Rhinoceros

Characteristics

General information

The visible main feature of the rhinoceroses, they are their horns on the nose. According to the species there are one or two of them. In the fossil rhinoceroses, one finds also species deprived of horn. The front horn pushes on the nasal bone, the back horn (when it exists) on before cranium. In spite of their hardness, the horns are not composed of an osseous substance, but of Kératine bound, a fibrillary protein which one also finds in the hair. The largest known horn measured 1,58 Mr.

In certain cultures of the Eastern Asia, one uses the horn of rhinoceros to make of them sculptures, cuts libatoires in particular. One also allots therapeutic effects and aphrodisiacs to the crushed horn. In Europe, in France, one uses the horn of rhinoceros to make canes of them, this is why much out of rhinoceros are killed. Between 1980 and 1984, half of the black rhinoceroses (widespread in the majority of savannas and bush of Africa, but perhaps the most threatened today) paid of their life this traffic. One distinguishes the horn from rhinoceros of the other horns thanks to the existence of hairs on the horn, of an interior which is full contrary to the ivory which is hollow. The horns of rhinoceros have a generally dark color which can transfer with clear chestnut according to the horns.

The rhinoceroses have a massive body and large and short legs. Each foot has three fingers finishing each one by a broad shoe. The skin is thick and of gray or brown color. At the Asian species, the skin at the beginning of the neck and legs if are folded that it gives the impression of a shielding.

The rhinoceroses have a low visual capacity, but this disadvantage is compensated by a subtle sense of smell and a very good hearing.

The males do not have a scrotum: the testicles are inside the body.

The female is called the rhinocère and small the rhinocéron.

Physical comparisons

Populations

Lifestyle

The rhinoceroses live normally as recluses but, in savanna, one can sometimes see small herds.

If a female is in heat, the males can come from there to fight. The winner makes his court with the female in a curious way: he marks his territory with his urine and his dejections; moreover, the two partners pursue and fight one against the other before the coupling.

After a gestation from 15 to 18 months is born small which can remain two years and half with the mother. With the birth of the following, his/her mother drives out it.

In the course of the day the rhinoceroses sleep, they are especially active in the twilight and the night.

In fact apprehensive animals avoid the men. It is when they feel threatened that they attack. Very rare, these attacks can sometimes cause serious wounds because of the power of the animal and the danger which the horn represents.

In full race, an rhinoceros can reach 45 km/h.

Rhinoceroses are often accompanied by birds by the spade-oxen kind or will hérons buff-backed herons, which perch themselves on their skin and parasites clean them. In rather rare cases, the young rhinoceroses can be the prey the large cat-like ones. The adult rhinoceroses do not have any enemy if it is not the man.

Systematic

Current species

Rhinocerotoidea ├-- Amynodontidae (†) └-- Rhinocerotida ├-- Hyracodontidae (†) └-- Rhinocerotidae ├-- Elasmotheriinae]] (†) └-- Rhinocerotinae ├-- Aceratheriini (†) └-- N.N. ├-- N.N. | ├-- Dicerorhinini | └-- Rhinocerotini └-- Dicerotini

The rhinoceroses of Asia are related between them and would have separated there is approximately 26 million years of the rhinoceroses of Africa.

Asia: The Rhinoceros of Sumatra (Dicerorhinus sumatrensis), in great danger of extinction, is the single survivor of the oldest group, the Dicerorhinini. He is more the close relative living of old the woolly Rhinocéros.

The kinds Rhinoceros (2 species) is also in danger: the the Indian Rhinoceros (Rhinoceros unicornis) and especially rarest: the Rhinoceros of Java (Rhinoceros sondaicus).

These two kinds would have separated one from the other approximately 10 million years ago.

Africa: The two African kinds, the white rhinoceros (Ceratotherium simum) and the black rhinoceros (Diceros bicornis), separated one from the other approximately 5 million years ago.

They are distinguished one from the other, inter alia, by their way of feeding. While the white Rhinocéros grazes grasses, the black Rhinocéros nourishes sheets. It is able to draw in its mouth the end of the branches thanks to its upper lip which points ahead.

Old species

At prehistoric times, the rhinoceroses had sometimes very an other appearance that their current representatives.

The giant rhinoceroses (Hyracodontidae) were with Paraceratherium (known also under the name of Baluchitherium and d' Indricotherium ) the largest known terrestrial mammals of all times. They had a long neck, were deprived of horn and lived during the Oligocène (- 30 million years).

The first known parents of the rhinoceroses are fossils of the Eocene higher. These Amynodontidae was already as large as the current rhinoceroses, but did not have a horn and probably nourished watery plants (from where their German name “Wassernashörner” literally: water rhinoceros).

The true rhinoceroses (Rhinocerotidae) separated in two lines: the Elasmotheriinae whose most known kind Elasmotherium still lived at the last glacial period and was characterized by an immense, long horn of 2 m, and the Rhinocerotinae with the three kinds mentioned above. The prehistoric men of the European West côtoyé 4 species of rhinoceroses which had survived three difficult glaciations, but that they undoubtedly contributed to make disappear.

The woolly Rhinocéros of the glacial era is arranged among the Dicerorhinini, it is thus related with the rhinoceroses of Sumatra.

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