Book II. DISTRIBUTION OF ANIMALS. WT 



parts which they have thus fortified. Having thus made choice of situations where they are protected 

 from sudden alterations of temperature, and having assumed a position similar to that of their ordinary 

 repose, these hybernating animals fall into a state of insensibility to external objects. In this torpid 

 state they suft'er a diminution of temperature ; their respiration and circulation Ijecome languid ; their 

 irritability decreases in energy ; and they suffer a loss of weight. 



1976. The abundance or scarcity of food has a powerful influence on the geographical 

 distribution of animals. Many species of insects are restricted in their eating to one 

 kind of plants, or are parasitical on one species of animal. The distribution of such 

 animals is thus dependent on their food. The same remark is generally applicable to 

 carnivorous and phytivorous animals. But, in many species, though the restriction is 

 absolute as to the nature of the food, it admits of a considerable range with regard to 

 the variety or kind. Thus, though the lion is restricted to flesh, his cravings are equally 

 satisfied with the carcase of a horse, a cow, or even of man. The hog in general feeds 

 on roots, but it is not confined to those of one kind of plant ; hence it can subsist where- 

 ever the earth is clothed with verdure. 



1 ^77. The seaso?is exercise a powerful influence on animals^ directly, in reference to their 

 temperature, and, indirectly, with regard to the production of their food. Thus, the 

 insect that feeds on the leaves of a particular tree, can only enjoy its repast during that 

 part of the season when this tree is in leaf. How, then, is life preserved during the 

 remaining portion of the year ? The resources are numerous. It either exists in the 

 form of an unhatched egg, an inactive pupa, in the imago state, requiring little food, or 

 actually becoming torpid. 



1978. The birds which feed on insects in summer, in this climate, are, from the absence of this kind of 

 sustenance in winter, obliged to have recourse to various kinds of vegetable food during that season. 

 Should this change of diet be unsuitable, migration to other districts, where a proper supply can be 

 obtained, becomes indispensably requisite. In compliance with these regulations, we observe numerous 

 mammalia, birds, and fishes, accompany the shoals of herrings in their journeys ; and the grampus and 

 seal enter the mouths of rivers in pursuit of the salmon. The bats, which feed on insects in summer, 

 could not in this country obtain a suitable supply of food. Yet the race is preserved, since the fall of 

 temperature, which is destructive to insect life, brings on the winter torpor. With many quadrupeds, 

 however, and even insects, especially the bee, where migration to more fertile districts is impracticable, 

 and where torpidity is not congenial to the constitution, there is an instinctive disposition to be provident 

 of futurity. Of quadrupeds which possess this disposition, the beaver and the squirrel may be considered 

 as among the most remarkable. 



1979. The influence of situation on the distribution of animals, is considerable. Some 

 animals reside wholly in water ; others are amphibious. Among terrestrial animals, 

 there are many which execute all the operations of life in one particular situation, in- 

 fluenced, however by its various conditions. Such animals are necessarily limited to 

 those countries where such situations occur. There are others, however, which shift their 

 situations at particular seasons, without reference either to temperature or food. The 

 curlew, which can at all times procure a subsistence on the sea-shore, and resist or 

 counteract the changes of the seasons, retires during the period of breeding, to the 

 inland marshes. The heron, which is equally successful in procuring food on the shore, 

 is destined to build its nest on trees, and consequently must betake itself to wooded 

 districts for the purposes of incubation. Its haunts in Britain are termed heronries or 

 heronshaws. Many terrestrial animals, especially of the insect kind, pass the first period 

 of their existence in "the water. The old animals in consequence seek after that element 

 in which to deposit their eggs, however independent they may be of its presence for their 

 ordinary personal wants. 



1980. The rapacity of some animals considerably affects the distribution and extension 

 of others. Of all the foes of the animal tribe none is so powerful as man. Against 

 many species, hostile to his interests, he carries on a war of extermination. Others he 

 pursues for pleasure, or for the necessaries or luxuries of life which they yield. In 

 these conquests, the superiority of his mental powers is conspicuously displayed, and his 

 claim to dominion established. Unable to contend with many species in physical 

 strength, he has devised the pit-fall and the snare, the lance, the arrow, and fire arms. 

 Aided by these, every animal on the globe must yield to his attempts to capture. The 

 lion, the elephant, and the whale, fall the victims of his skill, as well as the mouse or the 

 sparrow. Since the use of gunpowder, indeed, the contest is so unequal, that it is in 

 the power of man to control the limits of almost every species whose stations are ac- 

 cessible. The havoc which man thus commits in the animal kingdom has occasioned 

 the extirpation of many species from those countries of which they were formerly the 

 natural possessors. In this island, since the Roman invasion, some species of quadrupeds 

 and birds have disappeared ; and others are becoming every year less numerous. Of 

 those which have been extirpated, the bear and the beaver, the crane and the capercailzie, 

 may be quoted as well known examples. The same changes are taking place in every 

 cultivated region of the earth, each having within the very limited period of history or 

 tradition, lost many of the original inhabitants. 



1981. An acquaintance with the laws which regulate the geographical distribution of animals is indis- 

 pensably necessary in our attempts to naturalise exotic species. The temperature most suited to their 

 health, the food most congenial to their taste, and best fitted to their digestive organs, the situation 

 to which their locomotive powers are best adapted, and the foes against which it is most necessary te 



