When I was an intern at the Philippine General Hospital (PGH), my blockmates and I sometimes saw giant rats scurrying across the hospital, sometimes even transgressing the sterility of the OR, to the horror of our nurses and residents. Dubbed “roborats” at the time because of their seemingly monstrous form, urban legend has it that they feed on placentas, antibiotics, and other materia medica to make them the mutants they’re believed to be.
As attested to by current PGH interns and clerks—“They’re all over the wards,” says Gap Gutay of Class 2026; “They’re indestructible!,” adds Josh Siscar of Class 2025. The rats, now simply called “PGH rats,” are still around—and they’re far from being the only rodents in town. Like all urban centers around the world, Metro Manila is teeming with members of genus Rattus, including the invasive brown rat (Rattus norvegicus), which can grow up to over 800g. Earlier this year, a video clip of a large rat scampering in the ceiling of Ninoy Aquino International Airport Terminal 3 went viral and prompted public outrage.
And while we might be tempted to think of the rats—especially in airports and hospitals—as a national embarrassment, it is important to emphasize that this is a global phenomenon. In New York City, there are an estimated 3 million rats; such is the attention to rats in the Big Apple that there’s been a newly appointed “rat czar” while there are also newly developed “rat tours.” Last year, Tokyo officials begged residents of a district in Shinjuku to stop feeding rats, vowing to exterminate them.
Scholars agree that rats have had a long history as urban inhabitants, participating in various human journeys as a “commensal” species (i.e. getting food and shelter from us without giving anything in return). The brown rat, for instance, is theorized to have originated from Northeast Asia (not in Norway as its scientific name suggests), reaching Europe via the Mongol Invasion and the rest of the world via regional trade routes and colonialism. Astoundingly, none of the domesticated urban rats we know today had reached the Americas prior to 1492, and in Southeast Asia itself, the arrival is estimated to have taken place in the 1200s (see Puckett and Munshi-South, 2019).
Just as old as this history are the problems associated with rodents, from consuming food and contaminating products to damaging structures and spreading diseases. Today, all of these problems remain relevant, and rodents are especially notorious in public health as carriers of leptospirosis (even as it must be emphasized that anthropogenic factors—e.g. lack of urban housing or flood control—that make particular groups of humans vulnerable to the disease.)
Given such negative associations, it is understandable that humans have long tried to exterminate rats, beyond those who were tricked by the Pied Piper of Hamelin (cats—which also abound in PGH, as Gutay reminds me, are for another essay). As Ambeth Ocampo wrote in a recent column (“Rats among us,” 09/06/24), anti-rat campaigns in the early 20th century were “so lucrative that someone harvested many tails from a Tondo rat farm… In 1906, Filipinos were paid 50 cents for every rat presented for extermination.” In a fascinating account, the historian Patricio Abinales (2012) wrote of how rats also figured in our postwar politics, from senators calling for an “all-out war” to Marcos conscripting the AFP to join his anti-rat campaigns.
Obviously, such campaigns have not had a significant effect; Abinales wryly concludes that “the Philippines—as in other places—the rodents continue to have the upper hand despite having been pushed out of the public discourse.” Indeed, moving forward, it is clear that rats will continue to be around us, and beyond any eradication campaign, any effective and sustainable response will have to consider the urban areas as an ecosystem, and act on the predisposing factors—e.g. unmitigated floods that make the rats harmful to humans.
Meanwhile, scientists—while acknowledging the risks posed by rats—urge a nuanced view of their kind. For one, rodents have advanced medical science more than any other of our “companion species” by literally being the “laboratory rats” that have enabled the development of vaccines, drugs, and various lifesaving technologies. Also, they’ve been the victims of false accusations—like being blamed for bubonic plague. And while it’s mostly been invasive rat species that have plagued our cities, endemic rodents contribute to our mammalian biodiversity, and indeed one of the most magical moments of my hiking journey was seeing a giant cloud rat (Phloeomys pallidus) in one of Mt. Pulag’s lesser-trodden trails.
As for the filth they’re associated with, scientists also remind us they are largely of our making, from our leftover food (over 2,000 tons every day, as per the Philippine Institute for Development Studies) to our garbage (over 8,000 tons a day), and so if anything, rats are mere symptoms of human disorganization and urban decay.
“It is us, the humans,” as rodentologist Bobby Corigan was quoted in a National Geographic article as saying. “We don’t keep our nest clean.”
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pdlasco@up.edu.ph