12 



INSTINCT. 



they may be seen in great numbers alighting on 

 walls, rails, path-ways, &c."* Some insects, 

 and many larvae (as the silk-worm) approaching 

 to the 'state of pupse, form a covering for them- 

 selves by exudations from their own bodies, 

 likewise at some distance of time before the 

 frosts set in. Many hybernating animals ex- 

 hibit so little of any vital action as to require 

 little or no nourishment during the winter, ex- 

 cepting the product of absorption of their own 

 fat; but it is also well known that many of 

 different orders (as the beaver, the hedgehog, 

 the squirrel, the dormouse, the bee, which are 

 seldom or never quite torpid,) are guided by 

 instinct to lay up stores of provisions, on which 

 they subsist during the winter. Some of these, 

 as the lemming, have been observed to spread 

 out their stores to dry in fine weather. Some 

 of the most curious of the provisions of this 

 kind are the following : 



" There is an animal, the rat-hare, which is 

 gifted by its Creator with a very singular in- 

 stinct, on account of which it ought rather to be 

 called the hay-maker, since man may or might 

 have learned that part of the business of the 

 agriculturist, which consists in providing a store 

 of winter provender for his cattle, from this 

 industrious animal. Professor Pallas was the 

 first who described the quadruped exercising 

 this remarkable function, and gave an account 

 of it. The Tungusians, who inhabit the country 

 beyond the lake of Baikal, call it Pika, which 

 has been adopted as its trivial name. 



" About the middle of the month of August 

 these little animals collect their winter's pro- 

 vender, formed of select herbs, which they bring 

 near their habitations and spread out to dry 

 like hay. In September they form heaps or 

 stacks of the fodder they have collected under 

 places sheltered from rain or snow. Where 

 many of them have laboured together, their stacks 

 are sometimes as high as a man, and more than 

 eight feet in diameter. A subterranean gallery 

 leads from the burrow below the mass of hay, 

 so that neither frost nor snow can intercept their 

 communication with it. Pallas had the pa- 

 tience to examine their provision of hay piece by 

 piece, and found it to consist chiefly of the 

 choicest grasses and the sweetest herbs, all cut 

 when most vigorous, and dried so slowly as to 

 form a green and succulent fodder; he found 

 in it scarcely any ears or blossoms, or hard and 

 woody stems, but some mixture of bitter herbs, 

 probably useful to render the rest more whole- 

 some."-t 



" Although," says Kirby, " ants during the 

 cold winters in this country remain in a state of 

 torpidity, and have no need of food, yet in 

 warmer regions during the rainy seasons, when 

 they are probably confined to their nests, a store 

 of provisions may be necessary for them. Now 

 although the rainy season, at least in America, 

 is a season in which insects are full of life, yet 

 the observation that ants may store up provi- 

 sions in warm countries is confirmed by an 

 account sent me by Colonel Sykes, with respect 



* Introduction to Entomology, vol. ii. p. 438. 

 t Ib. p. 507. 



to another species which appears to belong to 

 the same genus as the celebrated ants of visi- 

 tation, by which the houses of the inhabitants 

 of Surinam were said to be cleared periodically 

 of their cock-roaches, mice, and even rats. The 

 present species has been named by Mr. Hope 

 the provident ant. These ants, after long-con- 

 tinued rains during the monsoon, were found 

 to bring up and lay upon the earth on a fine 

 day, their stores of grass seeds and grains of 

 Guinea corn, for the purpose of drying them. 

 Many scores of these hoards were frequently 

 observable on the extensive parade at Poona."* 

 The great and important instinct of migration 

 is another means by which the lives of many 

 animals are preserved during winter. The 

 number of species of birds, which pass the 

 summer to bring forth their young in this 

 country, but disappear from it in autumn, and 

 are known to spend the winter in the south of 

 Europe or Africa, has been stated at not less 

 than five-sixths of the whole number resident 

 here during the summer, and these are replaced 

 by many other species, chiefly aquatic birds and 

 waders, but likewise the fieldfares, redwings, 

 starlings, &c. which have brought forth their 

 young in the colder climates, and return here 

 for the winter. There are others, as the crane 

 and stork, which perform similar migrations, 

 but are rarely seen in this country. The migra- 

 tions of the larger birds from the northern 

 regions are chiefly performed in large bodies, 

 forming angular lines, very high in the air; 

 those of the smaller birds of passage, swallows, 

 singing birds, &c. that go southwards from 

 hence, seem to take place less regularly, and 

 have been less accurately observed. There are 

 also many annual migrations from one part of 

 this country to another, in spring and autumn, 

 as of the plovers and lapwings, curlews, ring 

 ouzels, &c. It is still doubtful with what 

 sensations the propensity to perform these peri- 

 odical migrations is chiefly connected, whether 

 with changes of temperature, or deficiency of 

 food, or with the changes of the sexual desire, 

 (as maintained by Jenner.f) But it is certain 

 that the migrations take place while the tem- 

 perature is still such as is well borne by the 

 animals ; indeed of most of the species of 

 birds of passage some individuals are frequently 

 observed not to migrate ; J and it is equally 

 certain that most of the birds of passage do not 

 gradually withdraw, as if following the gradual 

 changes of the food on which they live, but 

 go oft' suddenly, and perform their voyages, par- 

 ticularly in autumn, so rapidly, as to be much 

 exhausted and emaciated at the end of them ; 

 so that it is certainly not under the influence of 

 sensations gradually changing and tending to 

 partial and successive changes of place, but 

 under that of a strong determination, overcom- 

 ing the motives to action which are usually 

 predominant, and commanding strenuous and 

 painful exertion at a time when no great incon- 

 venience is felt, that these voyages are per- 



* Vol. ii. p. 344. 



i Phil. Trans. 1824. 



$ Sec Darwin, Zoouomia, sect. xvi. 12. 



