what do gerbils have to do with plague

The Relationship between Gerbils and Plague

You might find it an odd question, considering gerbils are adorable pets, and plague is a dreadful infectious disease. At first glance, gerbils and plague seem unrelated. However, they share a profound and intricate connection rooted in history and influencing the modern era. In this article, I’ll guide you through exploring the relationship between gerbils and plague from historical, scientific, and societal perspectives, revealing the mysteries and insights between them.

Gerbils and the Historical Link to the Black Death

Gerbils, small mammals belonging to the rodent order, are primarily found in dry and semi-arid regions of Asia, Africa, and Europe. Among various species, the Mongolian gerbil is the most common and a popular choice as a pet.

These petite, diverse-colored, lively creatures with strong adaptability and ease of care have gained the affection of many. However, what you might not know is that gerbils have a close connection, especially historically, with the plague, notably the Black Death.

The Black Death, a severe infectious disease caused by the Yersinia pestis bacterium, primarily spreads through fleas and rodents. Symptoms include fever, headaches, nausea, vomiting, swollen lymph nodes, and bleeding. If left untreated, the mortality rate can surpass 60%. The most infamous outbreak of the Black Death occurred in 14th-century medieval Europe, known as the “Black Death Pandemic,” resulting in approximately 25 million deaths, about one-third of the European population. This catastrophe profoundly impacted European society, economy, culture, and religion, marking the end of the Middle Ages and the beginning of the modern era.

So, what’s the connection between gerbils and the Black Death?

According to historical records and scientific research, the origin of the Black Death is believed to be in the Central Asian region of Asia, precisely where gerbils predominantly inhabit. There, gerbils serve as the primary host for the Yersinia pestis bacterium, meaning gerbils can carry the bacteria without showing noticeable symptoms.

Fleas on gerbil bodies act as the primary vectors for the plague. They can feed on gerbil blood containing Yersinia pestis bacteria and then jump onto other animals or humans, injecting the bacteria into their bloodstream, thus causing a plague infection.

In the 14th century, increased trade and communication between the Eurasian continent led to gerbils and other rodents being transported as commodities or pets from Asia to Europe and Africa through caravans, ships, and carts.

During this process, fleas from gerbils and other animals also spread, carrying Yersinia pestis bacteria to new areas and triggering local plague outbreaks. The Black Death Pandemic, estimated to have occurred from 1346 to 1353, witnessed the spread of the plague bacterium from Central Asia westward, covering most regions of Europe, Africa, and the Middle East, resulting in the death of millions.

In Europe, gerbils were not only kept as pets but also hunted for food and even used in medicinal practices. Gerbil meat was considered a delicacy, their skin utilized for clothing and decorations, and their tails applied in treating diseases and wounds.

These practices increased human contact with gerbils, elevating the risk of plague infection. Additionally, gerbils interacted closely with other rodent species in Europe, such as mice, squirrels, rabbits, forming a complex plague transmission network, making it challenging to control the spread of the plague in Europe.

The historical connection between gerbils and plague is an intriguing and astonishing topic. However, a comprehensive understanding of their relationship requires scientific evidence and explanations. Fortunately, with the advancement of scientific technology, many researchers have conducted in-depth studies on the gerbil-plague relationship, unveiling the mysteries from biological, genetic, and ecological perspectives.

Scientific Explanation of Gerbils as Plague Vectors

Gerbils possess a lower body temperature, approximately 37°C, enabling them to resist the pathogenicity of Yersinia pestis bacteria without displaying evident symptoms. Gerbil blood contains a specific protein called anticoagulant, which prevents the formation of blood clots inside blood vessels, avoiding blockage of blood circulation and tissue necrosis. Gerbil immune systems can effectively clear Yersinia pestis bacteria, keeping gerbil plague bacterial loads low while still enabling transmission to other animals or humans through fleas.

The natural habitat of gerbils is in arid and semi-arid regions, where climate variations, such as droughts or floods, can occur. These disasters lead to a reduction in gerbil food and water sources, increasing survival pressure on gerbils and affecting their immune systems and stress responses.

When gerbil immune systems are suppressed, Yersinia pestis bacteria have the opportunity to proliferate in gerbil bodies, making gerbils hosts for the plague bacterium. When gerbil stress responses intensify, they secrete a hormone called adrenaline, stimulating gerbil fleas to produce more plague bacteria, turning gerbil fleas into effective vectors for the plague.

Scientific research elucidates the mechanisms of gerbils transmitting the plague. Gerbils are social animals that dig complex burrow systems underground, serving as their homes. Gerbil burrows have numerous tunnels and exits, connecting to other gerbil burrows or nests of surface-dwelling animals.

These connections facilitate frequent contact between gerbils and other animals, creating an extensive plague transmission network. When gerbil fleas jump from one animal to another, there’s a possibility of carrying Yersinia pestis bacteria to new hosts, triggering plague infections. If there’s human contact among these animals, the plague can potentially spread from animals to humans, causing human plague outbreaks.

Historical Impact of Gerbils and Plague

The relationship between gerbils and plague not only has scientific foundations but also historical implications. Gerbils, as the primary hosts and vectors for the plague, played a crucial role in the plague pandemic that swept through medieval Europe. The Black Death profoundly influenced European society, economy, culture, and religion, altering the course of European history.

The Black Death had a tremendous impact on European society. Due to the extremely high mortality rate of the Black Death, the European population significantly decreased, leading to a shortage of labor and sparking social upheaval and class struggles. On one hand, the Black Death elevated the status of peasants and workers, enabling them to demand higher wages and better treatment, even instigating rebellions and strikes against the exploitation and oppression of nobility and landlords.

On the other hand, the Black Death caused a decline in the power of nobility and landlords, compelling them to relinquish some land and wealth to cope with the effects of population decline and social turmoil. These changes facilitated the transformation of European social structures, laying the foundation for the rise of capitalism and the development of democracy.

The Black Death had a profound impact on the economy of Europe. Due to the devastation caused by the plague, both agriculture and industry in Europe suffered severe blows, resulting in a decline in production and a rise in prices. Simultaneously, the Black Death affected European trade and transportation, reducing connections between Europe and Asia and Africa, thereby diminishing Europe’s economic vitality and openness. However, the Black Death also brought about some positive changes in the European economy. The decrease in population led to an increase in per capita land and wealth, subsequently raising the living standards and consumption capacity of individuals.

Furthermore, the threat of the Black Death spurred the development of technology and medicine in Europe, leading to numerous inventions and innovations that laid the groundwork for the Industrial and Scientific Revolutions.

The terror caused by the Black Death led to a shift in Europeans’ attitudes toward life and death, influencing various fields such as literature, art, and philosophy. On one hand, the fear and expression of sorrow regarding death intensified, resulting in works describing the Black Death, such as Dante’s “Divine Comedy,” Boccaccio’s “The Decameron,” and Giotto’s “The Life of St. Francis.” These works reflected the dark and pessimistic atmosphere in Europe.

On the other hand, the Black Death also intensified Europeans’ appreciation for life and the pursuit of enjoyment. Works portraying humanism and individualism emerged, including Petrarch’s “Canzoniere,” More’s “Utopia,” and da Vinci’s “The Last Supper.” These works showcased a brighter and more optimistic atmosphere in Europe. The Black Death also significantly influenced Europe’s religious landscape.

Due to the calamity of the Black Death, Europeans began to doubt and resist the faith and authority of the church, believing that the church could not protect them from the torment of the plague and, in some cases, even considering the church as the main culprit. Some people chose to leave the church, seeking alternative beliefs and redemption, such as mysticism, heresies, and Judaism. Others opted to remain within the church but demanded reform and renewal, leading to movements like the Franciscans, Dominicans, and Wycliffe. These changes laid the groundwork for subsequent religious reforms and wars.

Gerbils and Plague from a Modern Perspective
The relationship between contemporary gerbils and infectious diseases remains noteworthy. While the Black Death is no longer a nightmare in Europe, plague continues to exist as an infectious disease, with hundreds of cases reported annually, primarily concentrated in certain regions of Africa, Asia, and the Americas.

Gerbils remain the main hosts and vectors for the plague, particularly in Central Asia, where the population and distribution of gerbils are increasing, elevating the risk of plague occurrence and transmission. Gerbils not only transmit plague but also other infectious diseases, such as Salmonella, Leishmania, and rabies. These pathogens can be transmitted to other animals or humans through gerbil saliva, urine, feces, blood, or fleas, causing infections.

Controlling the population and distribution of gerbils is challenging due to their reproductive capabilities. Gerbils reproduce prolifically, with the ability to breed four to five times a year, producing four to ten offspring each time. Moreover, gerbils have a relatively long lifespan, living up to three to four years.

Gerbils exhibit strong adaptability, surviving in arid and semi-arid environments, consuming various plants and animals, and creating complex burrow systems underground. They coexist with other animals, and their defense mechanisms include biting, scratching, and excretion to fend off enemies or competitors. Eradicating gerbils through methods like trapping, poisoning, or rodenticides is difficult and may lead to other ecological problems.

Although gerbils are closely associated with infectious diseases, it doesn’t mean they cannot be kept as pets. In fact, gerbils make excellent pets, possessing traits such as small size, diverse fur colors, lively personalities, strong adaptability, and ease of care. By following a few key points, such as selecting healthy gerbils, providing suitable living environments, monitoring their health, and preventing disease transmission, gerbils can be safely kept as pets, allowing for interaction and enjoyment.

Choose healthy gerbils by carefully observing their appearance and behavior before purchase. Look for gerbils with shiny fur, bright eyes, clean noses, clear ears, well-aligned teeth, agile limbs, and vibrant spirits. Avoid gerbils with dull fur, cloudy eyes, runny noses, dirty ears, overgrown teeth, stiff limbs, or lethargy. Additionally, inquire about the gerbils’ source, age, breed, gender, and health information, choosing those from reputable pet stores or breeding facilities.

Provide an appropriate living environment for gerbils. Being social animals, gerbils need companionship to feel happy and secure. It’s preferable to keep two or more gerbils together, ideally of the same sex or already spayed/neutered to prevent excessive offspring. Gerbils are active creatures, requiring sufficient space and toys to meet their exercise and entertainment needs. Ensure a spacious, well-ventilated, clean, and safe cage, with the bottom covered in thick bedding for digging and nesting. Place enough food and water, along with toys like wooden sticks, blocks, cardboard tubes, chew stones, exercise wheels, and swings to enhance gerbils’ enjoyment and vitality. Keep the cage in a warm, quiet, and shaded location, away from cold, noise, and bright light. Also, keep gerbils away from other pets like cats, dogs, or birds to prevent startling or attacks.

Monitor gerbils’ health regularly. Despite being resilient animals, gerbils can still get sick or injured. Regularly check their bodies and behavior, promptly identifying and addressing health issues. If gerbils exhibit abnormal conditions, such as weight loss or gain, dull or shedding fur (indicating skin or parasitic issues), cloudy or tearing eyes (signs of eye infection or trauma), runny nose or sneezing (respiratory infection or allergy), dirty or inflamed ears (ear infection or mites), overgrown or broken teeth (dental problems), stiff or swollen limbs (arthritis or fractures), lethargy or loss of appetite (digestive infection or poisoning), or abnormal behavior or increased aggressiveness (neurological or endocrine issues), seek immediate veterinary attention to avoid delayed treatment or life-threatening situations.

Prevent infection and transmission of infectious diseases by gerbils. While gerbils can resist the pathogenicity of plague bacteria, they can still carry and transmit plague and other infectious diseases. Follow these guidelines to reduce the risk of gerbil infection and disease transmission:

Ensure gerbils come from reputable pet stores or breeding facilities, not from the wild or unknown sources, to avoid gerbils carrying unknown pathogens.
Before introducing gerbils to other gerbils or pets, conduct isolation and quarantine to prevent gerbil infection or transmission of other pathogens. Isolate gerbils in a separate cage, observing their behavior and health for at least two weeks. If no abnormalities are observed, gerbils can be introduced to other gerbils or pets.
Regularly deworm and vaccinate gerbils during their care routine to prevent infection or transmission of parasites or viruses. Typically, deworm gerbils every three months and administer vaccinations like rabies and canine distemper annually.

Maintain cleanliness and disinfection of gerbil cages and toys to prevent the spread of bacteria or fungi. Clean gerbil feces and urine daily, replace bedding weekly, and clean cages and toys monthly using warm water and non-toxic cleaners, followed by drying with a clean cloth before returning to the cage.
Limit gerbil contact with other animals or humans to reduce the risk of gerbil infection or transmission of fleas or other pathogens. Place gerbil cages in an area away from other pets like cats, dogs, or birds to avoid startling or attacking gerbils. Also, prevent gerbil contact with other rodents such as mice, squirrels, or rabbits to avoid gerbils carrying and transmitting plague or other pathogens. When interacting with gerbils, wash hands and use gloves to prevent gerbil infection or transmission of human pathogens. Also, avoid allowing gerbils to bite or scratch, reducing the risk of self-infection or transmission of gerbil pathogens.


The relationship between gerbils and plague is an intriguing and meaningful topic that spans history, science, and society, revealing the mysteries and insights of gerbils and plague. Gerbils, as the primary hosts and vectors for plague, played a crucial role in the widespread occurrence of the Black Death in medieval Europe, profoundly impacting European history. Gerbils continue to pose a potential threat to modern human and animal health, as they may still carry and transmit plague and other infectious diseases. Despite this, gerbils make excellent pets, boasting various advantages such as small size, diverse fur colors, lively personalities, strong adaptability, and ease of care. By paying attention to key aspects of care, such as selecting healthy gerbils, providing suitable living environments, monitoring their health, and preventing disease transmission, gerbils can be safely kept as pets, allowing for interaction and enjoyment.

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