Rats have poor eyesight, relying more on their hearing and their excellent senses of smell, taste, and touch. Some individuals may be active during daylight hours when rat populations are high. They usually become active about dusk, when they begin to seek food and water.
In the United Kingdom, brown rats are an important reservoir for Coxiella burnetii, the bacterium that causes Q fever, with seroprevalence for the bacteria found to be as high as 53% in some wild populations. Similar to other rodents, brown rats may carry a number of pathogens, which can result in disease, including Weil’s disease, rat bite fever, cryptosporidiosis, viral hemorrhagic fever, Q fever and hantavirus pulmonary syndrome. In fact it is common for breeding wild brown rats to weigh (sometimes considerably) less than 300 g (11 oz) Stories of rats attaining sizes as big as cats are exaggerations, or misidentifications of other rodents, such as the coypu and muskrat. Exceptionally large individuals can reportedly reach 900 to 1,000 g (32 to 35 oz) but are not expected outside of domestic specimens. Adult body weight averages 350 g (12 oz) in males and about 250 g (9 oz) in females. The length is commonly in the range of 20 to 25 cm (8 to 10 in), with the tail a further 18 to 25 cm (7 to 10 in), thus being roughly the same length as the body. The brown rat is a rather large true murid and can weigh twice as much as a black rat and many times more than a house mouse. The fur is coarse and usually brown or dark grey, while the underparts are lighter grey or brown.
0 kommentar(er)
