Monday, December 5 , 2022

Mouse, man’s worst friend


One day you decide to clean the pantry of home and – surprise! – Discovers that the place is infested with mice. The food bags are punctured and empty, nor have the household appliance packaging been saved. The presence of the animals is disgusting, but there is no reason for despair, you think. After all, there is an arsenal of poisoned traps and lures on the market. Once you have a perfect trap, you go to sleep quietly, sure that the intruders are on time. Sweet illusion. The next day, the traps are untouched. The mice didn’t take a bite. Instead, they devoured a little more of the remaining food, as if guessing their intentions. Are these rodents really that smart?

Well, if rats were that easy to defeat, they wouldn’t be one of humanity’s oldest – and most hated – enemies. According to American zoologist Anthony Barnett, we have been trying to get rid of them for 10,000 years. “We’ve been living with rodents at least since agriculture began,” says Barnett, professor emeritus at the National University of Australia and author of The Story of Rats. After so much time together, it is no wonder that the toothy have learned our crazes and flaws and developed tricks to live with us without taking too much risk.

But living with humanity has not only changed the lives of mice. According to Barnett, these animals, in the opposite hand, altered the history of humanity as well. Especially in science, but not only. Cats were only admitted to houses after people realized their usefulness in rodent hunting. Even in the Bible, rats deserved a quote. In some passages, written 3,000 years ago, they are classified as “unclean.” God-fearing men should keep their distance from them.

This historic raid had two crucial moments. The first of these was the founding of the first cities 10,000 years ago, which have since provided an inexhaustible source of food and shelter for rodents. “We provide them with a lot of food and good survival conditions,” says Neide Ortêncio Garcia, from the São Paulo Zoonosis Control Center. So much so that of the thousands of forest rodent types that can survive on plants and insects, the three most numerous species in the world are those that live in sewers, dumps and city streets. They are the rat (Rattus norvegicus), the roof rat (Rattus rattus) and the mouse (Mus musculus).

The great navigations of the fourteenth century sealed the alliance of moustaches with us for good. Aboard the caravels and other vessels, these three species spread from their place of origin – Eurasia – to the rest of the world. Few times, by the way, men and rodents have been so close. They infested the ships, and ate the same food as the sailors. Killing them helped the crew alleviate boredom, but it also provided a good meal. One of the sailors of Fernão de Magalhães (1480-1521) – commander of the first voyage around the world – reported that he regretted eating cookies that stink of rat urine and could not get any of these animals to eat. “They were probably a good source of vitamin C and helped alleviate diseases like scurvy,” says Barnett.

Disgusting is relative: until today we enjoy rats as food. Irulas, an ethnic group from southern India, catch thousands of mice a year, cook them and place them as ingredients for a rich (but not necessarily delicious) meal. For those with a strong stomach and no worries about disease, Larousse Gastronomique, one of the world’s leading cookbooks, features a recipe in which rats and rats should be cleaned, peeled, seasoned with oil and onions, and grilled over high heat.
Hard to kill

For traditional-minded people, though, having rats in the pantry doesn’t mean having one more item on the menu of the month, but just a difficult problem to solve. Among the many tricks that rats and roof rats have developed to prevent our attacks is a special ability to avoid traps and devour only healthy food. This is not a sixth sense or diabolical cleverness: they simply have an aversion to new objects placed in a known environment, feature scientists call neophobia. As mousetraps and poison are new, they end up untouched. Already the food that was there…

It takes cunning to capture a mouse. “There are a lot of strategies to fool them,” says Neide. One is to put harmless little foods for days until rats get used to eating them, and then add poison. Another trick is to use chemicals that only take effect more than five days after ingestion, which prevents animals from relating the death of one of their mates to ingested food. Mousetraps only work with less suspicious species, such as the mouse. “The most effective thing is to remove the available food and, with it, the survival conditions of rodents,” says Neide.

Why exterminate the mice? Because they transmit the disease to humans. There are at least 55 diseases, according to Norman Gratz, a retired biologist at the World Health Organization (WHO), who listed diseases transmitted directly or indirectly by the tail. But he himself acknowledges that the number is certainly higher. None had a greater impact than the Black Death, which began in the 14th century in Asia and invaded Europe. One hypothesis states that during a battle, Turkish warriors, unable to break through the walls of a city in present-day Ukraine, hurled contaminated corpses into the walls. The plague, caused by rat-flea-borne bacilli, spread rapidly and killed about 25 million Europeans – a third of the continent’s population at that time.

But the list of serious rodent-borne diseases does not end there. Leptospirosis, for example, an infection caused by a bacterium that causes fever, pain and sometimes bleeding and death, is transmitted through the urine of mice. The disease infects hundreds of people each year and is one of the biggest flood risks. And then there are the diseases caused by hantaviruses, microbes that live in rodent secretions and are transmitted through the air. Although detected a few decades ago, hantavirus diseases have already spread worldwide and had a high mortality rate. “Mice are a global, underground network of disease transmitters,” says Bartlett.

Specialists and Bored

Thanks to their diversity, the three species of human-adapted rats occupy different habitats and eventually cover virtually every possibility of human coexistence: mice, for example, prefer enclosed spaces (such as a closet). Roof rats are usually found in the environment that gives them the name. Rats usually dig holes in the ground and have an amazing ability to walk in these tunnels.

In their habitat, they are effective as professional athletes in their speciality. Experiments with labyrinth mice, which have been in existence for over a hundred years since 1900, have shown that these animals are not only able to learn the paths quickly, but can invent shortcuts and return to the starting point without difficulty. One biologist likened this skill to that of a pianist who, after learning a piece, can play it back and forth with the same ease. In this area, the intelligence of rodents rivals that of humans. Scientists experimented with college students and mice needing to find mazes of identical design coming out. The humans lost their washing: rodents not only managed to get it right at first, but they also recorded the route faster. However, student performance improved over time, and after much training, they managed to bring the trophy to our species. Ufa!

It is unclear what the origin of this incredible spatial notion is, but some factors help the mice. One is whiskers, which act as sensory organs and allow them to find their way even in the dark. Also important is the natural taste for exploring new environments. Even hungry, a rat that is placed in an unfamiliar place will explore the entire environment before leaving for the meal. He can learn the ways, find new partners, water or shelter, and, amazingly, relieve boredom. Rats tend to prefer new situations. And they often get sick of repetitive activities. If we train a guinea pig to turn the cage light on and off, she will at first turn the switch just for the fun of the change. Only when you are tired of the joke will you leave the room with the brightness you find appropriate.

A taste for change can be very helpful for rodent learning, as some experiences of Canadian psychologist Donald Hebb, one of the pioneers of psychobiology, have shown. He took some roof rats to his house, where they could play with his two daughters, one five and one seven. After a day of fun, these lucky ones fared much better in the lab tests than their colleagues who got stuck in cage boredom.

The intelligence and learning of rats also extend to the main factor of your life: food. If you have access to various types of food, a rodent will eat a little of everything and maintain a balanced diet in calories and nutrients. Some research indicates that humans would also have this innate ability, but today’s access to very tasty and unhealthy foods has messed up our eating habits. Despite having a healthy diet on instinct, rats also learn from their ancestors the places that offer good meals and identify from the smell of other rodents that foods can be attacked without a problem.
Eat (almost) no frills.

Despite all the knowledge about animals, scientists still face peculiarities. In one experiment, even before the study began, a group of researchers faced a dilemma: rats did not like the food they were given, a well-known brand of morning cereal. The test only went ahead when someone forgot about a piece of the cereal wrapper. The mice loved the snack, and the experiment was finally done.

Food is critical to understanding rat society. It is the food, or rather its quantity, that determines the size of a rat population. “When there is a lot of food, females breed more,” says biologist Luiz Eloy Pereira of the Adolfo Lutz Institute in São Paulo. In abundant situations, rats have a gestation of only 22 days, can have up to 13 puppies at one time and become pregnant again 21 hours after giving birth. That is: in a year; a female can give birth to more than 200 fluffies.

But overpopulation gives rise to conflict, and the biological programming of rats also predicts this situation. If the environment is already crowded and low on food, the number of puppies will be smaller and, in some cases, the female may even devour some of those born. “Rats struggle to dominate space as well as food sources. They are territorial animals that do not accept invasions,” says Luiz Eloy. Fighting between males involves kicks, scratches, cuts and bites, but never leads to death, or at least not. However, Finally, keep your house clean if you need take support from apartment cleaning Chicago services.

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