THE LIFE OF ANIMALS. 



VII 



In the classification of animals into species the 

 tail is often useful, and the character of the animal's 

 coat, especially if it be composed of spines or horny 

 shields, or presents other peculiarities, also serves, 

 quite often, to give a name to its wearer. The num- 

 ber, character and arrangement of the teeth, or what 

 is called the dentition, is the most useful of all in 

 making a scientific arrangement of the different ani- 

 mals into the various subdivisions. The teeth of an 

 animal are so perfectly adapted to its mode of life 

 that they especially serve to characterize it, and 

 since the imperishable nature of their tissues pre- 

 serves teeth for an indefinite time, they are particu- 

 larly useful in affording an idea of the characters, 

 habits and affinities of extinct species of animals. 



The number of species of Mammals which now 

 live and have their being on earth is about two 

 thousand, but this forms only a small minority of the 

 aggregate number of species which inhabited the 

 globe at earlier periods of its history. The study of 

 fossil Mammals has revealed the fact that many 

 animals of strange forms and characteristics for- 

 merly lived on this earth. Some were closely re- 

 lated to living species and genera, some are espe- 

 cially interesting because they furnish a connecting 

 link between existing forms of animal life and 

 structure, and some of the animals now living, like 

 the Elephants, now represent, by a few species, 

 families or orders of which many species are ex- 

 tinct. In its more extended form natural history 

 includes the study of these fossil genera, and an 

 elaborate system of classification has been created 

 in recent years, as a supplement to the investigations 

 and theories expounded by Darwin, which begins at 

 Protozoa and ascends to Man, including all the ex- 

 tinct genera of which anything is known. This, how- 

 ever, is a classification involving so much of a tech- 

 nical character and for its proper appreciation re- 

 quiring so great a degree of knowledge of compara- 

 tive anatomy, that it is obviously not adapted for 

 use in treating of zoology from a popular stand- 

 point. Therefore other systems of classification 

 are used, and that followed by Brehm in this work 

 divides the class Mammalia into fifteen main groups 

 or orders as follows: 



i. Apes and Monkeys (Pitlieci). 



2. Half-Monkeys or Lemuroids (Prosimii). 



3. Wing-handed Animals, or Bats (C)iiroptera) . 



4. Beasts of Prey (Gmrivora). 



5. Seals or Fin- footed Animals (Pinnipedia) 



6. Insect-eating Animals (Inscctivora). 



7. Rodents or Gnawing Animals (Rodcntia). 



8. Toothless Animals {Edentata). 



9. Proboscis Animals or Elephants (Proboscidea). 

 ;10. Odd-toed Animals (Perissodactyta). 



.11. Cloven-hoofed Animals (Artiodactyla) . 



12. Sea Cows {Sire/da). 



13. Whales (Cctacca). 



14. Pouched Animals (Marsupialia). 



15. Egg-laying Mammals (Monotrematd). 



This is a very convenient classification, agreeing 

 in the main with the arrangement generally in use 

 in the study of zoology, although frequently the 

 tenth and eleventh of thase orders are regarded as 

 suborders of an order named the Hoofed Animals 

 (Ungulata). 



Every scientific classification of the Mammals be- 

 gins or ends with Man, for, zoologically speaking, 

 the human being is only a Mammal: that is, a warm- 

 blooded Vertebrate, with a four chambered-heart, 

 nurtured in his infancy on mother's milk; and the 



anatomical differences which separate him from the 

 higher orders of Apes are less marked than those 

 which differentiate the latter from the South Ameri- 

 can monkeys. The first order in the classification 

 of Linnaeus was called Primates, and included Man, 

 all the Apes and Monkeys, the Lemurs and the 

 Bats. .Later zoologists by common consent ex- 

 cluded the Bats and made them a distinct order, 

 and afterward the same was done with the Lemurs, 

 but many still classify Man and all the Monkeys 

 together in' the order of Primates, dividing them into 

 five families: First, Men (Hominidm) containing as a 

 single genus Man (Homo); second, the Man-like 

 Apes (Simiidce); third, the remaining Old World 

 Monkeys (Ccrcopithicidce); fourth, the American 

 Monkeys except the Marmosets (Cebidce), and fifth, 

 the Marmosets (Hapalidce). 



The anatomical distinctions between Man and the 

 nearest Apes are, principally, the greater size of the 

 brain and brain cavity, as compared with the facial 

 portion of the skull; the smaller development of the 

 canine teeth of the male; the more complete adapta- 

 tion of the structure of the vertebral column to the 

 vertical position, Man being the only Mammal who 

 habitually walks erect; the greater length of the 

 lower as compared with the upper extremities; and 

 the greater length of the hallux, or great toe, with 

 the almost complete absence of the power of bring- 

 ing it into opposition with the other toes. 



Of course the mental difference between Man and 

 the highest of the lower animals is so great as to be 

 immeasurable, although the latter also have many 

 traits which may compare favorably with those of 

 human-kind. The devoted love of the mothers of 

 most species is a trait which they share with human- 

 ity, and in their lives and daily doings they are also 

 subject to many of the same physical conditions as 

 mankind. Like us they are born, live and die; are 

 subject to disease, to pain, to sorrow, and are capa- 

 ble of affection, sympathy and joy. Until they be- 

 come old and weary of life's struggle most species 

 of them find pleasure in association with their kind, 

 although, like Man, they have their quarrels and their 

 bickerings. 



The various orders are divided into more or less 

 numerous families, these families into genera and 

 each genus contains one or more species. Science 

 has for convenience adopted a system of double 

 names to describe each species of animals. Thus, 

 the Tiger, which belongs to the Fourth Order or 

 Beasts of Prey (Carnivord) is a member of the Cat 

 Family (Fclida) and of the genus of the Cats Proper 

 (Felis) and the species Tiger (Tigris) the scientific 

 name including both the generic and the specific 

 designations, thus: Fclis tigris. 



Dr. Brehm, in the great work to which these re- 

 marks are prefaced by way of explanatory intro- 

 duction, has excluded Man from his consideration of 

 the Natural History of Mammals. The book deals 

 with the facts that pertain to the lives of the animals 

 rather than with the anatomical details, only giving 

 so much of the latter as is necessary to a complete 

 portrait and biography. In the field of descriptive 

 zoology the work is unique, and brings the various 

 animals nearer to human comprehension and human 

 sympathy than is possible by any other method of 

 treatment; and for this reason this English transla- 

 tion of the work must be regarded as a valuable 

 acquisition to the resources of the American student 

 of zoology. 



J. W. L. 



