Rats on the Warpath
Rats almost wiped out man once by destroying food, spreading plague. And they are still trying
IF RATS were in the habit of celebrating their victories the way men often do, there would have been a lot of thick rat heads in Calgary, Alta., one day last July. There, in a railway yard, the rat forces of the East met those of the West, bridging the world’s last no rat’s land in the manversus-rat war which began many centuries ago.
Man can no longer boast that he alone, of all t he earth’s creatures, has spread out to occupy the entiré world. With the fall of Alberta, t he last rat frontier, the rat hordes, too, can now claim that every habitable corner of the globe is t heirs.
It’s true there are many parts of interior British Columbia and southeastern Alberta which rats have not yet occupied. But when the spearheads from East and West met last summer at Calgary, they had won the last, big campaign: only moppingup operations remain.
A filthy, ravenous, flea-bitten glutton so completely domesticated that he will live only with man, the rat does more damage than all the world’s other mammal pests combined. He will eat little else except the food that we ourselves eat, and damages far more food than he act ually consumes. In Canada, for instance, it costs every man, woman
and child two dollars a year to feed some rat—for there are just about as many rats as there are people in the Dominion.
At least, there were in 1942 when the Department of Agriculture and the Department of Pensions and National Health conducted a survey which estimated our rat population at 12 million. Meanwhile U. S. Department of Agriculture investigators determined that 50 pounds of grain—or its equivalent in other food—are required to maintain one rat for one year. Canadian government biologists thus concluded that every rat eats at least one dollar’s worth of food a year and at a conservative estimate destroys as much again which he doesn’t eat.
Rats are destroying 200 million bushels of grain every year across the border, according to the U. S. Fish and Wildlife Service—more than one third of what the U. S. is planning to export for hunger relief in Western Europe and twice as much as President Truman has asked the country to save through his “halt-ali-waste” campaign.
But the rat is an even greater danger as a destroyer of human life. Centuries before mankind ever dreamed of bacterial warfare, the rat was waging his own germ war on a mammoth scale, spreading several of our deadliest diseases such as bubonic plague and typhus. Biologists say, and
they can quote figures to prove it, that the rat has caused more human deaths than all the wars in history. And despite the advances of modern medicine he’s still a serious potential threat—for rats have been getting a lot smarter over the years, too.
Mammalogists say it’s a tossup whether the rat, the fox or the wolf is the smartest animal that walks on four legs, but on one point they are in complete agreement—every generation that the rat lives with man makes the rat race a bit smarter. In laboratory tests for determining animal intelligence, some rats show a capacity for learning faster than human beings. And the rat is such a fierce and fearless fighter that those placed in snake pens as food for rattlesnakes sometimes overcome and eat the rattler instead of being eaten themselves. Little wonder some scientists say that, if they continue becoming smarter, the rats will some day drive men from the face of the earth and take full possession for themselves.
No one knows for certain when the rat invasion of Canada began. Ships from the Old World brought the first rat immigrants to our seaports probably more than a century ago. In time they found their way into freight cars of meat, grain or other foods and spread inland.
Up the Lakes
THE SPREAD of the rats eastward from the Pacific seaboard was much slower than the westward movement from the Atlantic, but these western rats have finally been able to bypass the British Columbia interior and establish flourishing rat settlements on the eastern slopes of the Rockies in Alberta’towns like Lethbridge and Calgary. The faster trekking rats from Atlantic seaports were fanning out over Ontario in the 90’s, boarding lake ships for Port Arthur and Fort William before the turn of the century and crossing from Manitoba into Saskatchewan by 1912. Marching relentlessly on at about 10 miles a year, by 1946 they had reached Lancer, a town in southwestern Saskatchewan about 50 miles from the Alberta boundary and were ready to leap that last gap separating them from their western brothers.
Their opportunity came in July last year . . . A grain train loads in Saskatchewan for the west coast and, unknown to the freight men, a family of rats boards one of the boxcars. The train rumbles westward. It is opened in Calgary for inspection and the rats scurry to the open doorway, drop to the ground and are gone . . .
The East and West had met. Their encirclement of the world was complete.
Today there are rats in Alaska, in Iceland and Greenland, on most of the islands of the Pacific and on a few islands of the Antarctic Sea almost to Antarctica—and, of course, on every one of the five world continents.
What manner of beast is this world conqueror who has defied man and defiled man’s dwellings since the dawn of history, until today, even with our modern knowledge of poisons and trappings, he is more plentiful and wreaking more damage than ever before?
Rata belong to the rodent group of mammals, not-so-distant kin to the mouse, squirrel, rabbit, beaver, .muskrat, porcupine, woodchuck, prairie dog and guinea pig. Mrs. Rat is a solicitous mother. In a burrow under your basement or barn, or less frequently in a partition above ground, she fashions a snug round nest where
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for two weeks she suckles and lovingly cares for her brood of around 10 youngsters. The nest is usually composed of pu per, cotton, wool or other fabric, (rats are far too domesticated to be satisfied with straw) which Ma Rat has stolen somewhere and which she painstakingly tears into shreds tor her home-building. One rat’s nest in New York was found to be composed entirely of dollar bills—17 of them. After two weeks of mothering, the youngsters are ready to fend for themselves—just as well too, for Mrs. Rat will soon have another family on the way for whom she must hustle about and build a new nest.
Rat of Many Aliases
But Mr. Rat—well, he’s a rat. All he does is eat and gad after the girls. He takes no interest in the families of his numerous wives, unless he gets hungry—then he might eat them.
There are only two species of house rat—rodents like the pack rat and wood rat are not true rats and deserve little of the infamy associated with their name.
The commonest house rat in Canada and in most parts of the world is the brown rat, alias Norway rat, wharf rat and sewer rat. Call him Rattus norvegi-
cus if you want to he bookish, but whatever the name he’s still a rat. The other one is the black rat, alias roof rat, alias ship rat, alias (let’s be bookish again) Rattus rattus rattus.
The brown rat weighs about a pound, is 16 to 18 inches long from snout to tip of tail, greyish-brown in color and his tail, when bent forward, does not reach the end of his nose. The black rat is smaller—about two thirds the size of the brown is dusky black instead of brownish, but he flouts a tail that can extend considerably beyond the tip of his nose. All house rats have naked scaly tails.
Both rat species originated in the Orient where man first became a civilized being. Since prehistoric times they have dogged man’s footsteps, following him when he was a wandering tent-dwelling hunter and entering his home to live from the scraps of his table as soon as he learned to erect more permanent dwellings. The black rat got ambitions of world conquest first. He moved into Europe around 1000 A.D. By the early 1700’s he had occupied every country of Europe— but then the brown rat got the bug for conquest. The brown rat is bigger and tougher and since he liâtes his black cousin he drove Blackie out and took all but complete possession for himself.
The black rat came to America first, but the bullying brown rat made his appearance around the 1770’s and soon liad the black on the run again.
Today 90% of Canadian and U. S. rats are of the brown species and Canada has black rats only in Halifax and Vancouver. Yet though a persecuted minority the black rat is a more dangerous disease threat to man because he’s a chummy chap who prefers to live above ground in houses. The brown, though definitely a house dweller too, sticks closer to the ground, living in cellars or in burrows under buildings which have no basements, and he comes up into houses only when he’s looking for something to eat. For this reason, the black, when he is present, comes into closer contact with man and he is more likely to disseminate the rat-borne diseases such as bubonic plague and typhus.
If any one calls you a rat, brother, you’re being insulted. Scientists who study the interrelationship of animals usually have some kind word for every creature, because, no matter how damaging, practically every animal contributes something worthwhile to nature’s pattern of life. But there’s nothing good to be said about the rat. He’s one animal we could get along very well without and the damage he does is staggering.
In warehouses, on farms, in stores and dwellings they eat thousands of tons of grain and other food each year, and surveys have shown that they
destroy and defile three times as much as they actually eat—by chewing up bushels of apples, for instance, just to get the seeds. They kill vast numbers of young poultry. They gnaw holes in bags, boxes, doors and foundations to reach the food they want. They cause fires by gnawing the insulation off electric wires.
A Toronto man brought a section of lead water pipe to biologists at the Royal Ontario Museum of Zoology recently; it had a hole in it large enough to stick three fingers through. “I got up this morning and the cellar was flooded,” he said. “Then I found this. Look—teeth marks, aren’t they?” Teeth marks they were—rat teeth.
Their appetite is as widespread as their world travels. They eat books to get the glue in the bindings, they eat paint, bone and leather. And their fondness for eating soap is the only clean characteristic about them. Sometimes, when they are hungry enough, they try to make a meal of human flesh—alive. Many a sleeping child’s face has been mutilated by rats before the child has awakened and occasionally the bites have introduced ratbite fever or other disease which has caused death.
The last Canadian death attributed to this cause was in February, 1943. The victim was a two-day-old Nova Scotia infant who, according to evidence revealed at a coroner’s inquest, was bitten by a rat in the nursery of a
hospital ei New ',1a gow aed cli'd shortly af arwsrd. Levs Ae.g'ist penicillin successfully checked the spread of infection when a three-weeks-old gin in Long Branch Ont., was bitten on the nose and two fingers by a rat.
Several years age rats got into a fur warehouse in T ato and chewed out ihe noses of a number of silver fox pelts; flu* rats are believed to have been at worn oniy uiree nights, Dut the loss was over $3,000. On a New Hampshire poultry farm recently rats killed almost 1,000 laying hens in a little more than a week. The farmer shut six cats in his poultry buildings but next morning only two were left alive.
With Him Goes Death
Appalling though such losses are, they are less important than the toll of human lives for which the rat is responsible. He’s the filthiest, deadliest disease carrier known to science.
Bubonic plague, the notorious “Black Death” of history, one of the most dreaded of human diseases, is spread only by rats. A disease characterized by high fever, convulsions, delirium and black painful swellings of the glands in the groin and armpits, the plague strikes quickly, sometimes causing death within 24 hours. Medical men say that if the world could be rid of rats, the plague bacteria would virtually disappear. Humans never get the disease directly from the rat but from the bite of a flea which has lived on a plague-infected rat.
Fortunately, none of the millions of house rats in Canada and the U. S. are infected with the plague at the present time, but in seaports where rats are continually arriving on ships from foreign lands the threat of a bubonic outbreak is always present. Hundreds of thousands of dollars are spent annually in Canadian and U. S. seaports to guard against this threat. In large ports, rat inspectors go over every ship before it is permitted to dock. If signs indicate that rats are present, the ship’s hold is sealed up and fumigated. Dr. Robert Olesen, medical director of the New York quarantine section of the U. S. Public Health Service, says this practice has killed a number of stowaways and now tear-gas bombs are exploded in the hold first, to rout the stowaways out. If a ship has come from a foreign port where a plague epidemic exists, a few of the dead rats are combed to obtain a sample of the fleas they carry. The fleas are mashed up in a laboratory, put into a solution and injected into guinea pigs. If the fleas carry the infection, the guinea pigs sicken and die within two to four days. Not until the scientists are sure that the guinea pigs are going to survive is the suspected ship allowed to dock.
Pest-control authorities say that if a single plague-infected rat got ashore and roamed for a few hours among the uninfected rats of Halifax, Vancouver, or New York, it might start an epidemic that could sweep across the continent before being controlled. Bubonic plague is a rare disease in the U. S. and Canada solely because of the thoroughness with which our seaport antirat guardsmen do their job.
But Canadian and U. S. medical men must maintain a constant guard against bubonic plague from yet another source. In 1934 biologists of the U. S. Public Health Service discovered that plague infection was present in thousands of burrowing rodents—ground squirrels, prairie dogs and chipmunks—in western U. S. The original source was traced to San Francisco where, during the plague epidemic of 1900, many rats fled inio the suburbs and transferred their contaminated fleas to wild squirrels.
I . 943 i v 'as d íacover >d t at the
dise to had spreid among prarie roderas almost as ar eastward as the Mississippi and northward into f Alberta. Departments of public health in Alberthave had field mw ut every summer since 1938 tracing the i-xionl of the infection and '•Gskatchewun has Ix'en on guard since ;12. It is re}*tried
to he ¡eesen! in !\v -reas of Alberto_____
around Stanmore and Hanna— ' at has not yet been discovered in .'Saskatchewan, although many wild rodents in North Dakota are infected.
Medical men say the plague has failed to break out into epidemic proportions in the West because the rodents which carry it inhabit thinly settled areas and rarely come in contact with house rats or humans. Even so, every year a few U. S. hunters are bitten by infected rodent fleas and come down with the plague. And usually the disease is fatal. Canada is believed to have had only one death from this source in recent years. An Alberta mink rancher, seeing a number of dead gophers lying around, gathered them up for mink food and cut his thumb while skinning one of them. He died a short time afterward from what was thought at first to be blood poisoning. Authorities now believe that the man died from bubonic plague.
In June, 1943, Alberta members of the House of Commons asked for federal aid in poisoning out the infected gophers of Stanmore and Hanna areas, hut Dr. J. J. Heagerty, director of Public Health Services, said the danger to humans was negligible and no federal aid was granted. Dr. Heagerty pointed out that the disease had been present on the continent, since 1900 and no epidemic had resulted.
Some U. S. officials claim, however, that western U. S. and Canada are sitting on a bacterial powder keg that could explode any day. Dr. C. R. Eskey, U. S. Public Health Service bubonic-plague expert, who has studied the disease in numerous foreign countries as well as in western U. S., told the American Association for the Advancement of Science that the western situation was “a great potential danger to the inhabitants of this country.” Should the rodents transmit the disease back to our town and city rats again, he said, medical authorities would be up against one of the stiffest disease battles of American history. Despite some aid from new drugs, bubonic plague is still one of the worst potential killers among all diseases.
Other rat-borne diseases are a form
of typ’ '*> fever known as Brill’s di» ase (also so.-ead by the rat flea >, spirochetal jaundice (contrai ted from food, water or »vil contaminated by the urine of tue rat trichinosis (a worm disease spread trom rats to pigs and then to humans through insufficiently cooked jx>rk ), oui rat bite fever and rabies (/rom ratio tes).
The ra* 5"® ••-'rempli.-:., d Ius glotiegirdling , ¡ mvgy by means of two formidable racial characteristics. He multiplies faster than interest at 10% and—he’s smart.
First, let’s look at that matter of multiplication. In the temperate climate zone, rats average six litters of young a year and about 10 youngsters to a litter. Every one of those rats when it becomes three months old commences producing young of its own. At this rate in three years—the rat’s average life span—one pair of rats could become 359,709,480 rats—a pile approximately the size of Toronto’s 34-story Bank of Commerce building. Of course, natural factors like disease, food supply and enemies hold all animal populations at a down-to-earth level.
The rat has been dependent on man for so many centuries that he has developed characteristics that are amazingly human. Like man, his appetite is practically omnivorous, he
breeds at all seasons, makes himself at home in almost any climate, has his racial prejudices (brown versus black) and . . . ahem . . . the males are more muscular, the females stoutish; Animal psychiatrists claim that laboratory rats, when thwarted in some desire or when faced with a difficult decision, chew fingernails like humans.
But their long association with humans has had the greatest effect on their intelligence. Dogs, cats and horses are potentially clever, but usually they have to be trained; the rat is naturally resourceful and he is capable of thinking things out for himself without human tutorship.
Experimenters at the University of North Carolina have proved that rats are capable of working together intelligently. Several rats were placed in a feeding cage with an electrified wire bottom through which they received mildly uncomfortable shocks. The only way in which the shocks could be turned off was for a rat to stand on a platform at the opposite end from the food. The rats soon learned the connection between the platform and the electric shocks. And they learned to take turns at shock-stopping duty, one rat standing on the platform while
the others ate. If the rat on pitot) ri duty thought the others ^ere • ¡¡tin« mow* than their share, he’d planone foot on tiie platform and switch the current, on end off until another rat came back to relieve him.
Dr. Frank A. Beach, U. S. expert c nn;u;:i’ intelligence, has desertk ;H rímente confluet«! in a f*o conep in whirl; 27 nits competed with 38 students m a learning aptitude teat. Two mazes were used—a small one for the rats and another, identical except in size, for the students. Each maze consisted of a labyrinth corridors and at 25 different points there was a cross corridor, one tun. leading into a blind alley, the other along the correct route. The students and rats were sent through again and again until every one had made three successive perfect runs through the maze and a record of the wrong turns made by each group was kept. 'Then the professors in charge added up. The students committed nearly twice as many errors as the rats before all could make their three successive perfect runs. Embarrassing, eh?
“Does this mean that men are no more intelligent than rats?” Dr. Beach asks. “Of course not,” he adds reassuringly. “Maze-running involves the trial-and-error method of learning gives no scope for man’s sup reasoning ability. But it does p that for memorizing or rote lear* the rat brain is keener than the hu. brain.”
Tough to Kill
When nature tossed that degree intelligence into an animal with t reproductive prowess of the rat, sh gave man a tough pest to c«intn,;|, Traps and ordinary types of poison , like red squill and arsenic, can alwajr he relied upon to knock off a few nit#, hut there are always a few more smart enough to recognize a trap or smell ou a poison bait before they get within aí feet of it. And any control measur that allows a few rats to escape \ practically useless, for those few ca become hundreds in a matter of week# Recently a new type of poison calle ANTU, containing phenyl thiouw has been developed which leaves i;-. telltale taste or smell, and professio f exterminators are now having bet * luck with this new brand.
But, in general, trapping and pois©*; ing is not an efficient method of \ vagir, war on the rat. Experts say the bes method of controlling them is to ratproof all buildings where they are likely to find food and to dispose of all garbage before it can become a rat banquet table. This creates a food-andhousing shortage for the rats; they resort to cannibalism and when they can no longer eat. each other they*11 starve to death.
Back in the 14th century the rats almost succeeded in wiping out the human race. By spreading bubonic plague across Europe they caused the deaths of 25 million people in a period of just a few years—three quarters of the population of Europe, one quarter of the population of the world of that day. But, of course, you say, mankind is a lot smarter and more capable of defending itself against such catastrophes today. But, trouble is, the rats are smarter too. We’ve been fighting rats tooth and nail ever since those years of the Black Death, but the rats have kept right on spreading until today they threaten us in every corner of the globe. Now that they can’t overflow into new and rat-free areas, what will the rats do next? No one knows, but, being rats, whatever the do will bode ill—and plenty of it ft;r mankind. it