The agile flea is another "homesteader," and if marked, its favorite resting-place on a dog or cat can easily be determined. After feeding, it will invariably return to a certain spot in order to enjoy its nap in peace; for, strange as it may seem, fleas are sound sleepers, and, what is more, seem to require a great deal of sleep.[104]

[104] All insects have periods of rest, during which they seem to be in a state of slumber. Their sleep may not be the physiological slumber of mammals, yet it effects a like purpose in all probability.--W.

Ants are, of the entire insect world, probably the most gifted home-finders. Time and again have I tested them in this, sometimes taking them what must have been, to these little creatures, enormous distances from their nests before freeing them. Of course the ants experimented with were marked, otherwise I could not have watched them successfully. When an ant is taken into new surroundings and set free, it at first runs here and there and everywhere. As soon, however, as it regains its equanimity and recovers from its fright, it turns toward home. At first it proceeds slowly, every now and then climbing tall blades of gra.s.s, and from these high places viewing the surrounding country in search of landmarks. As soon as it arrives among scenes partially familiar to it, it ceases to climb gra.s.s-blades or weeds, and accelerates its pace. When it arrives among well-known and accustomed surroundings it runs along at its utmost speed, and fairly races into its nest.

The burying beetle has a regular abode, to which it invariably returns after performing the offices of mortician to some defunct bird, beast, or reptile. This insect grave-digger, by the way, is remarkably expert at its business, and will bury a frog or a bird in a very short time.

As soon as it has buried the dead animal and deposited its eggs, it returns to its domicile beneath some log or stone.

Some snakes likewise are exceedingly domestic, and have their regular dens, to which they resort on occasions. The homing sense seems to be rather highly developed in them, for they can find their way back to their dens from great distances. I have had under observation for the past three years a garden snake, locally known as a "spreading viper"; this snake was brought to me by a friend[105] when it was only a foot long, so I have known her (for it is a female) ever since her infancy.

Owing to some antenatal accident, this reptile has a malformed head, so that I can readily recognize her at a distance of fifteen, twenty, or even thirty feet. Last year she reared her first brood of young, which I was fortunate enough to see with her on several occasions. Her den is on my lawn; and in the autumn of last year she conducted her brood to it, where they hibernated until spring. If I remember correctly, on the 29th of March she came out of her den accompanied by a dozen of her progeny, all but four (two pairs) of which I killed.[106] Snakes subserve a very useful purpose in the economy of nature, but it is well to keep them in limits, for, when very numerous, they become dangerous to young birds, especially after they have pa.s.sed the second year.

[105] Silas Rosenfield, Esq., Owensboro, Kentucky.

[106] The above was written in the summer of 1897. This interesting specimen was killed by a day-laborer who had been temporarily employed to a.s.sist the gardener. An autopsy revealed a bony tumor of the right orbital arch, which, from a little distance, looked like a horn.--W.

With the exception of the anthropoid apes all mammals possess the homing sense in a higher or lower degree; this is true also of birds.

Experiments with the nesting robin show conclusively that this bird can find its way back to its nest when carried fifty miles from its home and then set free among wholly unknown surroundings. The well-known exploits of the carrier-pigeon are so familiar that they scarcely need comment.

On May 3, 1898, two carrier-pigeons, en route for Louisville, rested for a time at Owensboro, Kentucky; these birds had been set free at New Orleans, Louisiana. The duck and the goose sometimes have this sense very highly developed. I once knew a goose to travel back home after having been carried in a covered basket for the distance of eighteen miles. A drake and duck have been known to return to their home after being carried a distance of nine miles by railway. Instances of home-returning by dogs, cats, horses, etc., are of such common occurrence that I hardly need call attention to them; the following instance is so unique, however, that I will present it:--

In the fall of 1861, a gentleman of Vincennes, Indiana, visited his father at Lebanon, Kentucky; when this gentleman started to return home, his father gave him a yoke of young steers, which he drove, _via_ Louisville, Kentucky, to Vincennes.

Shortly after his arrival at this last-mentioned town, the steers made their escape, swam the river at Owensboro, Kentucky, 160 miles below Louisville, Kentucky, and, in a week or so, were found one morning at the gate of their old home at Lebanon. Directed by their homing sense alone, these animals had made a journey of several hundred miles over a route they had never seen!

Fishermen are aware that certain fish choose localities for lurking-places, which they will share with no other fish. The black ba.s.s, and brook trout, and sturgeon, and goggle-eye are familiar examples of fish which have this habit.

On one occasion, I performed the following experiment: I took a black ba.s.s from its home near a sunken stump, and, after pa.s.sing a short piece of thread through the web of its tail and knotting it, replaced it in the river, two miles below its lurking-place. The next day I saw it in its old home, clearly recognizable by the bit of thread which waved to and fro in the clear water as the fish gently moved its tail!

In an examination of phenomena such as have been discussed in this chapter, ay, throughout this book, we must lay aside the dogmatic a.s.sertions of our superst.i.tious ancestors, who, to paraphrase Roscoe, "when awed by superst.i.tion, and subdued by hereditary prejudices, could not only a.s.sent to the most incredible proposition, but could act in consequence of these convictions, with as much energy and perseverance as if they were the clearest deductions of reason, or the most evident dictates of truth."[107]

[107] Roscoe, _Life of Leo X._, p. 3.

It will take the human race many, many years to unlearn, and to recover from the effects of the superst.i.tious cult of the shaman, who exists, not only among savages, but also in the most highly civilized races of the world! Superst.i.tion is the ant.i.thesis of knowledge; in fact, it is but another name for ignorance.

There is yet another exceedingly interesting psychical trait to be noticed in the lower animals, especially in insects; I refer to the instinctive habit, letisimulation (_letum_, death, and _simulare_, to feign). The word "instinctive" must not be used, however, when this stratagem is to be observed in the higher animals other than the opossum; for many of these animals sometimes make an occasional and a _rational_ use of it, as I will endeavor to show in the next chapter.

CHAPTER IX

LETISIMULATION

The feigning of death by certain animals for the purpose of deceiving their enemies, and thus securing immunity, is one of the greatest of the many evidences of intelligent action on their part.[108] Letisimulation (from _letum_, death, and _simulare_, to feign) is not confined to any particular family, order, or species of animals, but exists in many, from the very lowest to the highest. The habit of feigning death has introduced a figure of speech in the English language, and has done much to magnify and perpetuate the fame of the only marsupial found outside of Australasia and the Malayan Archipelago. "Playing 'possum" is now a synonym for certain kinds of deception. Man himself has known this to be an efficacious stratagem on many occasions. I have only to recall the numerous instances related by hunters who have feigned death, and have then been abandoned by the animals attacking them. I have seen this habit in some of the lowest animals known to science. Some time ago, while examining the inhabitants of a drop of pond water under a high-power lens, I noticed several rhizopods busily feeding on the minute buds of an alga. These rhizopods suddenly drew in their hair-like cilia and sank to the bottom, to all appearances dead. I soon discovered the cause in the presence of a water-louse, an animal which feeds on these animalcules. It likewise sank to the bottom, and, after examining the rhizopods, swam away, evidently regarding them as dead and unfit for food. The rhizopods remained quiet for several seconds, and then swam to the alga and resumed feeding. This was not an accidental occurrence, for several times since I have been fortunate enough to witness the same wonderful performance. There were other minute animals swimming in the drop of water, but the rhizopods fed on unconcernedly until the shark of this microscopic sea appeared. They then recognized their danger at once, and used the only means in their power to escape. Through the agency of what sense did these little creatures discover the approach of their enemies? Is it possible that they and other like microscopic animals have eyes and ears so exceedingly small that lenses of the very highest power cannot make them visible? Or are they possessors of senses utterly unknown to and incapable of being appreciated by man?

Science can neither affirm nor deny either of these suppositions. The fact alone remains that, through some sense, they discovered the presence of the enemy, and feigned death in order to escape.

[108] Instinct does not preclude intelligent ideation. In the lower animals death-feigning is undoubtedly instinctive; yet the recognition of danger, which sets in motion the phenomena of letisimulation, is undoubtedly due, primarily, to intelligent ideation in a vast majority of animals. Otherwise this earth would be a lifeless waste.--W.

There is a small fresh-water annelid which practises letisimulation when approached by the giant water-beetle.[109] This annelid, when swimming, is a slender, graceful little creature, about one-eighth of an inch long, and as thick as a human hair; but when a water-beetle draws near, it stops swimming, relaxes its body, and hangs in the water like a bit of cotton thread. It has a twofold object in this: in the first place, it hopes that its enemy will think it a piece of wood fibre, bleached alga, or other non-edible substance; in the second place, if the beetle be not deceived, it will nevertheless consider it dead and unfit for food. I do not mean to say that this process of ratiocination really occurs in the annelid; its intelligence goes no farther, probably, than conscious determination. In the beetle, however, conscious determination is merged into intelligent ideation, for its actions in the premises are self-elective and selective.

[109] _Dyticus marginalis._ Vide Furneaux, _Life in Ponds and Streams_, p. 325; foot-note for orthography.--W.

Letisimulation in this animal is by no means infrequent, for I have seen it feign death repeatedly. Any one may observe this stratagem if he be provided with a gla.s.s of clear water, a dyticus, and several of these little worms. The annelid is able to distinguish the beetle when it is several inches distant, and the change from an animated worm to a seemingly lifeless thread is startling in its exceeding rapidity.

Even an anemone, a creature of very low organization indeed, has acquired this habit. On one occasion, near St. John's, Newfoundland, I noticed a beautiful anemone in a pool of sea-water. I reached down my hand for it, when, presto! it shrivelled and shrunk like a flash into an unsightly green lump, and appeared nothing more than a moss-covered nodule of rock.

Very many grubs make use of this habit when they imagine themselves in danger. For instance, the "fever worm," the larva of one of our common moths,--the Isabella tiger-moth,--is a noted death-feigner, and will "pretend dead" on the slightest provocation. Touch this grub with the toe of your boot, or with the tip of your finger, or with a stick, and it will at once curl up, to all appearances absolutely without life.

A gentleman[110] recently told me that he saw the following example of letisimulation: One day, while sitting in his front yard, he saw a caterpillar crawling on the ground at his feet. The grub crawled too near the edge of a little pit in the sandy loam, and fell over, dragging with it a miniature avalanche of sand. It immediately essayed to climb up the north side of the pit, and had almost reached the top, when the treacherous soil gave way beneath its feet, and it rolled to the bottom. It then tried the west side, and met with a similar mishap.

Not discouraged in the least by its failure, it then tried the east side, and reached the very edge, when it accidentally disturbed the equilibrium of a corncob poised upon the margin of the pit, dislodged it, and fell with it to the bottom. The caterpillar evidently thought the cob was an enemy, for it at once rolled itself into a ball and feigned death. It remained quiescent for some time, but finally "came to life," tried the south side with triumphant success, and went on its way rejoicing. This little creature evinced conscious determination and a certain amount of reason; for it never tried the same side of the pit in its endeavors to escape, but always essayed a different side from that where it had encountered failure.

[110] Mr. George Mattingly, Owensboro, Kentucky.

Many free-swimming rotifers practise letisimulation when disturbed or when threatened by what they consider impending danger. If a "pitcher rotifer" (_Brachionus urceolaris_) be approached with a needle point, it will cease all motion and sink; the same is true of the "skeleton rotifer" (_Dinocharis pocillum_) and numerous others of this large family. Again, if a bit of alga on which there is a colony of "bell animalcules" (_Vorticellae_) be placed in a live box and then be examined with a moderate power, they can be seen to feign death. The rapidly vibrating cilia which surround the margin of the "bells" give rise to currents in the water which can be easily made out as they sweep floating particles toward the creatures' mouths and stomachs. If the table on which the microscope rests be rapped with the knuckles, the colony will disappear as if by magic. Now, what has become of it? If the microscope be readjusted, a group of tubercles will be observed on the alga; these are the vorticellae. They have simply coiled themselves upon their slender stems, have drawn in their cilia, and are feigning death.

In a few seconds one, and then another, will erect its stem; finally, the entire colony will "come to life" and resume feeding until they are again frightened, when they will at once resort to letisimulation.

Death-feigners are found in four divisions of animal life; viz., among insects, birds, mammals, and reptiles. Indeed, the most gifted letisimulants in the entire animal kingdom are to be observed in the great snake family. The so-called "black viper" of the middle United States is the most accomplished death-feigner that I have ever seen; its make-believe death struggles, in which it writhes and twists in seeming agony and finally turns upon its back and a.s.sumes _rigor mortis_, cannot be surpa.s.sed by any actor "on the boards" in point of pantomimic excellence.

I do not know of any fish which has acquired this strategic habit, but the evidence is not all in, and some day, perhaps, death-feigners may be found even among fishes.[111]

[111] Letisimulation, apparently, is not confined to animals; we see that certain plants have acquired a habit that is strikingly like death-feigning. We are apt to regard the plants as being non-sentient, yet there is an abundance of evidence in favor of the doctrine that vegetable life is, to a certain extent, percipient. Darwin has shown conclusively that plant life is as subject to the great law of evolution as animal life; he has also demonstrated, in his observations of insectivorous plants--the sun-dew (_Drosera rotundifolia_) especially--that these plants recognize at once the presence of foreign bodies when they are brought in contact with their sensitive glands;[A] he has likewise shown that plants, in the phenomenon known as circ.u.mnutation, evince a percipient sensitiveness that is as delicate as it is remarkable.[B] Hence, we need not feel surprised when we find, even in a plant, evidences of such a widespread stratagem as letisimulation. The champion death-feigner of the vegetable kingdom is a South American plant, _Mimosa pudica_. In the United States, where in some localities it has been naturalized, this plant is known as the "sensitive plant." A wild variety, _Mimosa strigilosa_, is native to some of the Southern States, but is by no means as sensitive as its South American congener. The last-mentioned plant is truly a vegetable wonder. At one moment a bed of soft and vivid green, the next a touch from a finger and, in the twinkling of an eye, it has changed into an unsightly tangle of seemingly dead and withered stems. In this case death-feigning seems absolutely successful as far as protection is concerned; for surely no gra.s.s-eating animal would touch this withered stuff, especially if there were other greens in the neighborhood. Death-feigning in plants, and kindred phenomena, are not due, however, to conscious determination; they are, in all probability, simply the result of reflex action.

[A] Darwin, _Insectivorous Plants_, Chap. V. _et seq._

[B] Darwin, _Power of Movement in Plants_, pp. 107-109.

Recently, I saw this stratagem perpetrated by a creature so low in the scale of animal life, and living amid surroundings so free from ordinary dangers, that, at first, I was loath to credit the evidence of my own perceptive powers; and it was only after long-continued observation that I was finally convinced that it was really an instance of letisimulation.

The animal in question was the itch mite (_Sarcoptes hominis_), which is frequently met with by physicians in practice, but which is rarely seen, although it is very often felt, by mankind, especially by those unfortunates who are forced by circ.u.mstances to dwell amid squalid and filthy surroundings. _Sarcoptes hominis_ is eminently a creature of filth, and is primarily a scavenger living on the dead and cast-off products of the skin. It is only when the desire for perpetuating its race seizes it that it burrows into the skin, thereby producing the intolerable itching which has given to it its very appropriate name. It is only the females that make tunnels in the skin; the males move freely over the surface of the epidermis. The females make tunnels or _cuniculi_ in the cuticle, in which they lay their eggs, and they can readily be removed from these burrows with a needle. While observing one of these minute _acarii_ through a pocket lens, as it crawled slowly on the surface of the skin, I wished to examine the under surface of its body. When I touched it with the point of a needle in attempting to turn it upon its back, it at once ceased to crawl and drew in its short, turtle-like legs toward its sides. It remained absolutely without motion for several seconds, and then slowly resumed its march. Again I touched it, and again it came to a halt, and took up its onward march only after several seconds had elapsed. Again and again I performed this experiment with like results; finally, the little traveller became thoroughly chilled, and, after a fruitless endeavor to again penetrate the skin, ceased all motion and died.

Many of the coleoptera are good letisimulants. The common tumble-bug (_Canthon laevis_), which may be seen any day in August rolling its ball of manure, in which are its eggs, to some suitable place of interment, is a remarkable death-feigner. Touch it, and at once it falls over, apparently dead. It draws in its legs, which become stiff and rigid; even its antennae are motionless. You may pick it up and examine it closely; it will not give the slightest sign of life. Place it on the ground and retire a little from it, and, in a few moments, you will see it erect one of its antennae and then the other. Its ears are in its antennae, and it is listening for dangerous sounds. Move your foot or stamp upon the ground, and back they go, and the beetle again becomes seemingly moribund.

This you may do several times, but the little animal, soon discovering that the sounds you make are not indicative of peril to it, scrambles to its feet and resumes the rolling of its precious ball. The habit of making use of this subterfuge is undoubtedly instinctive in this creature; but the line of action governing the use of the stratagem is evidently suggested by intelligent, correlated ideation.

Some animals feign death after exhausting all other means of defence.

The stink-bug (_pentatomid_) or bombardier bug (not the "bombardier beetle") has, on the sides of its abdomen near its middle c.o.xae ("hip bone"), certain bladder-like glands which secrete an acrid, foul-smelling fluid;[112] it has the power of ejecting this fluid at will.

[112] Comstock, _The Study of Insects_, p. 145.

When approached by an enemy, the stink-bug presents one side to the foe, crouching down on the opposite side, thus elevating its battery, and waits until its molester is within range; it then fires its broadside at the enemy. If the foe is not vanquished (as it commonly is), but still continues the attack, the bombardier turns and fires another broadside from the opposite side. If this second discharge does not prove efficacious (and I have rarely known it to fail), the little insect topples over, draws in its legs, and pretends to be dead.

Many a man has acted in like manner. He has fought as long as he could; then, seeing the odds against him, he has feigned death, hoping that his antagonist would abandon him and cease his onslaughts. The stink-bug in this seems to be governed and directed by _reason_, though the means used for defence must come under the head of instinct. Many a blind, instinctive impulse in the lower animals is, in all probability, aided and abetted by intelligent ratiocination when once it has made its appearance.

I have seen ants execute a like stratagem when overcome either by numbers or by stronger ants. They curl up their legs, draw down their antennae, and drop to the ground. They will allow themselves to be pulled about by their foes without the slightest resistance, showing no signs of life whatever. The enemy soon leaves them, whereupon the cunning little creatures take to their feet and hurry away.

The most noted and best known letisimulant among mammals is the opossum.

I have seen this animal look as if dead for hours at a time. It can be thrown down any way, and its body and limbs will remain in the position a.s.signed to them by gravity. It presents a perfect picture of death. The hare will act in the same way on occasions. The cat has been seen to feign death for the purpose of enticing its prey within grasping distance of its paws. In the mountains of East Tennessee (Chilhowee) I once saw a hound which would "play dead" when attacked by a more powerful dog than itself. It would fall upon its back, close its eyes, open its mouth, and loll out its tongue. Its antagonist would appear nonplussed at such strange conduct, and would soon leave it alone. Its master[113] declared that it had not been taught the trick by man, but that the habit was inherited or learned from its mother, which practised the same deception when hard pushed.[114]