Ornithorynque

The ornithorynque is small a semi-watery Mammifère, that one does not find that in the east of the Australia. It is one of the five monotrèmes, the only mammals which lay egg S instead of giving rise to the small alive ones (the four others are echidna S).

Description

The ornithorynque one ( Ornithorhynchus anatinus ) resembles a beaver: the body and the tail, broad and flat, covers of Fur maroon, but it is equipped with webbed feet and a large rubbery muzzle which made it indicate in English by “duck-billed platypus” (“flat foot with Bec of Canard”). Its tail measures from 10 to 15 cm. The males are usually of a third larger than the females, but their size, between 40 and 50 cm on average, varies considerably from one area to another, without it being related to the climate.

The ornithorynque male carries pivots poisonous to the ankle S. Its poison is not mortal for the human ones but causes atrocious pains and puffiness which can last several months. Venom can be mortal for a Chien or small pets.

He is night bird and savage, almost imperceptible. But it is perhaps its timidity which preserved this aberrant prehistoric creature. From aspect mid- Reptile semi-mammal, the ornithorynque one passed a long time for a dream. Today, the scientists see in him one of the animals best adapted Australian continent.

There spends on average 2 hours per minimum day in water and can remain immersed during short periods from 12 to 15 minutes. Doubled fat fabric, the fur of ornithorynque enables him to face the coldest rivers of Australia. It supports heat less better and disappears at the end of 7 minutes of exposure to the sun by 35°C. After its bath, he likes to regain his burrow without to have wiped his peeling, which formerly was very snuffed furriers for its insulating qualities and its large smoothness.

A fold of skin sealing at the same time its eyes and its ears, in diving, the ornithorynque one can detect its preys only with its nozzle.

It is an excellent swimmer and it passes the essence of its time in water. There can remain 5 minutes in diving. It then keeps the eyes and the ears hermetically closed and makes use of its other directions to move but it often detects its preys thanks to detectors of electric fields located on its nozzle (to see further) . The four legs of ornithorynque are webbed. When he swims, he is propelled with his legs of front; its tail and its legs postpone help it to move but not to be propelled.

Distribution and habitat

The ornithorynque one is a semi-watery animal, alive in the small rivers on a territory extending from the highlands of Tasmanie (devastating there, it is said, of the breedings of Truite S) and from the the Australian Alps to the tropical rain forests of the coastal Queensland as to far towards north as the bottom of the peninsula of the Cape York. Inside the country, its distribution is not well-known: it died out in Australia of the south (except for a population introduced on the island Kangourou) like in most of the Bassin Murray-Darling, probably because of a deterioration of the quality of the Eau caused by the Défrichement and the intensive Irrigation. Its distribution is random along the various coastal rivers: it seems absent from certain relatively salubrious rivers whereas it is maintained in the different one passably degraded (bottom Maribynong for example).

Out of water, the ornithorynque lodging in small a narrow Burrow, of oval section, almost always in the banks, not far from the level of water, and often hidden by the protective tangle of roots. To reproduce, the females dig a burrow much broader and more worked out, length of 20 Mètre S and blocked by stoppers with regular intervals. At the end of the tunnel, the reeds which they bring are used as Nid.

At first sight, thanks to its watery lifestyle, in burrow and far from the inhabited areas, the ornithorynque one does not seem in immediate danger of extinction: it is nevertheless indexed like vulnerable. Like all the aquatic animals, it is indeed very sensitive to the Pollution of water.

Food

The ornithorynque one is carnivorous. It nourishes Ver S, of Larve S of Insecte S, of Crevette S of fresh water and crayfish S which it unearths in the bed of the rivers with its muzzle or which it catches while swimming. The skin recovering its nozzle is very sensitive and allows him to drive out its food without having to use the sight. The ornithorynque one is the only mammal known to have the direction of the électroperception, i.e. it can partly locate its preys thanks to the detection of their electric field: it perceives the vibrations of its preys by receivers of its nozzle.

Reproduction

Like all the Monotrèmes, the ornithorynque female is not confined of small alive, but lays eggs in the nest. It has only one same opening (Cloaque) for the reproduction and to expel its excrements, which is characteristic of the family of the birds and reptiles.

When the eggs hatch, the small emergent one and cling to the mother. As for the other mammals, the female nurses its small. She does not have an apparent nipple but emits her Lait through small openings in the skin. The small ornithorynques ones lick the milk which runs of their mother when it is extended on the back.

The Sexe of the mammals is determined by a pair of chromosomes; the Femelle has two Chromosome S X, and the male X and a Y. In the birds, the mechanism is similar but the male is ZZ and female ZW. In 2004, thanks to fluorescent markers , the researchers Jenny Graves and Frank Grützner, Australian National university of Canberra, highlighted that the ornithorynque one has five pairs of chromosomes. The female is characterized by a sequence while the male has a sequence XYXYXYXYXY. Moreover, the chromosomes of the beginning of the chain have Gène S commun runs with the mammals, while those of the end divide genes with the birds.

History of its discovery

The first scientific description of the animal is due to George Kearsley Shaw (1751-1813) in Naturalist' S Miscellany , in 1799, but this publication was regarded as a hoax by the scientists of its time. Other work had to be awaited, in particular those of John Gould (1804-1881), so that one starts to admit his existence.

The whole world discovered the ornithorynque one in 1939 when the magazine National Geographic published an article describing the efforts to study it and to maintain it in captivity (task very difficult: the first place where he survived - and always one of only - is the Healesville Sanctuary in the Victoria). Well few young people could be high until now: the first range born in captivity took place in 1944. The principal reference is due to Tom Grant.

The scientific name ornithorhynchus literally means “nose of bird” in Greek and anatinus returns to “Latin duck”. The common noun English platypus (“flat foot” - flat foot) was originally given to him in the classification of Carl von Linné (1707-1778) but it was discovered since this name was already allotted to a Invertébré, a Coléoptère of the family of the Platypodidae, super-family of the Curculionoidea, by the entomologist Johann Friedrich Wilhelm Herbst (1743 - 1807).

Etymology

In 1803, the geologist Barthélemy Faujas of Saint-Bottom uses the C-W communication ornithoringue . Georges Vat, uses the double ornithorhynque orthography and ornithorinque in the Volume the 3 Leçons of comparative anatomy , respectively pages 107 and 243.

See too

Fauna of Australia

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