There are two subclasses of mammals - primary and real animals. The first group includes monotremes. They differ from the second in that they lay eggs, but the young, hatched from them, feed on milk. The real animals are divided into two supra-divisions - marsupials and placental mammals.
The former differ from the latter in that during pregnancy the female does not form a placenta, a temporary organ providing communication between the parent and the daughter's body. But these animals have a bag that is designed to carry a cub that is born incapable of independent living. This nadryad includes only one detachment - the Marsupials. And to the placental belong to all the other units, such as pedigree, pinnipeds, carnivores, primates, chiropterans, etc.
Classification
Marsupial mammals in the systematics of animals occupy an ambiguous position. On some systems, this group of organisms is a detachment, and on others - the infraclass. For example, take the koala. In one of its variants, its place in the classification looks like this:
- Domain - Eukaryotes.
- Kingdom - Animals.
- Type - Chord.
- Subtype - Vertebrates.
- Class - Mammals.
- Detachment - Marsupial.
- Family - Wombat.
Alternatively, like this:
- Domain - Eukaryotes.
- Kingdom - Animals.
- Type - Chord.
- Subtype - Vertebrates.
- Class - Mammals.
- Infraclass - Marsupial.
- Detachment - Dvuretstsovy marsupials.
- Suborder - Wombat
- Family - Koalovye.
Characteristics of marsupial mammals
Most species of this order are endemic, that is, they live only in a particular locality. Most often it is Australia. Almost all the marsupial mammals of the planet inhabit this continent. Most marsupials are listed in the Red Book.
Also, representatives of this group of animals inhabit New Guinea and are found in South and North America. Marsupial mammals are subdivided into nine families: Opossum, Marsupial anteaters, Bandicoot, Predatory Marsupial, Coenolest, Possuma, Kangurov, Wombat, Marsupial moles. The most ancient and most primitive of the families of this order are Opossums, from which all other animals of this group originated. Let's take a closer look at each family and its representatives.
Marsupials outside of Australia
The oldest family is Opossums. Animals belonging to this group are one of the few marsupials that live outside of Australia.
They are common in the territory of America. Such marsupial mammals, such as smoky, eastern, brownie, velvet, and American opossums belong to this family. These are small animals, about 10 cm long, with a long tail and thick hair. They are predominantly nocturnal, eat insects and a variety of fruits. These animals are good at pretending to be dead in case of danger. Also outside Australia, in South America, some species of kangaroos live, for example, wallabies.
Representatives of the order Marsupials living in Australia
These include most of the animals in this group. The most famous of them are the mammals of the kangaroo family. Representatives such as the big red kangaroo, the bear kangaroo, the long-eared kangaroo, the western gray kangaroo, etc. belong to it. They are large animals with a large tail that serves as an additional support for them. These mammals have underdeveloped forepaws, but strong hind legs, which allows them to move, jumping long distances. The main diet of kangaroo consists of plants. The young of these animals are born only three centimeters long, and the gestation of the female is only about 30 days (up to 40, depending on the species). In addition, kangaroo rats belong to this family. No less common in Australia are wombats. These are small animals whose muzzle is somewhat bearish, but their teeth are almost the same as those of rodents.
They feed wombats with the roots of various plants, all kinds of fruits and seeds. Their front paws have large claws, which allows them to dig more effectively, because wombats are one of the animals that spend most of their lives in burrows underground. The marsupial moles are characterized by similar behavior - these are small animals that eat beetle larvae and seeds. They also differ in that they do not have a constant body temperature.
Marsupials listed in the Red Book
The most famous of these are koalas. They are on the verge of extinction, since the only product they eat is eucalyptus leaves, and not all of them - only 100 of 800 species of this plant are eaten with koalas. .
The largest and smallest animals of the order are Marsupials
The largest mammal of this group is the large gray kangaroo, and the smallest is the possum-honey badger, which feeds on pollen of plants. The largest marsupial animal lives in South and Western Australia. His weight can reach fifty kilograms, and height - a little more than a meter.
The smallest marsupial mammal, Acrobates pygmaeus, lives only in Australia. Its weight rarely exceeds fifteen grams. This animal has a long tongue, it is necessary in order to make it easier to get pollen and nectar of plants. Also one of the smallest marsupial animals can be called a marsupial mouse, whose weight is also about ten grams.
Features of mammals
This class of vertebrate animals belongs to the four-legged superclass, in which there are about 5.5 thousand species, including “Homo sapiens”. The main feature of the representatives of the group "Mammals animals" is baby milk feeding.
In addition, there are the following signs:
- warm-bloodedness
- live birth,
- the body is covered with hair, sweat and sebaceous glands are developed, horn formations,
- the skull has a zygomatic arch
- the spine is clearly divided into five sections,
- platinum-type vertebrae,
- subcutaneous muscles are strongly developed, there is a diaphragm,
- highly developed nervous system that allows you to quickly respond to stimuli from the external environment,
- the special structure of the organ of hearing
- lungs have alveolar structure,
- the heart is four-chamber, the blood circulation is divided into two circles,
- unique structure of the jaws and teeth.
The physiology of mammals is not very different from other four-legged representatives, but due to the high development of some organ systems, this class is considered to be the highest highly organized among animals.
The Latin name for this class is Mammalia, which was derived from the Latin “mamma” - chest, udder. The Russian word "mammals" means - feeding with milk.
Spread
Class representatives can be found everywhere. The only places where there are no mammals are the deep ocean and Antarctica, although seals and whales can be found off its coast.
Many subtypes are limited in distribution due to attachment to environmental conditions. For many animals, temperature, soil and orographic conditions, and food availability are important.
Description of mammals
All members of the class are quite diverse in appearance. The traditional structure of the body, which consists of the head, neck, torso, two pairs of limbs and tail, varies in the ratio of shapes and sizes. So, a striking example of such variations can be a long neck of a giraffe, and the lack of a neck in whales.
Fig. 2. External structure.
The "Bats" detachment is very different from other mammals due to the transformation of the front limbs into wings. Due to this, in the national classification of bats they were referred to birds.
Record holders in size and body weight are: dwarf polytice (weight up to 1.7 g, length up to 4.5 cm), savanna elephant (weight up to 5 tons, height at shoulders up to 4 m), blue whale (length 33 m, weight - up to 1.5 tons).
The list of mammals in Russia includes about 300 species. You can see their list in the following table:
photo source
Nambat - marsupial animal, has stripes on the back, dark stripes around the eyes and a bushy tail (also known as the striped anteater). The basis of the diet nambat constitute termites.
Spotted Marshhead
photo source
Spotted Marshhead also known as marsupial cat. They have a pink nose and white spots on the back. In females, the bag is formed only in the mating season.
Marsupial mole
Marsupial mole - marsupial animal, very similar to ordinary moles in appearance and habits. These creatures dig tunnels underground, hunting for insects and worms. Females have bags that open back and only two nipples (this means that they can only give birth to two young at a time).
Dvoreztsovy marsupial animals - A number of marsupials, which include kangaroos, wallabies, possums, koalas and wombats. They have two large front teeth in the lower jaw. The second and third toes of the hind legs of these animals are fused. They are predominantly herbivores.
Some interesting facts about marsupials
Body sizes marsupials range from a few centimeters to 1.5 meters. The smallest marsupial animal on Earth is a long-tailed marsupial mouse.. The length of its body is from 80 to 100 mm, tail - from 180 to 210 mm .. The largest marsupial animal is considered the big red kangaroo.. Adults kangaroos can reach 2 m tall. The baby giant kangaroo stays in the mother's bag for about 235 days.
