Rodents

Rodents - Rats - Mice - Mouse

Forty percent of mammal species are rodents. They are found in large numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, porcupines, beavers, guinea pigs, and hamsters. Rodents are identified by a single pair of continuously growing incisors in each of the upper and lower jaws which must be kept short by gnawing. They gnaw wood, break into food, and bite predators. Mostwill eat seeds or plants, though some have more varied diets. Some species have historically been pests, eating seeds stored by people and spreading disease.

Rat

Rats. The best-known rat species are the black rat (Rattus rattus) and the brown rat (Rattus norvegicus).This group is known as the Old World rats or true rats, and originated in Asia. Rats are bigger than most Old World mice, which are their relatives, but seldom weigh over 500 grams (1.1 lb) in the wild. Rats serve as zoonotic vectors (carriers) for certain pathogens and cause disease, such as Lassa fever, leptospirosis and Hantavirus infection. However, the rat is almost never directly responsible for the pathogen. Though it is commonly believed that rat is responsible for the outbreak of bubonic plague, the European citizens are to blame. After throwing waste into the street the rats moved where it was easy to find food. The rat flea then spread the plague from there. It is estimated that as many if not more rats died from the plague than people.

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  Norwegian Rat / Norway Rat or Brown Rat
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  Roof Rat

Mice - Mouse

Mice. A mouse (plural: mice) is a small mammal in the rodent family, characteristically having a pointed snout, small rounded ears, and a long naked or almost hairless tail. The best known species is the common house mouse (Mus musculus). It is also a popular pet. Certain kinds of field mice are also common. The mouse is eaten by large birds such as hawks and eagles. They are known to invade homes and buildings for food and occasionally shelter. Cats, wild dogs, foxes, birds of prey, snakes and even certain kinds of arthropods have been known to prey heavily upon mice. Because of its adaptability to almost any environment, the mouse is one of the most successful mammalian genera living today. They at times be vermin, damaging and eating crops, causing structural damage and spreading diseases through their parasites and feces. In North America, breathing dust that has come in contact with mouse excrement has been linked to hantavirus. Nocturnal animals, mice compensate for their poor eyesight with a keen sense of hearing, and rely especially on their sense of smell to locate food and avoid predators. There are other reasons why mice are used in laboratory research. Mice are small, inexpensive, easily maintained, and can reproduce quickly. Several generations of mice can be observed in a relatively short period of time. Mice are generally very docile if raised from birth and given sufficient human contact. Certainc strains however have been known to be temperamental. Mice and rats have the same organs in the same places, just different proportions.