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Rats: The Bad and the Good

I've spent half a century writing for radio and print (mostly print). I hope to still be tapping the keys as I take my last breath.

Good and bad things about rats

Good and bad things about rats

Are Rats Good or Bad?

Rats live among us, and mostly, we don’t like them. Originally from northern China, brown rats are now found everywhere on the planet except in Antarctica. If only we could recruit the legendary Pied Piper of Hamelin to draw the pesky rodents out of our cities. But, as with so many things, we have to be careful what we wish for.

Rat-Borne Disease

The Black Death killed about 60 percent of the population of Europe in the Middle Ages. Rats take the blame for the catastrophe, although it was fleas, for which the rodents were hosts, that did the heavy lifting. Rat fleas carry the bacteria that cause bubonic plague and then transmit the disease to humans they bite for a blood meal.

The overcrowded and filthy cities in which Europeans lived meant they were in close proximity to rats and their fleas. Those same unsanitary and congested conditions exist in many developing world communities, so bubonic plague is still a scourge in some areas.

Were rats responsible for the plague?

Were rats responsible for the plague?

Transmitted Diseases

Rats also carry leptospirosis, which “Without treatment . . . can lead to kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, respiratory distress, and even death” (Centers for Disease Control and Prevention).

Other rat-borne infections include:

  • Lassa fever is common in West Africa and kills about 5,000 people a year
  • Salmonella is a common diarrheal illness in humans and can be caused by contact with rat faeces
  • Rat Bite Fever is pretty much self-explanatory and you don’t want it. Typical symptoms are vomiting, fever, muscle pain, joint pain, and headache. In about 10 percent of people, it is fatal.

Everything You Didn’t Want to Know About Rats

Caroline Bragdon is the city of New York’s rat expert. She holds “rat academies” to educate people about the rodents. The New Yorker reported on one of her training sessions in 2018. She said that rats:

  • “Make lots of babies fast;
  • “Live well with people; and,
  • “They can cut anything softer than steel.”

And here is some other trivia about rats:

  • They eat their own droppings for additional nutrition.
  • They can tread water for up to three days.
  • They can recognize people they have seen before.
  • The collective noun for rats is a “pack” or a “mischief”
  • Rats can collapse their skeletons, making it possible for them to crawl through a hole about three-quarters of an inch in diameter.
  • When they bite, rats can exert pressure similar to that of a crocodile; about 7,000 pounds per square inch.
  • While rats are reviled in western societies, they are often respected and even worshipped in Asia.
  • Some rats have learned to dangle their tails in water to attract fish that mistake the appendage for a worm. If the fish bites, the rat jumps into the water and snags it;
  • In theory, a single pair of rats could produce 359 million descendants in three years; predators, infant mortality, and disease keep this astonishing number from being achieved;
  • Rats can live without water longer than camels;
  • Estimates vary, but it’s said the average human is never more than 10 feet away from a rat; some say the distance is as small as three feet. But in the Canadian province of Alberta, you are always a long way from rats.

Rat-Free Alberta

Rats first appeared in the Canadian province of Alberta in about 1950, migrating across the Prairies from the East. This is when the province put up a stop sign on its border with Saskatchewan.

Phil Merrill heads up the rat control programme. He told the BBC that when the rats first appeared “we checked all the farms along the border where they were and poisoned them out. And we just don’t allow any more rats to come in.”


Rats Like Warm Weather

Geography helped. Alberta is bordered by the Rockie Mountains to the West and South. These are too thinly populated and cold in winter to attract rats. To the north, Arctic temperatures persuade rats to stay in warmer places.

But, the war never ends. Pest control officers are ever-vigilant about invaders from the East. The population is mobilized by posters with pictures of the offending critter and slogans such as “Kill Rats At Sight.” Some rodents slip through the cordon but don’t get far before being hunted down and bumped off.

In some parts of the world, rats are on the menu.

In some parts of the world, rats are on the menu.

The Upside of Rats

It’s time for rats to get new spin doctors. Unwillingly perhaps, they provide numerous services to humans.

Rats are similar to humans physiologically, hormonally, and neurologically; this makes them ideal subjects for medical experiments. They can be infected with human diseases and then studied as to how they respond to various therapies. Obviously, this is not something that pleases animal rights activists or the rats themselves, for that matter.

A Belgian charity called Apopo makes use of the acute sense of smell common among rats. The group trains African pouch rats to sniff out landmines in areas that have been conflict zones. The rodents detect the explosives but are light enough that they don’t trigger a blast. Apopo also trains rats to detect difficult-to-diagnose tuberculosis.

Lab rats have been used in studies about the psychology of learning. They have even been trained by electricians to pull wires through wall cavities.

And they are sanitation workers. They clean up a lot of our food waste, although that does mean they leave behind mountains of rat poop.

Also, we have to remember that rats, like all other life forms, are part of the food web. If we knock them out of existence―something that is very unlikely―there will be negative impacts up and down the food chain of which they, and us, are a part.

And, here’s something else to be concerned about. Researchers at the University of British Columbia say that rats have an amazing ability to host pathogens. If the rats are exterminated, the pathogens will look for other hosts, which could turn out to be us.

Do these faces scare you?

Do these faces scare you?

Bonus Factoids

  • Jack Black was Queen Victoria’s official rat catcher. He domesticated one rodent and started the keeping of rats as pets in England. In the United States, there are thought to be half a million pet rats.
  • It is a great irony that many people who have a horror of rats are kept alive by taking the blood thinner Warfarin, which was first developed as a rat poison.
  • The famous “You dirty rat” of James Cagney fame (He never actually said those exact words, although he came close) does a grave disservice to the rodents because rats bathe up to six times a day.


  • “Detecting Landmines.”, undated.
  • “Rats: Dangerous Vermin or Useful Members of Society?” Deutsche Welle News, undated.
  • “Bubonic Plague Still Kills Thousands.” Tia Ghose, LiveScience, September 27, 2013
  • “Rats May Be Disgusting, but It’s People Who Have Made the World They Thrive In.” Steven Belmain, The Guardian, February 25, 2015.
  • “Rat Academy Is in Session.” Tyler Foggatt, New Yorker, August 13, 2018.
  • “20 Things You Didn’t Know About ... Rats.” Liza Lentini and David Mouzon, Discover Magazine, December 7, 2006.
  • “Why We Should Learn to Love Rats.” Jonathon Brown, The Independent, March 26, 2009.
  • “How these Cities Became Rat-Free Zones.” Philippa Fogarty, BBC, May 21, 2019.
  • “Rats Are Everywhere, but Rarely Studied. One Canadian Project That Is Filling the Gap Has Made Disturbing Discoveries.” Oliver Moore, Globe and Mail, April 30, 2019.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2019 Rupert Taylor