Whither the Rattus norvegicus?
It’s a natural question, to wonder if Frankenstorm that swamped New York City on Monday night might depart with some silver-lined clouds—namely, that Hurricane Sandy either drowned the city’s inestimable millions of hearty Norway rats or washed them off the island altogether.
Even Brooklyn’s own Bob Sullivan, author of the widely renowned book Rats, who has spent as much time thinking about rats as anyone who doesn’t pick up trash could possibly be expected to; even he had to stop and ponder it for a second:
“Well, the streets do seem a lot cleaner, in some places,” he told The Daily Beast on Tuesday.
But the rodent expert quickly came to his senses. There’s a reason rats are so often compared to humans (like a “rat in a cage”)—they’re resilient, like we are. And there’s also a reason for the myriad water-related rat metaphors in the vernacular (“rats fleeing a sinking ship”): they’re particularly good swimmers.
“They’re going to be like us,” Sullivan said. “Get washed out, try to come back in.”
People keep asking him about the tunnels, he said, hoping maybe rats will get sucked out of the city via the Holland Tunnel, for example. But that’s based on the assumption that tunnels are full of rats—a misperception, Sullivan said.
“People think where it’s dark, they can’t see anything, there are rats there,” he said. “But the number-one thing rats want to be around is people, people who drop garbage on the ground.”
Sure, Sandy caused rat casualties: drowning, getting crushed by floating taxicabs. But most of the rodents will just relocate, said Rick Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Middlebrook, N.Y.
“People and rats together have a corner on the adaptability market,” Ostfeld told The Daily Beast. “We’re amazingly resilient when it comes to these kinds of disasters, and so are our furry little friends. They just do it differently than we do.”
That’s in part because of rats’ somewhat uncanny ability to swim. They’re not particularly built for it, Ostfeld notes, with no webbed feet or muskrat-flat tail to be used as a side-to-side propulsion instrument, and they’re mostly a terrestrial mammal. But, like humans, they’re jacks-of-all-trades.
“They have an all-purpose body design,” Ostfeld said. “They’re pretty good at climbing, swimming, and running around on land.”
Animals truly threatened by a hurricane are “specialists,” Ostfeld said, leading long, slow-paced lives. Were New York full of otters, bobcats, foxes, and coyotes, there might be massive die-offs from an intense flood. Rats, on the other hand, “Live fast, die young, breed explosively, and fill up the world with more rats.”
Sandy may actually help the vermin spread diseases, as a matter of fact. It’s a fair wager that most rat populations are skittering around with one or more nasty ailments: leptospirosis, typhus, salmonella, or hantavirus, to name a few. But they don’t carry all of those diseases at once, and those pathogens and viruses are often concentrated among certain populations. What a flood can do is scatter rats (and their food: garbage), relocating them and allowing them to distribute their particular plagues to other rats and, by extension, to people.
“People and rats together have a corner on the adaptability market,” says disease ecologist Rick Ostfeld.
There are badger populations in the United Kingdom, for example, that represent the main source of tuberculosis bacteria that have proven a scourge in the cattle industry there. “If there’s tuberculosis in the cows, European badgers are usually the main source of infection,” Ostfeld said.
Farmers have in the past tried hunting those badgers to knock back the threat, only to find that it causes them to disperse and transmit the disease to a wider population. Same with some of the deadly viruses bats harbor, especially the large breed known as “flying foxes.” Past attempts to disrupt their populations has led to outbreaks of viral diseases in people and horses in Australia.
So, sorry, New York, but Sandy isn’t likely to have put much of a dent in the city’s rat problem. If anything, the hurricane may have made things worse.