Normally seen as companion animals or as terrible pests , rodents are one of the groups with the largest number of species among mammals . There are many myths about them, to the point that we know little about this interesting group of animals. We will talk about them below.


What are rodents?

In the animal kingdom, rodents are a group of mammals that involve mice, hamsters, and other associated creatures. They are usually ranked as the most numerous mammals on the planet. They are scattered over a large part of the planet , with the exception of the arctic areas . Typically, popular culture views them as companion animals, although few species have reached that point.

  • Rodent characteristics
  • Source
  • Evolution
  • Types of rodents
  • Species
  • Habitat
  • Feeding
  • Reproduction
  • Rodents as pets
  • What diseases do they cause?
  • Pests
  • Rodent control
  • Importance
  • Examples

Rodent characteristics

Among some of the most outstanding characteristics that we can name about rodents , are:

  • It is the group of mammals with the largest number of species . Such is the case that, in fact, these animals are scattered throughout almost the entire globe . The only sector that they do not inhabit is, of course, Antarctica and very similar areas.
  • So generally , they are treated small animals . This implies that the greatest size that some of these creatures can reach is one meter long.
  • As its name indicates (and we will see this in its etymology), rodents usually have very particular teeth. Their incisors are very hard and sharp , and these serve to ” gnaw “ many materials of different hardness (metals, inclusive).
  • Many specialists believe that the survival success of these animals is due to their ability to adapt . They are very fertile , having large litters of young. Apart from this, they have the ability to adapt to almost every environment on the planet.
  • They are usually considered, in some countries, as pests and real threats to public health .


Etymologically, the origin of the term rodent can be found in Latin. You could say, basically, that this is a conjugation of terms. On the one hand, we have ” rodere “ , which is a word that refers us to ” gnaw “ or other similar meanings. On the other hand, we have ” dor “ , which is a suffix that speaks of ” agent “ . We could say that etymologically, ” rodent “ is ” an agenda that gnaws . 


It could be said that the first rodents we found about 66 million years ago. This is known since the fossils found present the same characteristic of incisor teeth very similar to contemporary rodents . It is often said that these evolved quite a bit in America , Europe and, above all, in Asia . It is in this last continent where these species found a place to reproduce due to the extinction of other animals in the Cretaceous . It can be said that the first rodents were larger than today. It was in the Eocene when they adopted the characteristics for which we know them today.

Types of rodents

Today, we can say that the classification usually used subdivides rodents into half a dozen categories:

  • Anomaluromorphs . These involve some families of squirrels and hares.
  • Castorimorphs . These incorporate the famous beavers and other similar creatures.
  • Histricomorphs . Among which we can mention a wide group such as porcupines, mole rats, chinchillas, among others.
  • Myomorphs . Among them, we can say that there are hamsters, gerbils, rats and mice.
  • Sciuromorphs . We can say that here are the prairie dogs, squirrels and marmots.


Among the species that we can mention about rodents , we have the following:

  • Scaly Tailed Squirrel.
  • Beaver.
  • Kangaroo rat.
  • Gophers
  • Gundis.
  • African mole rat.
  • Rat of the Canes.
  • Guinea pig.
  • Chipmunk.
  • Gerbil


One of the advantages that rodents have over other mammalian groups is their ability to adapt . This means that we can find these creatures in almost all climates and habitats on the planet . It is, in fact, a group of species that have accompanied humanity in the process of colonizing very remote territories. The only sector not inhabited by rodents is precisely Antarctica .


Rodents generally have a herbivorous diet . Their diet is mainly based on the consumption of plants and seeds . However, some have a more omnivorous or opportunistic diet . This reaches the point where, in fact, some animals have a scavenger diet , that is, based on consuming remains left by other predators .


They are the groups with the highest fertile capacity on the planet. Not for nothing, it has been said that these animals have managed to survive thanks to the number of young that come out of a litter. Its reproduction is viviparous .

Rodents as pets

It is not a secret that in many countries, before a plague, many species of these animals are seen as companion animals. We have hamsters, guinea pigs, squirrels, gerbils and chinchillas.

What diseases do they cause?

But, on the other hand, we cannot forget that rodents are remembered as one of the main causes of diseases in history. Classic is the case of the famous Black Death , which left more than a third of the population of the European continent dead. Some of the diseases they can transmit are:

  • Leptospirosis.
  • Well’s disease.
  • Hantavirus.
  • Trichinosis.
  • Had.
  • Toxoplasmosis


It is known that, for many centuries, rodents have been a very important source of fear only in Europe . Cases like the Black Death are famous precisely because, it is said, they were caused by diseases brought by rodents . Currently, only in Spain   are the black rat and the common rat counted as the main pests among rodents .

Rodent control

In order to prevent the plague factor inherent in many of the rodents , with the passage of time the methods to control its appearance were refined. Some of the most common used today are:

Physical methods

Among these, we have the famous mouse traps. These can have very varied designs, all depending on what is intended to be achieved with them and how many rodents there is in a certain place.

Chemical methods

This involves the use of poisons and other substances.

Biological methods

In general, this implies that in a home, for example, rodent predators inhabit , such are the cases of many felines .


Although most people see them as bad creatures (not without reason), it should be known that rodents make up an important sector within the world’s ecosystem . Their participation is key as they are a food source for many predators . Snakes , birds , among many are creatures that use these to survive. They are also creatures that allow the transport of seeds to other places, helping plants in a similar way to bees.


  • Domestic rodents: gerbils, hamsters, rabbits and guinea pigs.
  • Field rodents : wild rabbit, common field mouse, nutria and cuis.
  • Large rodents: beavers, capybara, cabipara, porcupine, pacarana, among others.
  • Small rodents: chichilla, squirrel, common rat, among others.

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