The Ingenious and Enduring Craft of Predation

“ Its head, flat and square, is armed with two moveable crooked horns, whose singular structure shews how admirable Nature is, even in the least of her works.
This insect is the most subtle and dangerous enemy the ant has; the plans which he forms to ensnare his prey, are very ingenious. He mines a portion of land in the form of a funnel, at the bottom of which he waits to seize the ants, which coming by chance to the edge of the precipice, are thence hurried down to their merciless foe. ”

“ This is exactly what happens in nature when a snare is constructed across chasms otherwise impassable, and it may be imagined that the spider regards as very valuable landed property the foundation lines of such a web, for, if destroyed, the direction or absence of the wind might prevent their renewal for days. They are accordingly made strong by repeated journeys, and are used as the framework of successive snares, till accident at length destroys them. ”

“ Many spiders spin webs to capture their prey. However spiders also have other means of capturing their prey. Some spiders spit a sticky web onto their prey. Others live in burrows with trapdoors. Whenever they feel hungry they come out and catch an unsuspecting insect. One species attaches a sticky drop to one end of its silken thread and holds it with its first three pairs of legs. When an insect passes by, the spider waves the thread at the insect and ropes it in, as it were.
Some spiders sit on flowers and catch insects that come to collect nectar. ”

“ Buried among the hairs is the entrance to the trap. Swimming about in search of food or in an attempt to escape from enemies, some minute crustacean or insect larva will push in among the hairs. Spying the entrance, it will dart forward and striking the almost transparent door it will unwittingly pass into the trap. ”

“ The trap must have been independently developed in the two cases, and could only have succeeded with such very stupid, unintelligent creatures as the flies and midges.
From plants that imprison insects to plants that devour insects alive is a natural transition. The giant who keeps a dungeon is first-cousin to the ogre who swallows down his captives entire. ”

“ The spider-mind acquires a faculty of memory, and, with it, a singular skill of analysis and synthesis, taking apart and putting together in different relations the meshes of its trap. Man had in the beginning no power of analysis or synthesis approaching that of the spider, or even of the honey-bee; he had acute sensibility to the higher forces. Fire taught him secrets that no other animal could learn; running water probably taught him even more, especially in his first lessons of mechanics ”

“ When an animal, even a small bird, steps upon the twigs, the two pegs fall asunder, and the beam drops, killing the animal under it. If it be set for a beast of prey, bait is laid beside the triggers; all other kinds of game are simply guided to the trap by the direction of the fence. In many woods all the haunts, paths, and clear spaces are beset with these traps in hundreds and thousands, so that the huntsman is often compensated by abundant booty for the slight trouble which it takes to arrange his effective apparatus. Grouse, hares, squirrels, and ermine are the commonest victims ”

“ Unlike most other spiders, it hunts its game without the aid of webs or snares. It does, however, possess the ability to spin the silk which we have all seen other spiders make, for, in digging its hole, it makes neat little packages of the dirt it has scraped up, bound together with silk and slime from its mouth, and flips them to one side out of the way. When it comes to hunting, it makes sure that it can pounce on its prey, by building the entrance of its hole about two inches in diameter and up from the surface an inch or so, so that it can spread its legs for the leap. ”

“ The Bird Catching Spider is a gigantic spider native to Surinam and elsewhere. It preys upon insects and small birds, which it hunts for and pounces upon. It is about two inches long, very hairy, and almost black; its feet when spread out occupy a surface of nearly a foot in diameter.
Hunter-Spiders. A great many of this species construct no webs, but use their silk merely for lining their dwellings—which are commonly underground—or the construction of protective investments for the eggs. Such forms simply stalk their prey, seizing the victims, when near enough, by a sudden [232] spring. ”

“ Up and down the fallen timber would stalk gigantic black ants, one inch in length, provided with most formidable stings, and disdaining to run away from danger. They are slow and stately in their movements, seeming to prey solely on the slow-moving wood-borers, which they take at a great disadvantage when half buried in their burrows, and bear off in their great jaws. They appear to use their sting only as a defensive weapon; but other smaller species that hunt singly, and are very agile, use their stings to paralyse their prey. ”

“ When things get started happening, they are quite apt to keep it up for awhile, as if events invited events. A large hunting spider, creeping among the grass and weeds, discovered the handsome cluster of the sarracenia. She was one of the few creatures who had learned the secret of the pitcher-plant and knew how to turn it to account. More than once had she found easy prey in some trapped insect struggling near the top of a well-filled pitcher. ”

“ These great spiders of the tropics hunt for prey in much the same way. Only instead of catching flies on walls they prowl [391] about the branches of trees in search of small birds, springing upon them when they are roosting at night, and killing them almost immediately by a smart bite from their venomous fangs. These spiders, of course, are very large. Indeed, the body of a full-grown bird-spider is as big as a man's fist, while its great hairy legs cover nearly a square foot of ground when they are fully spread out. ”

“ The animal needs a constant supply of water, and if this can be had, broken and intricate ravine systems suit it as well as thickets or forest land. Its partiality for swamps depends upon their productions, and the fact that game is apt to be found in them. Independently of special considerations of any kind, the propensity to conceal itself is a natural and necessary outgrowth of the habits and character of all predatory creatures. ”

“ This hole is not to serve as a trap, that is to say that the proprietor has no intention of causing any pedestrian to roll to the bottom. It is simply a place of concealment in which he awaits the propitious moment. No creature is more patient than this insect, and no delay discourages him. As soon as some small animal approaches his hiding-place he throws himself on it impetuously, kills it, and devours it. ”

“ It always makes its attacks by stealth, and if possible from behind, and relies on two or three tremendous springs to bring it on the doomed creature's back. It uses its claws as well as its teeth in holding and killing the prey. If possible it always seizes a large animal by the throat, whereas the wolf's point of attack is more often the haunch or flank. Small deer or sheep it will often knock over and kill, merely using its big paws ”

“ The baited ambush. — A variety of ambush which brings this method of hunting to considerable perfection lies in inciting the prey to approach the hiding-place instead of trusting to chance to bring it there. In such circumstances Man places some allurement in the neighbourhood — that is to say, one of the foods preferred by the desired victim, or at least some object which recalls the form of that food, as, for example, an artificial fly to obtain possession of certain fishes. ”

“ They seize it, some by its head, some by its tail; it struggles, it writhes, and sometimes succeeds in freeing itself from its enemies; but they do not consider themselves beaten, and attack it again. Little by little it becomes stupefied from the discharges of formic acid the ants throw out from their bodies, and presently it succumbs to their renewed forces. Finally, though the struggle may last an hour or more, it is borne to the ant-heap and disappears, to be devoured by the inmates. ”

“ Its eight legs are disposed in an oval upon the cephalothorax, and are long and slender, each having seven joints. They are suited for firmly grasping its prey, and, when stretched out, while the creature is watching or moving, they cause the weight of the body to be distributed over a large surface of the fragile web. All this preparation for war is not thrown away, as spiders are plucky and desperate fighters. Although consummate strategists, and availing themselves to the utmost of cunning snares, they are ever ready for an attack, and fight ferociously. ”

“ But flowers prefer the visits of moths and butterflies; as ants are of no service to them in scattering pollen, they do not wish them to get their honey. Some of the flowers have found out that ants, though so industrious by reputation, are lazy about getting out early in the morning for they dislike the dew very much. Hence by 9 o'clock these wary flowers have closed their doors. Others take the precaution to baffle ant visitors by holding an extra quantity of dew on the basins of their leaves, while still others exude a sticky fluid from their stems which glues the poor ants to the spot. ”

“ Still others feed on other spiders only and are called pirate spiders. A few spiders live on the webs of other spiders: they are too small to be eaten by their host. They eat the small prey that get caught in the web, thus keeping it tidy.
Spiders also have amazing defence mechanisms. Some spiders camouflage themselves as a bird dropping. Others, as a dried yellow or black rotting leaf or twig. And yet others resemble ants which are often rejected by birds, reptiles and other insects. Some are even able to change colour and shape, to some extent, to match their surroundings. ”

“ I have heard this urged as a reason for believing that they could not have been produced by natural selection, because a much less degree of resemblance would have protected the mimetic species. To this it may be answered, that natural selection not only tends to pick out and preserve the forms that have protective resemblances, but to increase the perceptions of the predatory species of insects and birds, so that there is a continual progression towards a perfectly mimetic form. ”

“ Trapping in itself is an art. Many of the wild creatures are exceedingly wary and the trapper must match his reason against the instinct, the natural wariness and the acquired knowledge of the animals. This wariness alone has saved some species of animals from extinction, and although man is superior to all brute life, such intelligent animals as the fox and the wolf frequently prove a match for the most expert of trappers. ”

“ Just as the most rudimentary method of attack is simple pursuit, so the most simple and natural method of defence is flight; but if very fleet animals like hares, gazelles, and deer can escape by simply exerting their maximum rapidity, it is not always thus, and certain species exercise in flight perfected methods appropriate to circumstances, and so raise this method of defence to an art. ”

“ But even when the war is open and declared, as between a raptorial species and its victims, the former is manifestly driven by necessity. And in this case the species preyed on are endowed with peculiar sagacity to escape its persecutions; so that the war is not one of extermination, but, as in a border war, the invader is satisfied with carrying off the weak and unwary stragglers. ”

“ When this animal had once ceased to use so good a weapon as its teeth in defending itself, degenerating at the same time into a slow-moving creature, without fear and without cunning, the strength and vileness of its odour would be continually increased by the cumulative process of natural selection: and how effective the protection has become is shown by the abundance of the species throughout the whole American continent. It is lucky for mankind--especially for naturalists and sportsmen--that other species have not been improved in the same direction. ”

“ The spider alone yields not to panic, but uses common sense—may not one say reason? Some that were observed, upon the first scent of danger, took to their long legs, and having two more of them than any insect, and no inclination to stop for luncheon, soon put a long distance between themselves and the savage little hosts. Others, not caring to run, neither to be eaten, simply swung themselves out into the universe by their magic thread, and there hung between heaven and earth, like a certain legendary coffin, till the uncivil enemy had passed by. ”

“ The success of procryptic coloration depends, however, very largely upon stillness, and the instinct to keep stationary without moving a limb is a marked characteristic of all spiders unless engaged in hunting or fleeing from imminent danger. The instinct reaches its highest development in the phenomenon miscalled “death feigning.” Spiders of various families will, when alarmed, lie absolutely still with legs tucked up and allow themselves to be pushed and rolled, and handled in various ways without betraying that they are alive by the slightest movement. ”

“ If the process of natural selection was to be applied, according to a very frequent method, as universal, then birds arising from these white and prominent eggs would seem in course of time to be doomed to destruction. But we find nothing of the kind. Natural selection is here replaced by the evolution of intelligence or active mimicry. True, it may be argued that birds laying white eggs would become extinct without they had gradually acquired the intelligent or automatic powers of concealment through a process of natural selection. ”

“ The mocking forms, on the other hand, that inhabit the same district, are comparatively rare, and belong to rare groups; hence, they must suffer habitually from some danger, for otherwise, from the number of eggs laid by all butterflies, they would in three or four generations swarm over the whole country. Now if a member of one of these persecuted and rare groups were to assume a dress so like that of a well-protected species that it continually deceived the practised eyes of an entomologist, it would often deceive predaceous birds and insects, and thus often escape destruction. ”