Chapter One Rats
(RATTUS NORVEGICUS)
I’ve spent most of my life working with animals. I love them. Well, most of them. I am not fond of rats. Most people aren’t. But I admire these invasive rodents because they have managed to invade every continent on Earth except for Antarctica. In fact, as you read this, I bet there is one lurking nearby.
Liverpool, England, 1772
Hundreds of ships are anchored offshore or tied to docks at one of the busiest seaports in the world. Merchant ships, scows, warships, skiffs, and schooners dot the murky gray water. Along the shoreline are hotels, taverns, shops, warehouses, restaurants, shipyards, shipping offices, horse-drawn wagons, and thousands of people plying their trade, which is trade. What Britain manufactures and grows is shipped, sold, and traded to other countries. What Britain can’t grow or manufacture is shipped in from other countries. If you travel to Britain, or travel to another country from Britain, you must board a ship.
Tied to the dock, ready to sail, is a 150-foot merchant ship, which for our purposes we’ll call the Augusta, but it could be any ship in 1772 from any number of countries. It is bound for New York, 3,471 nautical miles across the Atlantic Ocean. On board are tons of cargo, a ship’s captain and officers, forty sailors, ten passengers, and fifty brown rats, commonly known as “Norwegian rats.”
Rats love wooden ships. The storage areas, living quarters, and cargo holds belowdecks are dark and dank with hundreds of places for rats to hide and build nests. There is plenty of food for rats to eat aboard, and they don’t have to travel far to reach it. On land, rats rarely venture more than 300 feet from their nests to find food, which makes a ship an ideal place for them to live.
During Augusta’s five-week voyage, the rats thrived, reproduced, and multiplied. When the ship docked in New York, there were over 200 rats living on it. The passengers and crew disembarked; the cargo was unloaded. The rats had no choice but to disembark because there was no food in their wooden home. They climbed down the thick mooring ropes in the dark of night, skittering across the wharf into alleyways and the basements of buildings. There were a few black rats (also an invasive species) already in the alleys and buildings, but they were no match for the larger and more aggressive brown rats. The black rats that were not killed outright were outcompeted for food and chased from their nests.
The brown rats quickly learned how to avoid the 30,000 people living in the city. There was a lot of garbage in the streets, plenty for the rats to eat. Within a few weeks there were 400 brown rats in New York City. Within a few years there were 500,000 thousand brown rats.
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The Norwegian rat (although it is not originally from Norway) is also called the brown rat, common rat, street rat, sewer rat, wharf rat, Parisian rat, Hanover rat. In 1769, it was given its scientific name by the British naturalist John Berkenhout who believed brown rats had arrived in England on Norwegian ships in 1729. The brown rat probably did arrive aboard ships, but long before 1729, and not just on Norwegian ships. The brown rat was native to northern China and spread throughout the world on visiting ships from several different countries.
Rats hang out near people because people have garbage, and rats love leftovers. Like us, rats are omnivores. Scientists have done studies on what rats like to eat. Among their favorite foods are scrambled eggs, macaroni and cheese, raw carrots, and cooked corn kernels. Their least-liked foods are raw beets, peaches, and raw celery. But this doesn’t mean that rats are picky eaters. When a rat is hungry, it will eat whatever food it can sniff out.
There are 150 million to 175 million rats in the United States, which is roughly 1 rat for every 2 people. Rats don’t live much beyond 3 years. And 95 percent die during their first year. If that’s the case, why are billions of them still skittering around the world? Babies. Let’s do the math. Rats can reproduce when they’re 5 weeks old and can have 5 to 6 litters a year with 6 to 8 pups in each litter. This means that a single female can produce up to 48 babies a year, or 144 babies in her lifetime. If 5 percent of these live to be 3 years old (half of these pups will be females), those rats will produce over 500 babies in their lifetime, and on and on.
Rats eat our garbage. What’s not to like about that? Unfortunately, rats eat our fresh food supplies as well as our garbage. Because of their voracious appetite, it’s estimated that rats destroy about 42 million tons of food around the world every year. In the U.S. alone, the economic cost of rat damage is estimated to be $19 billion a year.
Rats also carry and spread disease. Among the diseases are: hantavirus pulmonary syndrome, hemorrhagic fever with renal syndrome, Lassa fever, leptospirosis, lymphocytic choriomeningitis, Omsk hemorrhagic fever, rat-bite fever, salmonellosis, and the bubonic plague. You can’t write about rats without writing about this plague, or the Black Death as it was called in the 14th century, which killed 50 million people in Europe, Africa, and Asia. That wasn’t the first outbreak of the plague, and it wasn’t the last, but it was the worst. The disease is not caused by rats but by Yersinia pestis, a bacillus that lives inside certain fleas. If an infected flea jumps from a rat to a human and bites them, they may contract the plague and in turn pass it on to other humans by merely coughing on them. In 1350, there were no medications to treat the plague. The plague still lurks in fleas that live on rats, mice, and other rodents, but it’s been hundreds of years since the plague has spread to become an epidemic—or a pandemic. There are 7 to 14 reported cases of plague a year in the U.S., and 1,000 to 2,000 worldwide.
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When rats aren’t eating, they are gnawing. Rats have to gnaw because their front teeth grow throughout their short lives. If they don’t gnaw, their incisors could grow as much as 5 inches a year. If a rat doesn’t keep its incisors gnawed down, it can’t eat and it will starve.
Rats gnaw on just about everything: walls, floors, doors, appliance components, furniture, plumbing, gas lines, cables, and electrical wires. If your cable goes out, it could be a rat. If your house catches fire, it could be from a rat chewing the protective insulation off the wires in your walls.
If a rat can’t get into your house for shelter, it might take up residence in your family car. A car is dry, relatively warm, and has plenty of things to gnaw on, or to eat if the car isn’t vacuumed out frequently. The eco-friendly wire covering used in many newer cars today is like candy to rats: Instead of being made out of plastic, the covering is made out of soybeans.
Speaking of gnawing and teeth, I should say something about rats biting people, which is rare but does happen. Around 100 rat bites are reported in the U.S. every year. It’s thought that there are more rat bites than that, but people are reluctant to admit that their child has been bitten by a rat. I say “child” because most rat-bite victims are children. Most of the bites occur at night while kids are sleeping. Rats target exposed fingers, toes, and faces. Horrible, I know, but the chances of this happening to you, or anyone you know, are just about zero.
People bite rats more often than rats bite people, because people eat rats. Rat meat is eaten in many countries around the world. One reason for this is because rats are plentiful and generally easy to come by, so they make a good source of protein. I’ve probably eaten rats myself, although unknowingly. A few years ago, I spent a couple of weeks working with Asian elephants in Myanmar (previously called Burma) doing research for a book. The nearest restaurant or grocery store was 100 miles away. The oozies (elephant handlers) ate what they could find in the forest. Every night they kindly cooked a meal for me in charcoal-heated woks. The food was good, but they refused to tell me exactly what the mystery meat was. They simply smiled and called it “camp meat.” Rat meat is sold in open markets in China. In the Philippines you can buy canned rat meat in grocery stores under the brand name STAR, which is RATS spelled backward.
As much damage as rats have caused in towns and cities around the world, the havoc they have wreaked on tropical island ecosystems is far worse. Rats arrived on islands the same way they arrived in mainland countries: on ships.
Black rats, Pacific rats, and our old friend the brown rat have invaded nearly every island on earth, eating bird eggs and chicks, turtle eggs and hatchlings, plants, seeds, trees, snails, crabs, reptiles, amphibians, and anything else they can ingest for nourishment. Some rats have even been known to catch and eat live fish. Their need for food has devastated these delicate island ecosystems and led, directly or indirectly, to the extinction of several island plants and animals.
WHAT ARE WE DOING ABOUT THE RAT PROBLEM?
I can usually tell if a city has a rat infestation by visiting a local grocery store. I don’t look at the tiled floors for rats scurrying down the aisles, I look up at the signs: Laundry Detergent, Bread, Spices, Dairy … Rat Snap Traps. Just kidding, rat traps are never advertised. You have to find the section yourself. It’s usually next to sponges, mops, bug spray, fly strips, and cockroach traps. How big the section is depends on how big the rat problem is in the area, and this fluctuates from year to year. Even though rat traps are readily available, I think people are reluctant to buy them because they get embarrassed by the purchase at checkout. Flour, butter, eggs, sugar … I guess you’re baking something. Oh, I guess you have rats … No one should be uncomfortable buying rat traps. Chances are your neighbor has rats too—in fact, the rats you have may have migrated from your neighbor’s house to your house.
Snap traps work, but they are not the best way to get rid of rats. Rats usually travel along familiar tracks, rarely deviating, and they are leery about anything new or unusual on their pathways. More often than not they’ll walk around the trap even if it has been baited with something they like. The snap trap was invented by a British ironmonger named James Henry Atkinson, in 1897. He nicknamed his mousetrap “the little nipper.” A rat trap is bigger because rats are seven times larger than mice. I guess that means the rat trap is “the big nipper.” There have been variations on Atkinson’s design over the years in an attempt to build a better mousetrap, but all snap traps work pretty much the same way. You put a bit of food on the trip plate, pull back the hammer, set the holding bar into the catch, and place the trap along the rat’s pathway, careful not to trap your fingers when you set the trap down.
Poison has been the most effective way to get rid of rats, but there are downsides to that. Most rat poisons are put into bait boxes designed specifically to attract rats. Unfortunately, other animals can get into the boxes as well, eat the poison, and die. Predators that eat rats can die from eating poisoned rats. Another problem is that a poisoned rat doesn’t die right away. If it lives in your home, it might die inside a wall where you can’t reach its body to remove it. Rats don’t smell good when they’re alive and their smell doesn’t improve upon death, at least not for a few weeks.
A relatively new way to kill rats is with dry ice. It’s inexpensive and safe for non-targeted animals unless they’re living in the burrow with the rat. The process is pretty simple. You find a rat burrow, shovel some dry ice into the opening, follow the dry ice mist to the second opening (rats always have a back door), block that opening, and then the rats suffocate from carbon monoxide poisoning.
Rats are social creatures. They live in groups. If you see a single rat, you can bet it’s not alone. If you see a rat in the daytime there’s probably a rat infestation. Rats are nocturnal. They don’t usually risk daytime appearances unless the competition for food is too great at night.
Large rat infestations are taken care of by city exterminators or privately contracted exterminators. These are the men and women on the front lines fighting the unwinnable rat wars. All they can hope for is to reduce the population enough to control it. Everyone can join the fight, though, by keeping garbage in rat-proof containers, and preventing rats from taking up residence in houses and buildings. If you take away a rat’s food and shelter it will move away.
I realize that I’ve been a little rough on rats, but this doesn’t diminish my admiration for them. Rats are smart and adaptable. That’s why they are so successful in so many ecosystems. They didn’t decide to invade the earth like a bunch of triffids. They just jumped aboard ships looking for food and shelter, and then disembarked all over the world, and took advantage of what they found in new lands.
According to Orkin, one of the oldest exterminator companies in the U.S. (established in 1901), the following are the rattiest cities in the U.S. If your city or town is not named here, don’t worry, you have rats too.
The Rattiest Cities in the U.S.
ChicagoNew YorkLos AngelesSan Francisco–OaklandWashington, DCPhiladelphiaDetroitBaltimoreSeattle–TacomaDallas–Fort WorthDenverMinneapolis–Saint PaulCleveland–AkronAtlantaBostonHartford–New HavenPortland, ORMiami–Fort LauderdaleIndianapolisHoustonMilwaukeePittsburghNew OrleansCincinnatiRichmond–PetersburgSacramento–StocktonKansas CityCharlotteNorfolk–Portsmouth –Newport NewsBuffaloColumbus, OHSt. LouisRaleigh–DurhamGrand Rapids– KalamazooSan DiegoAlbany– SchenectadySan AntonioTampa–Saint PetersburgRochester, NYNashvilleChampaign–Springfield –DecaturGreenville–SpartanburgMemphisPhoenixSyracuseWest Palm BeachOrlando–Daytona BeachMadisonFlint–SaginawGreen Bay–Appleton
Chapter Two Birds of a Feather Invade Together
EUROPEAN STARLING
(STURNUS VULGARIS)
Nay, I’ll have a starling shall be taught to speak
Nothing but “Mortimer,” and give it him
To keep his anger still in motion.
—Henry IV, Part 1, William Shakespeare
In this scene, Hotspur, a sworn enemy of the king, is fantasizing about teaching a starling to say “Mortimer” (the name of another enemy of the king) over and over again to irritate the king. European starlings are fabulous mimics. The composer Mozart bought a starling that learned to sing part of one of his piano concertos. He was very fond of the little bird. When it died after three years, he held an elaborate funeral for it, and wrote a poem for the ceremony, which begins:
Here rests a bird called Starling,
A foolish little Darling.
He was still in his prime
Text copyright © 2023 by Roland Smith
Illustrations copyright © 2023 by Gavin Scott
