INSTINCT. 



or llama before they enter on the deserts, and 

 which enable them subsequently to subsist 

 without water for many days. 



But the instincts by which animals are en- 

 abled to search for and obtain food may be 

 easily supposed to be much more numerous 

 and varied than those by which they merely 

 seize and swallow it, and in fact furnish the 

 conditions by which the varieties of the whole 

 structure of animals are chiefly determined. 

 Probably the greatest number of animals are 

 nourished by the vegetable world in the living 

 or dead state, and are continually guided by 

 sensations, to which instinctive efforts are at- 

 tached, i. e. by appetites, in the selection of 

 food, which may in general be found and 

 seized without much difficulty. But through- 

 out the whole animal kingdom, from the mi- 

 croscopic animalcules up to the largest of 

 the Mammalia, a very great number of carni- 

 vorous animals are found, who subsist on, and 

 continually repress the numbers of, the herbi- 

 vorous tribes; and it may easily be supposed 

 that the instincts implanted in these animals, 

 which oppose and counteract the varying efforts 

 at self-preservation already mentioned, will be 

 more varied, and bear more marks of contri- 

 vance and ingenuity. Accordingly, from the 

 numerous Vorticellae, or other animalcules, of 

 the order Rotatoria, which excite currents in 

 the water around them, and so attract into 

 their stomachs many of the smaller ani- 

 malcules, up to the lion, the whale, or the 

 eagle, we find an infinite number of con- 

 trivances and instinctive propensities, served 

 by organs, by which the predaceous animals, 

 of all the orders, are enabled to prey on the 

 others. The Polype, Echinus, and Actinia, for 

 example, among the Zoophyta, seize their 

 prey, as it is brought to them by the waves, 

 with their numerous tentacula ; the Entozoa, 

 and the leech and other of the Annelides, have 

 the faculty and the necessary instinct of attach- 

 ing themselves to the larger animals in the 

 situations which suit them, as the Cirrhipedes 

 or barnacles do to vegetable substances. The 

 cuttle-fish and other predaceous Mollusca have 

 legs furnished with admirably constructed 

 suckers and powerful jaws, and most of the 

 Crustacea have claws and mandibles, suf- 

 ficient to enable them to seize and destroy ma- 

 rine animals of very considerable size ; and it 

 is unnecessary to enlarge on the powerful 

 means of destruction, or on the instincts guid- 

 ing their use, which are seen in many genera 

 of each of the classes of vertebrated animals. 

 There is often a peculiar instinct guiding 

 each of the Carnivorous Mammalia to the 

 part of the body of its victim where it can 

 most easily inflict a mortal wound, to the 

 throat in the case of a large animal, to the head 

 in that of a small one, of which the cranium 

 may be pierced. In the greater number of 

 them, however, the instinctive actions by which 

 their prey is obtained are distinguished only by 

 power and violence ; and although much con- 

 trivance is employed for adapting the different 

 parts of the structure to the habits and des- 

 tination of the animals, there is little apparent 



ingenuity in the modes in which the animals 

 perform their office in creation. The attitude 

 and gesture of the cat, the pointer, or the tiger, 

 " slow stealing with crouched shoulders on 

 his prey," is an example of instinctive con- 

 trivance preliminary to the act of violence. 

 The aspect and expression of many carnivo- 

 rous animals, not only of the Mammalia and 

 birds, but of the shark, the cuttle-fish, the 

 scorpion, the tiger-beetle, &c., are so adapted 

 to the feelings and instincts of the animals on 

 which they feed, as often to deprive them of 

 the power of flight or resistance; and it is 

 maintained by many, that some of the predace- 

 ous animals have the power of fascinating their 

 prey by merely fixing their eyes on them. 

 Many have ascribed this power to the serpent ; 

 and Mr. Kirby asserts it with confidence of 

 the fox.* A few only of the predaceous ani- 

 mals, as the dog and wolf, have the instinct 

 of associating together for procuring their prey. 

 It has been stated that the pelican and the 

 dog-fish have a similar instinct.f 



But the more striking indications of con- 

 trivance in the actions prompted by this in- 

 stinct are to be found in some of the less pow- 

 erful of the carnivorous tribes. The Lophius 

 Piscatorius or fishing-frog, although a large 

 fish, having no strength or speed, obtains its 

 prey by stratagem, plunging itself in mud, or 

 covering itself with sea-weed: " it lets no part 

 of it be perceived except the extremity of the 

 filaments that fringe its body, which it agitates 

 in different directions, so as to make them ap- 

 pear like worms. The fishes, attracted by this 

 apparent prey, approach and are seized by a 

 single movement of the fishing-frog, and swal- 

 lowed by his enormous throat, and retained by 

 the innumerable teeth by which it is armed." J 

 A still more singular art is practised by the 

 Choetodon rostratus, which feeds on flies, and, 

 as Sir Charles Bell states, actually takes aim 

 at them, and shoots them with a drop of water. 

 The instinct of the myrmecophaga or ant-eater, 

 which protrudes the tongue to allure flies to 

 settle on it, and then suddenly retracts it to 

 devour them, also deserves notice. A more 

 complex art is practised by the ant-lion, which 

 digs a pitfall in the track usually followed by 

 ants, and conceals itself in the bottom of it, 

 waiting for its prey. But of all contrivances 

 in the animal creation for procuring food, the 

 most complex and artificial are those of the 

 different genera of spiders, equally curious on 

 account of the peculiar organs by which they 

 spin their webs, as of the peculiar and varied 

 instincts by which they are guided in using 

 them. || For example, " any common black 

 and white spider (Salticus Scenicus), which 

 may always be seen in summer on sunny rails, 

 &c., when it spies a fly at a distance, ap- 

 proaches softly, step by step, and seems to 

 measure his distance from it by the eye; then 

 if he judges that he is within reach, first fixing 



* Vol. ii. p. 2fi9. 



t See Darwin's Zoon. vol. i. p. 229, 249. 



J See Kirby, vol. ii. p. 406, and pi. xiii. 



$ Bridirewater Treatise, p. 200. 



|| See Kirby, vol. ii. p. 184 and 286. 



