controlling rodents. How can the college be minimizing its impact on the environment when one building alone — such as the one which houses Frary — can have five or more boxes distributing poisons?
Actively poisoning the environment when viable alternatives that minimize ecological impacts are readily available is outrageously contradictory to the school’s stated goals. The school also reports that it is “emphasizing natural methods of pest and weed control instead of applying chemicals (including pesticides)” despite zealously dispensing toxic pesticides that reduce the populations of natural predators.
In “Silent Spring,” Carson says “we stand now where two roads diverge. But unlike the roads in Robert Frost’s familiar poem, they are not equally fair. The road we have long been traveling is deceptively easy, a smooth superhighway on which we progress with great speed, but at its end lies disaster. The other fork of the road — the one less traveled by — offers our last, our only chance to reach a destination that assures the preservation of the earth.”
It is crucial that students know how a “sustainable” campus like Pomona is approaching rodent control. As members of the Pomona community, we are the ones that must choose whether we will enable a leading institution to utilize toxic methods of rodent control, or if we will do better by using sustainable alternatives.
Jacob Ligorria PO ’23 is studying biology and geology, focusing on ecology and conservation. He and many others are working toward a world in which poisons no longer destroy local ecosystems and eagerly await the day Pomona decides to ban them on the school’s campus.