, , ,

If you have Rat problems Call: 952449591 ask for Gray





Tree rats are endemic in spain they make look cute and cuddly, but they certainly are not.Take a look at this video. Rata Parada or the Brown Rat, has adapted in spain, and is more sleek than the ones that you see in the UK,although they are the same breed.Here are some facts.


Geographic Range

Norway rats (Rattus norvegicus) are originally native to northern China. Following a series of introductions, the species had found its way to Eastern Europe by the early eighteenth century. By the year 1800, they occurred in every European country. Records show the first sighting of R. norvegicus in the New World occur in the 1770’s as ship stowaways. Today, Norway rats (also known as brown rats) can be found on every continent of the world except Antarctica. (Nowak and Paradiso, 1983Silver, 1927)


In Asia, R. norvegicus was native to forests and brushy areas. Today, however, Norway rats find preferred habitat to be alongside the rapid expansion of the human population. Nearly every port city in the world has a substantial population of these rodents. They occupy a variety of habitats including garbage dumps, sewers, open fields and woodlands, basements, and nearly anywhere else that food and shelter might be found. Anywhere that humans are located, R. norvegicus will most likely follow. (Hamilton, 1998Nowak and Paradiso, 1983Parker, 1990)

Physical Description

Rattus norvegicus is a rather large member of the mouse family. On average, these rats reach nearly 400 mm nose-to-tail, and weigh 140 to 500 g. Males are usually larger than females. In natural populations, these rats are covered with coarse, brownish fur (sometimes splotched with black or white hairs) on their dorsal surface, which usually lightens to a gray or tan color nearing the underside. Various strains of these rats bred in captivity may be white, brown, or black. The ears and tail are bald. The length of the tail is shorter than the length of the body. Molars are lophodont and the dentary is 1/1-0/0-0/0-3/3. The ears of Norway rats are typically shorter than those of related species, and do not cover up the eyes when pulled down. Norway rats can be easily mistaken for black rats, however, the temporal ridges of the Norway rat are straight, whereas those of the black rat are curved. (Nowak and Paradiso, 1983Avalos and Callahan, 2001Calhoun, 1962Nowak and Paradiso, 1983Parker, 1990)

  • Sexual Dimorphism
  • male larger
  • Range mass

    140 to 500 g

    4.93 to 17.62 oz

  • Average mass

    400 g

    14.10 oz

  • Average length

    399 mm

    15.71 in

  • Average basal metabolic rate

    1.404 W



The mating system of R. norvegicus is best described as polygynandrous. Social animals, Norway rats tend to breed in large groups. Once a female enters her six-hour estrus period, she may mate as many as five-hundred times with competing males. (Parker, 1990)

Although not technically a seasonal breeder, a mating increase occurs in the warmer months of the year. An average female is capable of giving birth approximately seven times per year. Around 18 hours after giving birth, females experience postpartum estrus, and mate again. This reproductive function is responsible for the huge birthrates of Norway rats, which can reach 60 young each year per female. After a short gestation period of 22 to 24 days, the litter of approximately 8 pups is born. The young are very small and underdeveloped. It takes 14 to 17 days for the young’s eyes to open. Newborns weigh an average of 5 grams and are milk-fed until weaning occurs at 3 to 4 weeks, and the young then leave the nest. (Barnett, 1963Calhoun, 1962Parker, 1990)

Often, the litters of numerous females will occupy the same nest, and all the young are cared for by the adults, regardless of who the true mothers are. This communal care makes the species something of a cooperative breeder. (Parker, 1990)

Males usually reach sexual maturity at 3 months and females at 4. However, it is usually the female who mates first because competition for mates among males prevents the smaller, less-dominant individuals from succeeding immediately. Rattus norvegicus is capable of mating for up to two years. for any pest control problem Call: 952449591 www.localpest.es