The Evolution of the Rat

The Evolution of the Rat


A study by the University of California researchers in San Diego shows how human beings, rodents, and mice have the same number of genes. Nevertheless, their genetic structure is significantly different. Comparisons between the genomes provide a great insight into the evolution of every species. For example, the study has already shown that rodents have evolved more rapidly than humans and mice. 

Rats are adapted for adequate forage, and breeds often produce sufficient progeny for rapid repopulation. There is an increasing number in towns and cities across the globe, despite millions of dollars per year spent to eradicate rodents. The majority of rodents are also rapidly recovering when control campaigns end — a situation called the “boomerang effect.” 

Smelly pipes

The rat has a good sense of smell that they use in danger identification, territory marking, and mates selection. A rat has around 2070 odor receptors, about a third more than mice, and much more pheromone scents. They have even zeroed in on gene production to help them detoxify toxins in and around their liver. 

Rodents exist in smelly sewage pipes and dirty areas, as compared to mice, mostly living in wooded areas and fields. That model suits the pattern for the production of their genes. It may be possible to “knock off” genes to make rodents genetically modified so that their detox machinery is similar to ours, enhancing toxicology and drug safety testing. 

sewer grate

Similarities are just as significant between human and rat genomes as differences. The researchers found that almost all human genes associated with the disease are the same in rodents, validating the use of rodents for research. The development of the rat genome, comprising 90.0% of its genetic code, will speed up genetic root research in people.

 Ancestral core

Rattus norvegicus ‐ incorrectly identified as a Norwegian immigrant in 1769 and not from its own indigenous Asia — turns out to have a DNA base of 2, 75 billion pairs. That’s a little less than 2.9 billion in human and a little more than 2.6 billion mouse DNA. Genome sequencing from 20 institutions in six countries found that human beings, rodents, and mice have the same number of genes. 

The sequence data also verified that rodents and mice were split into separate lines 12 to 24 million years ago. Researchers conclude that about 50% of the chromosomal rearrangements between the rat and primate lines occurred during this period. However, this value was found to be much lower for the primate line, suggesting that evolutionary changes have occurred more rapidly in rodents than in primates. 

Even now, all three species have 280 big, virtually identical blocks of chromosomes, which indicate they are essential. These one billion bases or so, are what the DNA sequencers call ‘ancestral core.’ 

brown rat

Lethal control campaigns against rodents

Exploring rat biology in wild populations, especially in urban environments, is an enormous challenge. To understand whether rodents in the city developed a range of pathological traits, researchers study these populations to determine the effects of lethal control on rodents’ larynx and other aspects of their biology. What will happen in places where they are frequently targeted by deadly force? 

While the return of the rodents is almost inevitable, researchers find that the repopulation of the rats is radically different from the rodents before the lethal control takes place. Brazil, for example, succeeded in lowering the rat population by half through an aggressive eradication program in 2015. However, it also saw a 90% decline in their genetic diversity. The loss of many of its rare gene variants was reported. A broad range of gene knowledge is considered essential to the response and survival of species in changing environments. 

Moreover, the chance of inbreeding among the remaining rodents was also higher, since the survivors were closer to each other. The Brazilian phenomenon is a perfect example of what scientists refer to as a genetic bottleneck. It can be quite severe by any standard. 


This suggests that the changes in rat behavior may have occurred in response to the effects of lethal control. They argue that urban rodents consume high amounts of highly processed sugars and fats, as well as high levels of animal protein and carbohydrates. Hence, there is an increase in the transmission potential of pathogens. 

In vulnerable populations, the main concern is usually the survival of endangered species in the long run. Pests such as rats, mice, roaches, and bugs are routinely tested intentionally by lethal control to kill their populations. 

The problem is that rare cooperation exists between the pesticide management workers, who work with cities or property owners. Mostly short timelines, inadequate budgets, and scientists who want to monitor the long term prospects of urban pest species creates conflicts. Long-term results are closely linked to the idea of ‘survival of the fittest’ in city rodents that survive the lethal control. 

Rodents supercharged genes enhance survival

Many, possibly most, groups are taken out by a successful rat control campaign. Survivors may have other characteristics that make them “strong” — capable of avoiding rodent’s exposure, snap traps, and other fatalities. Such survivors then make more baby rodents that have the same useful characteristics. 

If the control program makes it possible for the more suitable rodents to survive, the survivors will then use the high-resource minefield area in modern cities to breed and repopulate. Researchers have established specific genes that make popular rodenticides the least effective.

In particular natural populations of rodents routinely exposed to these toxins, specifically beneficial gene variants, have been identified. On the other hand, biologists are aware of severe consequences, similar to the risks associated with inbreeding in humans, for populations without genetic variation. 

Experts believe that during the lethal rat control program, rodents will lose much of their genetic diversity quickly. This variability is the key to species adapting through natural selection to changing environments — and urban environments can soon shift. 

A progressive decline in survival, reproduction, and other features related to evolutionary fitness may be a longer-term consequence for rodents subject to repeated control programs. Gradually weaker, sicklier rodents are the best way to handle rat infestation. 

Get rid Of Mice and Rodents

Rodents are evolving so fast. They develop super pathological features that make it difficult to eradicate them. Apart from genetic and biological control methods, A24 rat and mouse traps remain one of the most practical ways. Trapping is a good option if you don’t want to use rodenticides. Besides, the impact of such techniques is minimal. 

Before the rats migrate to another location, you want to have a complete rodent elimination. An efficient rat control program involves baiting and trapping for greater success. Nonetheless, when the population of rodents become big, start with high-quality rodent bait to kill the population rapidly and prevent growth. 

Consider the incorporation of a pest control system with exclusion methods, cleaning, and removal of hiding areas. You should also carry out regular rodent inspections. Comprehensive rodent control must be focused on long-term and sustainability targets to reduce tolerable numbers of populations. 


Through the years, rodents have been responsible for many horrible plagues and diseases. In the past, they have caused many pathogens to spread. Today, the exposure to most rodent diseases is not as critical due to improved sanitation, and successful control programs. 

Naturally, the most successful rat infestation control should be taken to minimize the amount of waste. Practical measures ensure you do not erode their viability or transform evolutionary gear into accidental superspecies. If you need more help, check our website for effective rat traps and rat baiting resources. 


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