The Cambridge Natural History Part 41

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FIG. 240.--Carpincho. _Hydroch.o.e.rus capybara._ 1/12.

FAM. 3. CAVIIDAE.--This family, which includes the Cavies and the Capybara, is entirely South American and West Indian in distribution. It embraces animals of fair to large size, the Capybara {492} (or Carpincho) being the greatest of existing Rodents. The ears are well developed. The toes are commonly reduced, and the members of this family possess only a rudimentary tail. The hair though rough is not spiny. Other characters had best be deferred until the several genera are treated of. We shall begin with the giant of the family, the genus _Hydroch.o.e.rus_. This genus contains but a single species, _H. capybara_ of South America. It reaches a length of some 4 or 5 feet. The ears are not large; the tail is completely absent. The fore-feet are four-toed, the hind-feet three-toed; the digits are webbed, though not to a very great degree, and the nails have the appearance of hoofs. There are fourteen dorsal vertebrae; the clavicle is absent. In the skull the paroccipital processes are of great length. The infra-orbital foramen is large. The most remarkable fact about the teeth is the great size of the posterior molar of the upper jaw; it has fourteen folds of enamel, more than all the anterior teeth possess collectively. The incisors are white and grooved in front. The measurements of the alimentary tract as given by Tullberg are: small intestine, 4350 mm.; caec.u.m, 450 mm.; large intestine, 1500 mm.

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FIG. 241.--Patagonian Cavy. _Dolichotis patachonica._ 1/10.

The Capybara or Carpincho is largely aquatic in its habits. Their "favourite locality," writes Mr. Aplin,[361] "is a broad laguna {493} in the river, furnished with open water, and also beds of 'camelotes,'--a sloping open gra.s.sy bank on one side, where the Carpinchos can lie in the daytime in the cooler weather, sleeping and basking in the sunshine; on the other a low shelving bank, clothed with 'Sarandi' scrub growing out into the black reeking mud and shallow water beyond." They always take to the water when alarmed, at a rate and with a gait which reminded Mr. Aplin of a Pig. When in the water they swim slowly with the upper part of the head, including nose, eyes, and ears, above the surface. But they can dive for a considerable time and distance, and baffle their enemies by seeking the shelter of a ma.s.s of water-plants, and lying there with their noses only just above the surface.

The genus _Dolichotis_[362] has long ears, and generally resembles a rather long-legged Hare in appearance. The front-feet are four-toed, the hind three-toed. The Patagonian Cavy, as this animal is called, has twelve dorsal vertebrae, and rudimentary clavicles.[363] The paroccipital processes are long; the incisors are white, and are not grooved in front.

The sternum has six pieces, and seven ribs reach it.

_Cavia_, including the species _C. porcellus_, the Guinea-pig (which name is a corruption apparently of Guiana pig), has the same number of toes on its hind- and fore-feet as has the Capybara. The name applied to the wild stock whence our Guinea-pig is derived is the Restless Cavy. The fur is greyish; of the domestic animals the colour is too well known to need description.

FAM. 4. DASYPROCTIDAE.--The genus _Coelogenys_ includes but two species.

_C. paca_, known as the "Spotted Cavy" or "Paca," has a brown body, with white spots like those of a Dasyure; it is one of the largest of Rodents, and has a quite short tail. The hand and foot are both provided with five digits; but the thumb is small, and in the foot the three middle toes considerably exceed the others in length. The hind-foot is practically three-toed. The fibula is not nearly so reduced as in _Dolichotis_. The skull of the animal is remarkable for the extraordinary development in breadth of the jugal arch, which is sculptured externally. There is a large cavity formed below, at the maxillary end of this huge {494} arch, by the curving inwards of the bone, which lodges a cavity continuous with the mouth. The palate has anteriorly a ridge on either side, and is thus divided from the sides of the face in a way which is not found[364] in the allies of _Coelogenys_. Clavicles are present. There are thirteen dorsal vertebrae. The incisors are coloured red in front. The animal is South American, and in that continent is limited to the Brazilian sub-region.

This, the best-known species of Paca, is called the Gualilla by the natives of Ecuador; in the same district another form is met with which the natives term Sachacui (signifying Forest Cavy). It is very often the case that a different native name expresses a real specific difference; and to the latter form M. T. Stolzmann has given the name of _C. taczanowskii_.[365]

This form, unlike the common Paca, which is fond of forests and low-lying ground in the neighbourhood of water, is alpine in habitat, living upon mountains of 6000 to 10,000 feet. It burrows in much the same way as its congener, and is greatly sought after as food, its meat possessing an "exquisite taste." It is pursued by dogs, by whose aid one of the two entrances to the burrow is guarded, and the creature is smoked out and killed with a stick.

The genus _Dasyprocta_, containing those Rodents known as Agoutis, is divisible into several species, apparently about twelve, all of which are, like the Pacas, confined to the Neotropical region. They have, however, a much wider range within that region, and occur as far north as in Central America and in some of the West Indian Islands. They are of rather smaller size than the Paca, and are without spots. The colour is of a golden brown in some forms, but usually has a freckled, grizzled, greenish kind of appearance. The tail is stumpy, the hind-limbs are distinctly longer than those of the Paca, and the two lateral toes have disappeared from the feet--a concomitant as it seems of the Agouti's greater powers of running.

The three metatarsals are closely pressed together, and the foot is as it were on the way towards the highly-modified foot of the Jerboa. The fore-feet are, however, five-toed. The clavicle is rudimentary,[366]

whereas it is well developed in the Paca. The skull has not the peculiar modifications of that of the last-mentioned type. The sternum has seven {495} pieces, and eight ribs reach it. A curious difference between this genus and the last is in the relative proportions of the regions of the intestine. The figures given by Tullberg for the two animals are--for _Coelogenys_, small intestine, 4800 mm.; caec.u.m, 230 mm.; large intestine, 21,000 mm.;--for _Dasyprocta aguti_ the same author gives: small intestine, 4200 mm.; caec.u.m, 200 mm.; large intestine, 1000 mm. The Agouti, says Mr.

Rodway,[367] is as wily as the Fox. "If chased he will run along the shallows of a creek to hide his scent from the dogs, or swim over and back again several times for the same purpose. He never runs straight when pursued, but doubles, often hiding until a dog has pa.s.sed, and then making off in a different direction. Like the fox he has been hunted for a very long period, and, like Reynard, has grown wiser with every generation."

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FIG. 242.--Agouti. _Dasyprocta aguti._ 1/10.

FAM. 5. DINOMYIDAE.--The genus _Dinomys_ of Dr. Peters[368] is a very little known and remarkable form from South America allied to the Capybara, the Chinchilla, and other South American Rodents. It is only known by a single example found wandering about a courtyard in a town of Peru. It is externally like, and of about the same size as the Paca, but has a hairy tail. The animal is four-toed and plantigrade; the ears are short, and the nostrils are [369]-shaped. It is usually regarded as belonging {496} to a separate family which will include but the one species, _D. branickii_.

FAM. 6. CHINCHILLIDAE.--This family, likewise South American, contains three genera,[370] all of which agree in having long limbs, especially the hind-limbs, and a bushy and well-developed tail. The hair is exceedingly soft, hence the commercial value of "chinchilla."

The genus _Chinchilla_, containing but a single species, _C. laniger_, is a small and squirrel-like creature, living at considerable heights in the Andes. The eyes, as it is a nocturnal creature, are naturally large; and so also are the ears. The fore-feet have five toes, the hind-feet only four; they are furnished with feeble nails. The innermost toe of the hind-foot has a flat and nail-like claw. There are thirteen dorsal vertebrae, and the long tail has more than twenty. The clavicle is well developed, as in the other genera of this family. The large intestine of this animal is extraordinarily long; the proportions of the different regions of the gut are shown by the following measurements: small intestine, 820 mm.; caec.u.m, 125 mm.; large intestine, 1340 mm. Such a disproportion between the large intestine and the small, to the advantage of the former, is a very strange fact in the anatomy of this Rodent.

The genus _Lagidium_ (also called _Lagotis_), which includes "Cuvier's Chinchilla," is also a mountain dweller. There are several species of this genus, which differs from _Chinchilla_ by the complete abortion of the thumb and of the great toe. The intestinal proportions are those of _Chinchilla_. The ears and tail are long. _L. cuvieri_ measures 1 feet in length.

_Lagostomus_, again, has but one species, _L. trichodactylus_. The animal has a tail about half the length of the body. The digits are reduced as compared with _Chinchilla_, there being but four on the fore- and three on the hind-feet. There are only twelve dorsal vertebrae, and seven ribs reach the sternum. In the skull a distinguishing mark from the last two genera is the separation of the infra-orbital foramen into two by a thin lamella of bone. The large intestine is between one-half and one-third the length of the small intestine, and thus differs much from that of _Chinchilla_. {497}

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FIG. 243.--Vizcacha. _Lagostomus trichodactylus._ 1/10.

The Vizcacha lives in societies of twenty to thirty members,[371] in a "village" ("Vizcachera"), a dozen or so of burrows, which intercommunicate.

They lie at home during the day and come out in the evening. Their burrows, like those of the Prairie Marmot, harbour other creatures, which apparently live on amicable terms with the Vizcachas; such are the burrowing owl, a small swallow, and a _Geositta_. The Fox also affects these burrows, but then he ejects the rightful owner of the particular burrow which he selects. When the young Foxes are born the vixen hunts the Vizcachas for food. The Vizcacha has a most varied voice, producing "guttural, sighing, shrill, and deep tones," and Mr. Hudson doubts if there is "any other four-footed beast so loquacious or with a dialect so extensive." These animals are very friendly, and pay visits from village to village; they will attempt to rescue their friends if attacked by a Weasel or a Peccary, and to disinter those covered up in their burrows by man.

FAM. 7. CERCOLABIDAE.--A number of the characters which differentiate this family from the Hystricidae or Ground Porcupines of the Old World are given under the description of the latter. The princ.i.p.al external characters are the prehensile tail, the admixture of spines with hairs, and the nature of the sole of the foot. In these points the New-World Cercolabidae differ from the Old-World Hystricidae. It is interesting to notice that {498} in both families we have long-tailed and short-tailed forms. _Cercolabes_ corresponds to _Atherura_ or _Trichys_, and _Erethizon_ to _Hystrix_.

The genus _Erethizon_, the "Urson" of Canada, has a short, stumpy tail. Its spines are almost hidden by enveloping hair. The fore-feet have four, the hind-feet five toes. The short tail of this creature is remarkable when we reflect upon its climbing habits. It appears, however, to be a weapon with which it strikes sideways at the enemy.

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FIG. 244.--Brazilian Tree Porcupine. _Sphingurus prehensilis._ 1/6.

Of the Neotropical genus _Cercolabes_ (sometimes called _Sphingurus_, _Synetheres_, or _Coendou_) there are some eight or nine species, all found in Central and South America. The animal is arboreal, and has in correspondence with that habit a prehensile tail. The spines are not so stout as in the Ground Porcupines, and are often coloured yellowish or reddish. In correlation with its tree-frequenting habits the bones of _Cercolabes_ show certain differences from those of the Ground Porcupines.

The scapula is broader and rounder in front than is that of _Hystrix_; the phalanges of the thumb (which is rudimentary) are fused together as in the Canadian _Erethizon_; but those of the very small hallux are also fused, whereas in _Erethizon_, as in _Hystrix_, they are separate. In one species, _C. insidiosus_, Sir W. Flower states that there are as many as seventeen dorsal vertebrae and thirty-six caudals. The tail is thus very long. In _C.

villosus_ there are fifteen dorsals and twenty-seven caudals; eight ribs reach the sternum, which is composed of seven pieces, the {499} sixth being very small. The clavicles are well developed. A curious fact about _C.

villosus_ is that the acetabular cavity is perforate (on both sides), or at least only closed by membrane. In many forms of Rodents the bone is very thin in this region. This fact perhaps lessens the significance of the perforation of the acetabulum of _Echidna_ (see p. 109).

Of the allied genus _Chaetomys_, also Neotropical, there is but a single species, which inhabits Brazil. It has a nearly completely closed orbit, a feature which differentiates it from the last animal, and one which also shows it to be a more modified form. The spiny covering is less p.r.o.nounced than in its allies.

FAM. 8. HYSTRICIDAE.--This family is characterised by the fact that all its members possess spines; but the tail, if at all long, is not prehensile, and the soles of the feet are smooth and not covered with rough tubercles, as in the Tree Porcupines of the next family, Erethizontidae. The clavicle is less developed than in the arboreal forms. In the organs of digestion there are points of a family difference between the two groups of spiny Rodents. The tongue has serrated scales arranged in transverse rows, which are directed backwards. A gall-bladder, though not always present, is sometimes found; it apparently never exists in the arboreal Porcupines and in _Erethizon_. The lungs show a great tendency to subdivision, which appears to be especially marked in the genus _Atherura_. The caec.u.m seems also to be shorter in the Ground Porcupines. In _Hystrix cristata_ the small intestine measures 15 feet 7 inches; the caec.u.m, 8 inches; the large intestine, 4 feet 4 inches:--in _Atherura africana_ the caec.u.m measures 7 inches; the large intestine, 1 foot 10 inches. The corresponding measurements of _Synetheres villosus_ were: small intestine, 7 feet 3 inches; caec.u.m, 1 foot 4 inches; large intestine, 2 feet 7 inches. In _Erethizon_ the caec.u.m is 2 feet 4 inches in length. These differences are too large and too constant in a number of presumedly allied forms to be overlooked.

Mr. Parsons has directed attention[372] also to a number of muscular differences, such indeed as might be expected to occur between animals of such different habits.

The genus _Hystrix_ embraces the better-known Porcupines. It is a genus of wide range, extending from the East Indies to Africa, {500} and even occurring in Europe. There are several species, of which the common _Hystrix cristata_ is the best known, and is the one which is to be found in Europe.

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FIG. 245.--Common Porcupine. _Hystrix cristata._ 1/10.

The spines of the common form and of the others are solid in the middle of the body, but on the tail they are expanded into hollow quills, which make much rattling. They are as a rule black and white, the middle of the spine being banded with black. A great crest of coa.r.s.e long hairs on the head is responsible for the scientific name of the well-known form. Sometimes in this genus, as in the Tree Porcupines of Brazil, the spines are orange or yellow; but it is said that the colour is soon lost in this country. As a matter of fact it is the easiest thing in the world to wash out with ordinary tap-water much of the yellow colour of the spines of the South American _Sphingurus_. The same may be the case with the pigment of the Old-World Porcupines. There are fourteen to fifteen dorsal vertebrae and four or five lumbars. The tail varies in length, but is shorter than the long tail of the arboreal New-World forms. It seems impossible when mentioning the Porcupine to escape from some observations about its alleged habit of shooting its quills. For some reason or other Buffon has got the credit of inventing, or at {501} least promulgating, this legend, which has even grown so in the telling that the quills are said to be capable of penetrating planks of wood. What Buffon said _apropos_ of this matter is, "The marvellous commonly is pleasingly believed, and increases in proportion to the number of hands it pa.s.ses through." It is of course the rattling of the spines and the occasional falling out of loose ones which has started the legend. They are, however, excellent weapons of offence, and the animal charges somewhat backwards to make the best use of them against the foe. The spines, however, are by no means an absolute protection, since, as Mr. Ridley informs us,[373] Tigers will kill and eat these animals just as the Thylacine is apparently indifferent to the spiny armature of _Echidna_.

Of the Brush-tail Porcupine, _Atherura_[374] there are at any rate two species, the West African _A. africana_ and the Malayan _A. fasciculata_.

It is interesting that the gap in the present distribution is partially filled by the discovery of fossil teeth near Madras. The genus does not differ widely in external appearance from _Hystrix_; it has, however, a rather longer tail; there are fewer large spines, and there is a tuft of them at the end of the tail, whence is derived the name of the genus. The frontal bones project a little distance between the nasals, a feature which does not seem to appear in the true Porcupines. There are fourteen dorsal vertebrae and five lumbars. The twenty-four caudal vertebrae of this Porcupine shows how much longer is its tail than that of _Hystrix_; for in the latter twelve is about the number.

A third genus of Old-World Porcupine is the singular _Trichys_.[375] Of this there is but one species, _T. lipura_. It is a curious fact that out of three examples, all from Borneo, two were quite without a tail. But this appears to be merely a mutilation, though it is singular that the natives state it to be without a tail. One cannot help thinking of the way in which lizards sometimes shed their tails when pecked at. The tail of this genus is more than half the length of the body and head. _Trichys_ has sixteen dorsal and six lumbar vertebrae. There is a tuft of quills at the end of the tail, which are thin and compressed, {502} though truncate at the free extremity and hollow; they represent in a more rudimentary way the much stronger tuft at the end of the tail of other Porcupines. It is a curious fact that this and other Porcupines possess a mechanism for warning their foes precisely comparable to that of the rattlesnake. There are sixteen dorsal vertebrae.

SUB-ORDER 2. DUPLICIDENTATA.

The chief feature of this group is the existence of two pairs of incisor teeth in the upper jaw, of which the inner are very small and lie behind the outer. In the skull the infra-orbital foramen is small; the incisive foramina are very large. The tail is short or absent.

FAM. 1. LEPORIDAE.--This family is distinguished from the Lagomyidae by the long ears, by the tail, which is present, though short, and by the longer limbs. There are six teeth belonging to the molar series in the upper jaw, and five of the same in the lower. The clavicle is imperfect.

The longest known genus of this family, _Lepus_, was, until the quite recent discovery of _Romerolagus_, the only genus. It is of universal range, excepting Australasia and Madagascar, and consists of about sixty species. These are the Hares and Rabbits, to the former being a.s.signed the longer-limbed forms.

As every text-book of zoology contains a more or less elaborate account of the structure of the Common Rabbit, and as there is but little structural difference between the members of the genus, a short account of the generic peculiarities of _Lepus_ will suffice here. The fore-feet are five-toed, the hind-limbs four-toed. The hairy integument enters the mouth cavity, and the inside of the cheeks have a hairy covering. The soles of the feet are, moreover, hairy. The maxillary bones are curiously sculptured.

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FIG. 246.--_Lepus cuniculus._ Skull. A, Lateral view; B, ventral view.

_ang.pro_, Angular process of mandible; _as_, alisphenoid (external pterygoid process); _aud.me_, external auditory meatus; _b.oc_, basioccipital; _b.sph_, basisphenoid; _cond_, condyle; _cor_, coronoid process; _fr_, frontal; _int.pa_, inter-parietal; _ju_, jugal; _lcr_, lachrymal; _max_, maxilla; _nas_, nasal; _opt.fo_, optic foramen; _o.sph_, orbitosphenoid; _pa_, parietal; _pal_, palatine; _pal.max_, palatine plate of maxilla; _pal.p.max_, palatine process of premaxilla; _par.oc_, paroccipital process; _peri_, periotic; _p.max_, premaxilla; _pt_, pterygoid; _p.t.sq_, post-tympanic process of squamosal; _s.oc_, supraoccipital; _sq_, squamosal; _ty.bul_, tympanic bulla; _vo_, vomer; _zyg.max_, zygomatic process of maxilla. (From Parker and Haswell's _Zoology_.)

The Common Rabbit, _L. cuniculus_, differs from the Common Hare in the comparatively shorter ears and legs. The ears have not, to so marked a degree, the black tips of those of the Hare. The animal, moreover, produces naked young, and lives in burrows of its own excavation. A difference in the structure of the caec.u.m, which distinguishes the Rabbit from the Hare, has been {504} pointed out by Professor W. N. Parker.[376] These differences have led some to approve of its separation from the Hares into a genus _Oryctolagus_. This animal is believed to be an introduced species, and to have been brought by man into these islands. Its original home is the Spanish Peninsula, the south of France, Algiers, and some of the Mediterranean islands. Mr. Lydekker thinks that the only other species of _Lepus_ which can be considered to be a "Rabbit" is the Asiatic _L.

hispidus_.

Of Hares there are two species in this country. The Common Hare, _L.

europaeus_ (the name _L. timidus_ seems to be really applicable to another species to be referred to presently), extends all over Europe excepting the extreme north of Russia and Scandinavia. It is not known in Ireland, and, curiously enough, attempts to acclimatise this animal in that island have failed--a state of affairs which contrasts with the fatal ease with which the Rabbit has been introduced into Australia. Ireland has, however, the Variable Hare, _L. timidus_ (also called _L. variabilis_), a species which is common in other parts of Europe, and which extends as far east as j.a.pan.