Mammals are the most highly developed and progressive creatures of all that inhabit the earth. The number of known and living species is about 5500, and when you consider those that have become extinct - 20 thousand. According to several modern taxonomists, the class unites 26-29 squads. Mammalia representatives are ubiquitous.
The most numerous detachment of mammals are rodents. It’s a joke, but now zoologists describe 2277 species, and this is more than half of all animals and first animals. Rodents spread throughout the planet, with the exception of Antarctica and some islands. They are not only carriers of dangerous diseases and pests, but also a valuable source of fur, an object of fishing and scientific research, etc. Their role in ecosystems is ambiguous and multifaceted, while the knowledge of most people is limited only to “acquaintance” with domestic animals. mice and rats.
general characteristics
Rodentia is the Latin name for the largest detachment of mammals, literally it translates as "swallow, bite." A characteristic feature of all rodents is a pair of large incisors on the lower and upper jaws, as well as a diastema, i.e., a large gap between them is disproportionate.
Rodents do not differ in large sizes. The smallest mice are from 5 cm in length, the largest are capybaras (pictured below), up to 130 cm, but usually about 50 cm. Moreover, the tail is often much longer than the body. In some species, for example, guinea pig, it is absent. The shape of the limbs and body depends on lifestyle and can vary greatly. In jumping forms (jerboas) hind legs are strongly developed. Burrowing species have a roll-shaped body shape and have claws on their forelimbs (moles, shrews). Planning species (flying squirrel) have a lateral skin fold.
As already mentioned, a distinctive feature of the representatives of the largest detachment in the class of mammals is a pair of incisors on the lower and upper jaws. Cutters constantly grind and grow, they have no roots. In particular, in beavers (in the photo below), their growth rate reaches up to 0.8 mm per day. Fangs are absent and incisors from small molars are separated by distance - diastema.
Lifestyle & Nutrition
Most often, rodents are active at night or at dusk. They live both in large groups of up to hundreds of individuals (naked mole rat), and individually. They mastered all living spaces, including air.
The bulk of the species of the largest detachment of mammals is herbivorous animals. Depending on the season and habitat, they eat all parts of the plant: bark, leaves, stems, seeds, roots and fruits. There are omnivorous species (dormouse, mice, diggers), the diet of which includes insects, worms, small vertebrates, bird eggs.
The value of rodents
More than half of the species of mammals on the planet are rodents. It is logical that they play a huge role in ecosystems. Rodents are an important food source for predators; colonies are constantly replenished due to rapid reproduction. Ordinary rats are ready to mate immediately after birth, and the pregnancy lasts about 25 days.
Representatives of the largest detachment of mammals have been accompanying humans since time immemorial, therefore their significance in our life is very diverse:
- Research field. The ease of maintenance and high breeding rate have made rodents suitable animals for laboratory research.
- Disease carriers (bubonic plague, listeria, toxoplasmosis, tick-borne encephalitis, etc.).
- Pets. Many types of rodents are kept at home: rats, mice, hamsters, chinchillas, guinea pigs.
- Source of fur. Many rodents are game animals due to their light and pleasant to the touch fur (chinchilla, squirrel).
- Pests of crops.
Rodents in the Red Book
In Russia, the following rodents are listed in the Red Book: tarbagan, beaver, black-capped marmot, Manchurian zokor, giant mole rat, yellow pestle. These species are recognized as endangered and endangered. This is largely due to human activities.
Sonya (shelf, garden and hazel or mouslovka), common flying squirrel (pictured), common hamster and speckled ground squirrel are rodents listed in the Red Book of Belarus. The largest mammalian order in the Republic of Belarus is represented by only 26 species, and six of them need protection.
In Ukraine, the Red Book includes: ground squirrel (Podolsk, European and speckled), mole rat (Bukovinsky, Podolsky, sand and white-toothed), big jerboa, common henchman, mouse (Stranda, steppe, dark and forest), hamster (gray and ordinary) , field vole (Tatra and snow), mole vole , common pestle, steppe pest, garden dormouse.