Where Do Rats Come From?

Bill Swank
First Published: | Updated: February 27, 2024

Rats are thought to have originated in Asia and spread globally through human travel and trade. This post will trace the historical journey of rats, focusing on how they have adapted and thrived in diverse environments alongside human expansion. Understanding the origins and adaptability of rats is key to understanding their persistence in urban, rural, and wild landscapes.

  • Rats originated in Southeast Asia around 5 million years ago, with their evolutionary history tracing back to ancient migrations and diversification in various species, particularly the brown rat (Rattus norvegicus) from northern China and the black rat (Rattus rattus) from India.
  • The global spread of rats has been closely tied to human activities, as they traveled as stowaways on ships, particularly during the Age of Exploration, leading to their presence on almost all continents.
  • There are over 60 known species of rats in the genus Rattus, with the diversity of species resulting from their evolutionary adaptation to different environments and the spread facilitated by their close association with humans.
  • Rats have played a significant role in human history and culture, from being seen as pests that infest homes and spread diseases like the Black Death to being symbols of prosperity in various cultures.
  • Despite modern pest control efforts, rats have shown remarkable adaptability to urban, suburban, and rural environments, thriving in areas with abundant food and shelter provided by human activity, making them one of the most successful mammalian genera on the planet.

Geographical and Evolutionary Roots of Rats

Rats, the small yet remarkably adaptable creatures that often find themselves unwelcomed guests in our homes, have a deep-rooted history that intertwines with the evolution of the Earth itself. Understanding where rats come from involves a journey back millions of years to their geographical and evolutionary origins.

Rats likely hail from Southeast Asia, with fossil records pointing to their emergence around 5 million years ago. This region provided the perfect backdrop for their evolutionary development, offering diverse habitats and climates for rats to thrive and diversify.

Rat Origin and Evolution

The evolutionary tale of rats is a saga that begins in the ancient landscapes of Asia and North America, where the earliest ancestors of modern rats appear in fossil records dating back about 54 million years. This period, straddling the end of the Paleocene and the dawn of the Eocene, marks the era when these proto-rats first scurried through the underbrush of primeval forests.

Evolutionary Ancestry

The lineage of rats is believed to have branched off from anagalids, a now-extinct family of small, rodent-like mammals. These creatures are not just the forebears of rats but also the direct ancestors of Lagomorpha, the order that includes rabbits and hares. This common ancestry highlights the shared traits and evolutionary paths between these seemingly disparate groups.

Emergence of the Muridae Family

It was during the late Eocene, approximately 34 million years ago, that the Muridae family, which encompasses the genera Rattus and Mus (the latter includes common house mice), first made its appearance in the fossil record. Over time, through a series of evolutionary refinements during the Miocene era, about 25 million years ago, these early murids evolved into the diverse and widespread species we recognize today.

Rise of the Rattus Genus

The Rattus genus, which is native to regions such as Southeast Asia, Mediterranean countries, and the Middle East, emerged from within the murids around 5 million years ago. This significant evolutionary event set the stage for the proliferation of a multitude of new species, each adapting to their unique environments and challenges.

Divergence of Brown and Black Rats

Two of the most notable descendants of this genus are the brown rat (Norway rat) and the black rat (Roof rat), which diverged from their common ancestor approximately 2 million years ago. Since that split, both groups have undergone significant evolutionary changes, leading to the distinct species we are familiar with in the modern era.

Current Diversity

Today, the genus Rattus boasts 51 known species, each with its own ecological niche and set of adaptations. These species continue to demonstrate the remarkable evolutionary plasticity of rats, allowing them to inhabit a wide range of environments and often live in close quarters with humans.

Understanding the deep evolutionary roots of rats provides insight into their resilience and adaptability. It’s a history that spans tens of millions of years, showcasing the remarkable journey from small, inconspicuous mammals to the widespread and often notorious rodents of the present day.

Global Distribution of Rats

Where are rats native to? While Southeast Asia is regarded as the cradle of rat evolution, these rodents have since spread across the globe. Their adaptability and reproductive success have allowed them to colonize a vast range of environments.

  • Brown Rat (Rattus norvegicus): Originally from northern China or Mongolia.
  • Black Rat (Rattus rattus): Likely originated in India.

These two species, in particular, have become the most globally widespread, due in large part to human activity.

Historical Journey and Spread of Rats Across Continents

The historical journey of rats is a tale of accidental yet consequential travel, as these creatures spread from their native lands to new continents and ecosystems, often with profound effects.

Rats’ Migration with Human Help

How did rats get to America? The answer lies in their uncanny ability to stow away on human modes of transportation. As humans ventured across seas, rats were right there with them, hidden in the cargo holds of ships.

Spread from Asia and Europe

  • Asian Rats: Spread to the Middle East around 3600 years ago, then Africa, and later on, other continents through European trade routes.
  • European Rats: The brown rat’s spread is more recent, reaching Europe in the 1500s and North America by the 18th century, likely through shipping vessels.

Their arrival in new lands often spelled trouble for native species and human economies, as rats are known to be both prolific breeders and voracious consumers.

Arrival in America

When did rats come to America? It is believed that the brown rat made its American debut around 1750, likely aboard European ships. Their arrival marked the beginning of a challenging relationship between humans and rats in the New World.

Diversity and Species of Rats in Relation to Their Origin

The diversity among rat species is a testament to their evolutionary success. With over 60 known species, rats have conquered environments from tropical rainforests to urban jungles. Their origin story is a patchwork of adaptation and survival, leading to a wide array of species, each with unique traits suited to their habitats.

The Varied Species of Rats

What species is a rat? Rats belong to the genus Rattus, within the family Muridae. This genus includes a variety of species, but the most prominent ones are the brown rat and the black rat.

How Many Species of Rats Are There?

There are over 60 species of rats, each with its own niche and adaptations. This diversity is a direct result of their evolutionary history and the spread facilitated by their close association with humans.

Scientific Classification

The scientific name for rats, Rattus, is just the starting point. For instance:

  • Brown Rat: Rattus norvegicus
  • Black Rat: Rattus rattus

These names reflect their scientific classification and hint at their geographical origins.

Evolution and Spread Leading to Diversity

The evolution and spread of rats have been influenced by natural selection and their ability to adapt to human-altered environments. As they moved across continents, they encountered new challenges and opportunities, leading to the vast array of species we see today.

Rats’ Impact on Human History and Culture

Rats have not just been passive travelers in human history; they have actively shaped it. Their presence has been recorded in ancient texts, and their influence can be seen in everything from the spread of diseases to cultural representations.

The Impact of Rats on Human History

The history of rats alongside humans is a narrative of opportunity and adaptability. Rats exist alongside us primarily because our settlements provide them with abundant resources. Throughout history, from the granaries of ancient civilizations to the waste bins of modern metropolises, rats have found human habitats to be fertile grounds for sustenance and shelter.

Early Associations with Human Settlements

The relationship between rats and humans dates back thousands of years. As humans began to farm and store surplus crops, these activities attracted rodents, including rats, which found a reliable food source in the stored grains. This was particularly evident in ancient civilizations along the Nile, Tigris, and Euphrates rivers, where granaries were a central feature.

Rats in Historical Records

Historical records, including writings from Ancient Rome and Medieval Europe, often mention rats as common pests. They were known to infest homes, food supplies, and even cause damage to infrastructure with their gnawing habits. The spread of rats was inadvertently assisted by the human expansion of trade routes, which allowed rats to reach nearly every corner of the globe.

The Black Death and Rats

One of the most significant events in rat-related history is their association with the Black Death. Although it is now believed that human fleas and lice were the primary vectors, rats were long thought to have played a central role in spreading the bubonic plague throughout Europe in the 14th century, which led to the death of an estimated one-third of the continent’s population.

Rats in the Age of Exploration

During the Age of Exploration, as European ships set sail to discover new lands, rats were frequent stowaways. This led to the introduction of rats to new ecosystems, where they often had devastating effects on local wildlife and crops, particularly on isolated island ecosystems.

Industrial Revolution and Urbanization

The Industrial Revolution and the growth of urban centers provided even more opportunities for rats. The increase in waste and the construction of sewer systems created ideal environments for rats to thrive in close proximity to humans. The warmth and shelter of buildings, combined with the easy availability of food, made urban areas particularly attractive to these rodents.

Modern Pest Control Challenges

Today, rats continue to be an issue in both urban and rural settings. Despite advances in pest control technologies, their rapid reproductive rate, elusive nature, and intelligence make them challenging pests to manage. They have become symbols of urban decay and are often used as indicators of environmental health and sanitation standards.

The history of rats is deeply intertwined with our own. Their presence in our cities and towns is a reminder of the delicate balance between human development and wildlife management. Rats have not only adapted to the environments we’ve created but have also become an integral part of our shared history, for better or for worse.

Rats and Culture

Rats have been portrayed as both villains and symbols of prosperity in various cultures. Their background in human society is complex and multifaceted, reflecting our mixed feelings towards these creatures.

Rats’ Adaptation to Modern Environments

Rats have shown remarkable resilience in the face of modern urban development. They have adapted to live in:

  • Urban Areas: Rats have mastered the art of urban survival, exploiting our waste and infrastructure.
  • Suburbs: These environments provide ample food and shelter, from compost bins to attics.
  • Rural Areas: Even here, rats find ways to thrive, often at the expense of local agriculture.

Their ability to survive and adapt to almost any environment has made them one of the most successful mammalian genera on the planet.

Rats’ Resilience and Adaptability

Rats’ resilience is evident in their continued presence despite human efforts to control them. They have become adept at avoiding predators, including humans, and can quickly learn to circumvent our attempts at eradication.

What Are the Different Types of Rats?

Rats are diverse creatures with over 60 species, categorized primarily into two main types: Rattus norvegicus, known as the brown rat or Norway rat, and Rattus rattus, the black rat or roof rat. The brown rat is larger, with a stockier body, and tends to inhabit lower parts of structures and burrows, while the black rat is smaller and more agile, often found in higher locations like roofs and trees. Both types of rats are highly adaptable and have spread across the world, often through human travel and trade. Other less common rat species include the Polynesian rat, the Himalayan field rat, and the African pouched rat, each with unique adaptations to their native environments.

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