Macropodidae

The Macropodidés (or Macropodidae ) form one of marsupial which includes/understands the Kangourou S, the wallabies, the Petrogale S, the Dendrolague S, the Thylogale S and some other species. They live all either in Australia, or in New Guinea, or in Indonesia. 53 species existed in Australia before the arrival of Europeans, 6 disappeared and 11 strongly decreased of number. A certain number of species had already disappeared with the arrival from the aboriginals (Simothanurus, Propleopus, Macropus Titan, etc…).

The macropodidae are herbivorous animals: some nourish sheets or stems but the majority graze grass and are equipped with teeth adapted to their food, enabling them to cut grasses then to crush fibers. In general the Macropodidae have a line of powerful Incisive S, not of Canine S and thus a free interval before the Molaire S. the molars do not appear all at the same time but a new generation appears once the preceding series was worn by the abrasion of the plants and fell. The majority of the marsupials have four generations of molars thus and when the last generation became out of use, the animals die of hunger.

Like the placental Ruminant S of the hemisphere northern (sheep, Bovidae, etc….), the macrpodidae have a special digestive system which uses strong quantities of bacteria or mushrooms to degrade fibers in the first pocket of their stomach. If the details of the organization of their digestive system are rather different, the results are rather similar.

The various Macropodidae have very variable sizes but the majority have very large back legs and a long and muscular tail. The term macropodidé drift of the Greek and means " with long pieds" ; the majority have the very long ones and narrow back legs with toes with the specific measure: the fourth toe is very long and very powerful, the fifth is less than the fourth; the second and the third toes are amalgamated, first is absent. The front legs are short and have five separate fingers. Some Macropodidae have only seven bones on the level of the wrist (" carpe") instead of the eight usual ones by fusion of the Scaphoïde with the semi lunar. All have relatively small heads with large ears except for the arboricolous kangaroos which need to be able to move quickly between the branches of the trees.

With the birth the young people are very small and the marsupium opens forwards.

Moreover, there is a bond between the breathing and the jumps of the kangaroos. When the back legs leave the ground, the air is expelled of the lungs by a kind of piston internal; when they return forwards before resting, the lungs fill by consuming very little energy.

Studies on the kangaroos and the wallabies showed that, in addition to low fuel consumption of energy necessary to move while jumping, the increase speed is accompanied by a tiny extra effort (which is not at all comparable with that which the other animals like the horses, the dogs and even the men need). In the same way an increase in weight is accompanied by a weak overconsumption of energy what is important for the femellesqui cart their small in their marsupium.

The possibility for the large Macropodidae of surviving with a food of bad quality, with low energy value and of being able to travel at long distances at high speed without consuming much energy (to reach a food fraiche, a water point or to escape predatory) was a crucial factor for the success of their evolution on a continent which, with the weak fertility of its grounds and weak, unforeseeable pluviometry offers very limited possibilities of development.

Classification

The macropodidae are divided into two pennies families:

  • the Sthenurinae which were largely widespread with the Pléistocène and which are represented more only by only one species considered as vulnerable: the Hare wallaby striped
  • and the Macropodinae which gather about sixty remaining species.

Random links:Aupaluk (Scandinavian village) | Toilets sports shirt with the Olympic Games of 1988 | Kelly Rowan | Liam | Passport of service | SAT