Lama (genus)
|
|
| Llamas | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scientific classification | ||||||||||||
| ||||||||||||
| Species | ||||||||||||
Lama, the modern genus name for a small group of closely allied animals, which, before the Spanish conquest of the Americas, were the only domesticated ungulates of the continent. They were kept not only for their value as beasts of burden, but also for their flesh, hides, and wool. See individual species articles at:
Classification
Although they were often compared by early writers to sheep and spoken of as such, their affinity to the camel was very soon perceived. They were included in the genus Camelus in the Systema Naturae of Linnaeus. They were, however, separated by Cuvier in 1800 under the name of Lama along with the Alpaca and the Guanaco. Vicuņas are in genus Vicugna. The animals of the genus Lama are, with the two species of true camels, the sole existing representatives of a very distinct section of the Artiodactyla or even-toed ungulates, called Tylopoda, or "bump-footed," from the peculiar bumps on the soles of their feet, on which they tread. This section thus consists of a single family, the Camelidae, the other sections of the same great division being the Suina or pigs, the Tragulina or chevrotains, and the Pecora or true ruminants, to each of which the Tylopoda have more or less affinity, standing in some respects in a central position between them, borrowing as it were some characters from each, but in others showing great special modifications not found in any of the other sections.
The discoveries of a vast and previously unsuspected extinct fauna of the American continent of the Tertiary period, as interpreted by the palaeontologists Leidy, Cope, and Marsh, has thrown a flood of light upon the early history of this family, and upon its relations to other mammals. It is now known that llamas at one time were not confined to the part of the continent south of the Isthmus of Panama, as at the present day, for their remains have been abundantly found in the Pleistocene deposits of the region of the Rocky Mountains, and in Central America, some attaining a much larger size than those now existing.
Many camel-like animals exhibiting different generic modifications and a gradual series of changes, coinciding with the antiquity of the deposits in which they are found, have been traced from the thoroughly differentiated species of the modern epoch down through the Pliocene to the early Miocene beds. Their characters having become more generalized, they have lost all that especially distinguishes them as Camelidae: they are merged into forms common to the ancestral type of all the other sections of the Artiodactyles.
Hitherto none of these annectant forms have been found in any of the fossiliferous strata of the Old World; it may therefore be fairly surmised (according to the evidence at present before us) that the Americas were the original home of the Tylopoda, and that the true camels have passed over into the Old World, probably by way of north Asia. Gradually driven southward, perhaps by changes of climate, and having become isolated, they have undergone further special modifications. Meanwhile, those members of the family that remained in their original birthplace have become, through causes not clearly understood, restricted solely to the southern or most distant part of the continent. There are few groups of mammals for which the palaeontological history has been so satisfactorily demonstrated as the llama.
Characteristics
The following characters apply especially to llamas. Dentition of adults:-incisors 1/3 canines 1/1, premolars 2/2, molars 3/2; total 32. In the upper jaw there is a compressed, sharp, pointed laniariform incisor near the hinder edge of the premaxilla, followed in the male at least by a moderate-sized, pointed, curved true canine in the anterior part of the maxilla. The isolated canine-like premolar which follows in the camels is not present. The teeth of the molar series which are in contact with each other consist of two very small premolars (the first almost rudimentary) and three broad molars, constructed generally like those of Camelus. In the lower jaw, the three incisors are long, spatulate, and procumbent; the outer ones are the smallest. Next to these is a curved, suberect canine, followed after an interval by an isolated minute and often deciduous simple conical premolar; then a contiguous series of one premolar and three molars, which differ from those of Camelus in having a small accessory column at the anterior outer edge.
The skull generally resembles that of Camelus, the relatively larger brain-cavity aud orbits and less developed cranial ridges being due to its smaller size. The nasal bones are shorter and broader, and are joined by the premaxilla.
- cervical 7,
- dorsal 12,
- lumbar 7,
- sacral 4,
- caudal 15 to 20.
Ears are rather long and pointed. There is no dorsal hump. Feet are narrow, the toes being more separated than in the camels, each having a distinct plantar pad. The tail is short, and fur is long and woolly.
In essential structural characters, as well as in general appearance and habits, all the animals of this genus very closely resemble each other, so that the question as to whether they should be considered as belonging to one, two, or more species has been one which has led to a large amount of controversy among naturalists.
The question is complicated by the circumstance of the great majority of individuals which have come under observation being either in a completely or partially domesticated state. Many are also descended from ancestors which have previously been domesticated; a state which tends to produce a certain amount of variation from the original type. It has, however, lost much of its importance since the doctrine of the distinct origin of species has been generally abandoned. The four forms commonly distinguished by the inhabitants of South America are recognized by some naturalists as distinct species, and have had specific designations attached to them, though usually with expressions of doubt, and with great difficulties in defining their distinctive characteristics.
The Llama and Alpaca are only known in the domestic state, and are variable in size and colour, being often white, black, or piebald. The Guanaco and Vicuņa are wild and endangered, and of a nearly uniform light-brown colour, passing into white below. They certainly differ from each other, the Vicuņa being smaller, more slender in its proportions, and having a shorter head than the guanaco. It may, therefore, be considered distinct. It lives in herds on the bleak and elevated parts of the mountain range bordering the region of perpetual snow, amidst rocks and precipices, occurring in various suitable localities throughout Peru, in the southern part of Ecuador, and as far south as the middle of Bolivia. Its manners very much resemble those of the chamois of the European Alps; it is as vigilant, wild, and timid. The wool is extremely delicate and soft, and highly valued for the purposes of weaving, but the quantity which each animal produces is minimal.
The Guanaco has an extensive geographical range, from the high lands of the Andean region of Ecuador and Peru to the open plains of Patagonia, and even the wooded islands of Tierra del Fuego. It constituted the principal food of the Patagonian Indians, and they use its skin for the material out of which their long robes are constructed. It is about the size of a European red deer, and is an elegant animal with a long, slender, gracefully curved neck and slim legs.de:Lamas (Tiergattung) fr:Lama (animal) pt:llama