80 
FIRST CLASS OF THE VERTEBRATED ANIMALS. 
that daily sleep of Jlan and the lower animals during the hottest parts of the day, and 
called the sieste in Spain and Italy. 
Neither cold nor heat can thus be said to be the cause of hvbernation and testi- 
vation, although they are auxiliaries to those states. In the same manner as it is 
neither cold nor heat that compels us to sleep every night, but a constitutional fatigue, 
and the necessity of rep^ring our forces ; so in these annual sleeps the absence and 
presence of heat arc merely proximate causes. Nature has wisely constituted 
these animals thus ; for it U probable that their feeble constitutions would have 
otherwise failed to resist the cold, or they would perhaps have been unable to procure 
an adequate supply of food. \^*hen the period of torpidity is over, the rutting season 
usually commences, and these animals then enter anew upon the functions of life with 
renovated faculties. 
GENERAL REVIEW OF THE MAMMALIA CONTINUED. 
PJtenome7ia of Reproduction — Growth— Duration of Life. 
ScARCEi.Y have the Mammalia attained the full period of their growth, when another 
order of functions malce their appearance. Their animal forces then acquire a new 
direction, and Life, which was fonnerly confined to the development of the individual, 
now applies itself towards the continuation of the species. 
The time when the phenomena of reproduction first exhibit themselves is termed 
Puberty. Then the reproductive organs, which previously were but slightly apparent, 
acquire a remarkable development, and in some species obtain certain external cha- 
racters which remain during the whole course of their lives. Infancy is the period 
comprised between birth and puberty. It is during the time preceding puberty that 
the growth of the body chiefly takes place, although it may continue for some lime 
afterwards. The length of the period of infancy bears to that of life a certain relation, 
which may be regarded as almost constant. BufTon remarks, that in our climates, 
for the largest animals, it is about the one-seventh part of their entire life. 
At the age of puberty, the Mammalia assume the characters of maturity. Their 
height attains its greatest limit, and the distinctive marks of each animal become 
bold and well-defined. The physiognomy assumes a more animated expression ; their 
voice becomes hoarser or stronger, and the fur handsomer ; while the vivacity of their 
movements marks the impetuosity of those passions which animate them at this epoch. 
The male becomes distinguished from the female by colours which arc commonly 
darker or browner, and in many species by certain definite external characters. 
Thus, some male Apes acquire a beard and a coat of long hair ; the Lion obtains a 
inane ; and the Stags and Roebucks arc armed with branching horns, of which the 
females are nearly always deprived. The Ile-Goats and Rams are at once distin- 
guished from the females by their horns, their masculine gait, and combative dispo- 
iJition. This superiority in the males is most marked among the Ruminantia, whicli 
are commonly polygamous, and where each male having several of the other sex to 
keep in subjection, it becomes necessary to assign him a physical superiority, 
unnecessary in the monogamous species, where the sexes are always more equal in 
strength. 
Puberty constantly exhibits itself much sooner in females than in males, although 
the reproductive power remains longer with the latter than with the former. In our 
climates Man attains this condition at the age of fifteen or sixteen, and Woman 
at that of fourteen or fifteen; in warmer climates it exhibits itself at the age of 
twelve to fourteen in the former, and at ten to twelve in the latter. With most of 
the other Mammalia, excepting the domestic animals, we are still ignorant of the pre- 
cise periods when puberty commences. Dogs arc capable of rejiroducing at the age 
of nine or fen months ; Cats from a year to eighteen months. A Lioness of the “ Me- 
nagerie ” at Paris was six years old when she exhibited these phenomena for the 
first time. Rabbits can procreate at the age of five or six montlis ; Hares a little 
later; and Guinea-Pigs at five or six weeks. Sheep sliow signs of puberty when 
one year old; Rams, lie- Goats, and Stags, at eighteen montlis. Horses produce 
at two ycats and a half, and Mares a little sooner. Camels, according to the ancients, 
at three years ; Wolves at two years ; Cows at eighteen months; Bulls six months 
later ; the She-.\s3 from eighteen to twenty months ; and the Ass at two years, it 
is, however, the interest of the Grazier to prevent the domestic animals from pro- 
creating before they have attained their lull growth, otherwise the deterioration of 
the races is sure to follow. 
There are certain seasons of the year when most Mammalia become susceptible of 
the instincts of reproduction. This is termed the ruttiny season, during which the 
usual character of the animals is totally changed, especially of the males. The most 
timid animals, being excited by the abundance of food and the internal suggestions of 
instinct, acquire a degree of courage and even fury, which urges them on in a career 
of madness, which can be compared only to the habitual ferocity of the most formi- 
dable species. The females also, at this period, lay aside their habitual reserve, and 
are seen to provoke the males by biting, teasing, and following them everywhere. 
Some Mammalia in our countries, as well as in those of the south, whether males 
or females, remain always in a state adapted for procreation, after having once 
attained the age of Puberty, With the exception of the Monkeys, this happens 
only to those species, which either receive an abundant nourishment from Man, 
or else obtain a plentiful supply by plundering his stores. Of the first kind arc 
the Dog, Cat, Rabbit, Guinea-Pig, Hog, Bull, Buffalo, Horse, and Ass; in the 
second division must be placed the common Rat, the common IVIouse, the "Wood 
IMousio, the Economic Mouse, and the Hamster. With the animals of the Me- 
nagerie, the change of climate which they experience, and tlie constraints of con- 
finement, occasion them to undergo certain deviations from their natural period of 
rutting. Among these may pai'ticularly be enumerated, the Lion and other Cats 
from warm climates, the Cape Ichneumon {Mangusta ynsea)^ and the Cape Genet 
( Paradoxurus typusf the Ichneumon of Egypt, the Gnu Antelope, and the Zebra; 
also the Axia Dew from the banks of the Ganges, and the Kangaroo of New 
Holland. 
It commonly happens, however, with the Mammalia, when they have not been 
modified by domestication or confinement, that each has a peculiar season when the 
phenomena of the rut more especially present themselves. Thus, winter is the rut- 
ting time of the Wild Cat and Martens of Europe ; of the Wolf, from Dccembfr to 
February; of the Jackal and Corsac Fox (Canis Corsac)f only in winter. The 
Arctic Fox (CuniV lagnpus) is in season at the end of February; the Bear, in sum- 
mer; the Hedgehog, at the end of winter; and the Hare in February or March. 
The Beavers seek the females in the beginning of January ; the American Ondatra 
and the Common Squirrel, in spring. The Dromedaries seem to be more in season 
Rbout the month of January than at any other time. Camels begin about the middle 
of November, and end at the coraraeneement of February. The month of Septem- 
ber is the chief time for the Sheep and Goats, although the males of both species are 
Always fit for procreation. In the Stags of our countries, the Roebuck, and other 
Deer, the rutting season succeeds to the period when the honis are renewed, that is 
in November, and after this time the horns fall. The Rein-Deer are in the same case. 
Thus the season of the rut varies with the species; but it is always so arranged 
in reference to the terra of gestation, that the young may make their appearance at 
a favorable sea.H 0 ii of the year, when the heat of summor will serve to aid their 
growth, and assist in developing their forces. At tliis season, also, a luxurious 
vegetation supplies the herbivorous animals with abundance of food, which favors 
the secretion of milk, and ensures its continued supply. 
The external signs of the rutting period vary greatly with the several species. In 
those which are capable of procreating at all seasons, such as Man, the Monkevs, 
Dogs, Cats, and Horses, no particular sign is observed. It is different with the 
Rodentia. Daus la plup.irt dcs Rongeurs (Rodentia), les tcsticules, ordinairement 
petits ot comme caches dans I’abdomen, prennent un volume tres considerable et 
deviennent fort apparens. C*cst eu particulitT, ce qu’ou remarque dans les Rats, 
les Surmulots etc. oh ccs parties font, h cette epoque, une saillie tres-remarquablc a 
la base Uc la queue, ct doimentau corps une figttrepointuoverscetteextremite.” At 
this period (be Elephants secrete, on the side of the bead behind the ears, a brownish 
fluid, which proceeds from glands situate under the skin. The Bactrian Camel diffuses 
a most disagreeable odour at this season. At first he undergoes a violent perspir.ition, 
which lasts for fifteen days; then a blackish and viscous fluid exudes from the neck, 
not through any particular opening, hut merely from the pores of the skin, so that 
the Persians arc obliged to cut his hair very close. In the Dromedar)*, also, the 
male presents at this particular season a similar phenomenon. We find, likewise, that 
all those odoriferous Mammalia, which are supplied with pouches from whence the 
odours emanate, emit their pcrfamt‘s at this time with unusual force. In the greater 
number of animals belonging to the Deer Genus, and in several Antelopes, tlm 
larynx or windpipe of thi; male projects considerably ; and it cannot be doubted 
that the change of tone which his voice undergoes is owing to this cause. 
It usually happens that the females exhibit the external signs of the rutting season 
in a milder and more subdued form than the males. “ Alors seulemcnt, observes 
M. Desinarcst, “ les organes externcs de la generation se tumefient legeremcnt, 
s’entr’ouvrent, et sent continuelleraent humectes par un fluido plus ou inoins vis- 
queux, qui, chez les juroens, oii il est particulierement abmidaut a re 9 U le nom dTiip- 
pomancb. Neaumoins, la tumefaction et la rongeur excessive des fesse? de certaincs 
femclles de singes doivent etre considcrecs comme un signe du rut, ct sans nul doute 
aussi, les ecoulcmcns sauguins qui ont lieu a ties epoques regulibres et plus ou moins 
rapprochecs, mais fixes chez cellos de quelqaes espbees.” Those appearances mav 
present themselves in the females at intervals more or less considerable in the course 
of the year. 
Among the Mammalia, and indeed in all living beings, the period of puberty and 
reproduction is one of energy and strength ; all their affections become more ardent, 
and their wants irresistible. The term rut, from mere, to rush headlong, serves to 
express the furj’ which transports these lower animals. 
In furias ignesque ruunt, amor omnibus idem. 
Alike ferocious and untameable, they are susceptible at this period neither of fear 
nor any other passion, and seem deaf even to the calls of hunger or sleep. Tiie Bull 
forsakes the meadows, and rambles everywhere in search of his mate. The forests 
resound with the howling of contesting Wolves, and the Lion, with a deafening roar, 
defies his rivals to the combat. We may e.isily perceive the final cause of these 
contests among the lower animals during the rutting season. Nature ever sacrifices 
the interests of individuals towards the perfection of species. The most vigor- 
ous males always possess thi most formidable weapons of attack and defence, while 
the more effeminate individuals exiubit their feeblenoss at once in their horns and their 
want of courage. It is especially among the polygamous races where these combats 
of the rutting season are more conspicuously observable, because each male fights for 
several females. In the monogamous species, on the contrary, where the numbers 
of the sexes axo nearly equal, these battles seldom occur. Again, in the Carnivora, 
when the number of the males surpasses that of the females, duels become both fre- 
quent and sanguinary. The Seals (^Phoca) are perhaps more polygamous than any 
other of the JMammalia. Each maintains a kind of seraglio or family, composud» 
perhaps, of one hundred and twenty females, which he defends from the approach of 
any other male, with the utmost jealousy and rage. Oilier species, less faithful or 
more complaisant, pass from conquest to conquest, and pay their court to all ih® 
. beauties of the neighbourhood. 
The duration of this season varies with different species; but, in general, among 
the wild animals it ceases as soon as the females have been fecundated. Witii 
most of the latter, the external signs of the rut immediately disappear; the females 
resume their usual reserve, and repel with rudeness the approaches of the male* 
There are exceptions, in the Monkey?, the IMare, and in our own species. The fciual® 
Rabbit is likewise an exception, though only an apparent one ; as from the peculiar 
formation of the matrix, she is susceptible of a twofold impregnation, or superfc' 
tatlon. 
“ Le mode d’accouplement varie peu dans les Mammiferes ; en general cet acte ft 
lieu comme dans nos espcces domestiques d’Europe. Oo avait Uit, que ceux de oes 
