The British thought the brown rat (Rattus norvegicus) came in merchant ships from Norway, and therefore call it the Norway rat. But the truth is: This not very appreciated rodent is a native of China and has spread to every single corner of our planet except Antarctica.

Originally a forest animal, brown rats easily adapted their ways to live near rapidly expanding human settlements where food and shelter are almost unlimited.

The brown rat has a large and heavy body that can reach up to 40 cm in length and almost 500 grams in weight. A brownish bushy fur covers the body, except over the ears and tail, which is usually shorter than the body. The brownish color gets lighter on the underside.

Their reproduction rates are impressive compared with other mammals, which is the main reason for their outstanding success in populating the world. Females can copulate with several males for as many as 500 times during a six–hour period, then produce litters of up to seven or eight baby rats. They are ready to give births again after a very short period, being able to reproduce six or seven times a year. Each female is capable of giving birth to at least 50 or 60 new rats every year, not to mention that newborns will be ready to reproduce on their own in just about three or four months.

Brown rats are very social, to the point of even sharing nests and taking care of babies that are not their own. They can feed on basically everything, from seeds and fruits to smaller animals like reptiles, bird´s eggs and even fish. They also are very good at scavenging and are considered to be opportunistic eaters. They basically eat whatever is available, which comes in very handy when they live near humans.

Rats tend to be considered disgusting and unwanted animals; however, from an ecological point of view, they play an important role in the ecosystem. They are a key prey species for many predators such as snakes and birds, and they help spread seeds and loosen soil when digging holes, which helps with proper soil health.

Learning about this amazing mammal will help us understand how important it is to preserve a proper dynamic ecosystem where all species are protected since they help prevent any one species from developing an uncontrolled growth rate in our beautiful city.