rodent, (order Rodentia), any of more than 2,050 living species of mammals characterized by upper and lower pairs of ever-growing rootless incisor teeth. Rodents are the largest group of mammals, constituting almost half the class Mammalia’s approximately 4,660 species.
They are indigenous to every land area except Antarctica, New Zealand, and a few Arctic and other oceanic islands, although some species have been introduced even to those places through their association with humans.
This huge order of animals encompasses 27 separate families, including not only the “true” rats and mice (family Muridae) but also such diverse groups as porcupines, beavers, squirrels, marmots, pocket gophers, and chinchillas.
All rodents possess constantly growing rootless incisors that have a hard enamel layer on the front of each tooth and softer dentine behind. The differential wear from gnawing creates perpetually sharp chisel edges.
Rodents’ absence of other incisors and canine teeth results in a gap, or diastema, between incisors and cheek teeth, which number from 22 (5 on each side of the upper and lower jaws) to 4, may be rooted or rootless and ever-growing, and may be low- or high-crowned.
The nature of the jaw articulation ensures that incisors do not meet when food is chewed and that upper and lower cheek teeth (premolars and molars) do not make contact while the animal gnaws. Powerful and intricately divided masseter muscles, attached to jaw and skull in different arrangements, provide most of the power for chewing and gnawing.
Rodent Control Methods: Trapping, Exclusion, Bait Boxes, and Sanitation
- Trapping is the safest and most effective method for eliminating rodents from your property. …
- Exclusion ensures that mice and rats are prevented from gaining access to your home or business by sealing up potential access points.
Ways To Get Rid of Rodents, Rats & Mice Naturally And Humanely
- Remove all food sources. Mice only need small amounts of food each day. …
- Get rid of nesting materials. …
- Seal entry points. …
- Use natural mouse repellent. …
- Get a cat. …
- Try live traps. …
- Use sound. …
- Use essential oils.
General features of Rodents
The range in body size between the mouse (18 grams [0.64 ounce], body 12 cm [4.7 inches] long) and the marmot (3,000 grams, body 50 cm long) spans the majority of living rodents, but the extremes are remarkable. One of the smallest is Delany’s swamp mouse (Delanymys brooksi), associated with bamboo in the marshes and mountain forests in Africa.
It weighs 5 to 7 grams, and the body is 5 to 6 cm long. The largest is the capybara (Hydrochoerus hydrochaeris) of Central and South America, which weighs 35 to 66 kg (77 to 146 pounds) and stands 50 to 60 cm at the shoulder, with a body 100 to 135 cm long. Some extinct species were even larger, attaining the size of a black bear or small rhinoceros.
The largest rodent ever recorded, Josephoartigasia monesi, lived some two to four million years ago, during the Pleistocene and Pliocene epochs; by some estimates it grew to a length of about 3 metres (10 feet) and weighed nearly 1,000 kg.
Importance of Rodents to humans
Rodents have lived on the planet for at least 56 million years and modern humans for less than one million, but the consequences of their interactions during that short overlap of evolutionary time have been profound.
For rodents, early humans were just another predator to avoid, but with Homo sapiens’ transition from nomadic hunting and gathering to sedentary agricultural practices, humans became a reliable source of shelter and food for those species having the innate genetic and behavioral abilities to adapt to man-made habitats.
The impact of these species upon human populations ranges from inconvenient to deadly. Crops are damaged before harvest; stored food is contaminated by rodent waste; water-impounding structures leak from burrowing; and objects are damaged by gnawing.
Certain species are reservoirs for diseases such as plague, murine typhus, scrub typhus, tularemia, rat-bite fever, Rocky Mountain spotted fever, and Lassa fever, among others. Only a few species are serious pests or vectors of disease (see house mouse and rat), but it is these rodents that are most closely associated with people.