Jungle days

Sloths have no right to be living on the earth today; they would be fitting inhabitants of Mars, where a year is over six hundred days long. In fact they would exist more appropriately on a still more distant planet where time—as we know it—creeps and crawls instead of flies from dawn to dusk. Years ago I wrote that sloths reminded me of nothing so much as the wonderful Rath Brother athletes or of a slowed-up moving picture, and I can still think of no better similes.

Sloths live altogether in trees, but so do monkeys, and the chief difference between them would seem to be that the latter spend their time pushing against gravitation while the sloths pull against it. Botanically the two groups of animals are comparable to the flower which holds its head up to the sun, swaying on its long stem, and, on the other hand, the over-ripe fruit dangling heavily from its base. We ourselves are physically far removed from sloths—for while we can point with pride to the daily achievement of those ambulatory athletes, floor-walkers and policemen, yet no human being can cling with his hands to a branch for more than a comparatively short time.

Like a rainbow before breakfast, a sloth is a surprise, an unexpected fellow breather of the air of our planet. No one could prophesy a sloth. If you have an imaginative friend who has never seen a sloth and ask him to describe what he thinks it ought to be like, his uncontrolled phrases will fall far short of reality. If there were no sloths, Dunsany would hesitate to put such a creature in the forests of Mluna, Marco Polo would deny having seen one, and Munchausen would whistle as he listened to a friend’s description.

A scientist—even a taxonomist himself—falters when he mentions the group to which a sloth belongs. A taxonomist is the most terribly accurate person in the world, dealing with unvarying facts, and his names and descriptions of animals defy discretion, murder imagination. Nevertheless when next you see a taxonomist disengaged, approach him boldly and ask him in a tone of quarrelsome interest to what order of Mammalia sloths belong. If an honest conservative he will say, “Edentata,” which, as any ancient Greek will tell you, means a toothless one. Then if you wish to enrage and nonplus the taxonomist, which I think no one should, as I am one myself, then ask him Why? or, if he has ever been bitten by any of the eighteen teeth of a sloth?

The great savant Buffon in spite of all his genius, fell into most grievous error in his estimation of a sloth. He says, “The inertia of this animal is not so much due to laziness as to wretchedness; it is the consequence of its faulty structure. Inactivity, stupidity, and even habitual suffering result from its strange and ill-constructed conformation. Having no weapons for attack or defense, no mode of refuge even by burrowing, its only safety is in flight.... Everything about it shows its wretchedness and proclaims it to be one of those defective monsters, those imperfect sketches, which Nature has sometimes formed, and which, having scarcely the faculty of existence, could only continue for a short time and have since been removed from the catalogue of living beings. They are the last possible term amongst creatures of flesh and blood, and any further defect would have made their existence impossible.”

If we imagine the dignified French savant himself, naked, and dangling from a lofty jungle branch in the full heat of the tropic sun, without water and with the prospect of nothing but coarse leaves for breakfast, dinner and all future meals, an impartial onlooker who was ignorant of man’s normal haunts and life could very truthfully apply to the unhappy scientist, Buffon’s own comments. All of his terms of opprobrium would come home to roost with him.

A bridge out of place would be an absolutely inexplicable thing, as would a sloth in Paris, or a Buffon in the trees. As a matter of fact it was only when I became a temporary cripple myself that I began to appreciate the astonishing lives which sloths lead. With one of my feet injured and out of commission I found an abundance of time in six weeks to study the individuals which we caught in the jungle near by. Not until we invent a superlative of which the word “deliberate” is the positive can we define a sloth with sufficient adequateness and briefness. I dimly remember certain volumes by an authoress whose style pictured the hero walking from the door to the front gate, placing first the right, then the left foot before him as he went. With such detail and speed of action might one write the biography of a sloth.

Ever since man has ventured into this wilderness, sloths have aroused astonishment and comment. Four hundred years ago Gonzala de Oviedo sat him down and penned a most delectable account of these creatures. He says, in part: “There is another strange beast the Spaniards call the Light Dogge, which is one of the slowest beasts and so heavie and dull in mooving that it can scarsely goe fiftie pases in a whole day. Their neckes are high and streight, and all equall like the pestle of a mortar, without making any proportion of similitude of a head, or any difference except in the noddle, and in the tops of their neckes. They have little mouthes, and moove their neckes from one side to another, as though they were astonished: their chiefe desire and delight is to cleave and sticke fast unto Trees, whereunto cleaving fast, they mount up little by little, staying themselves by their long claws. Their voice is much differing from other beasts, for they sing only in the night, and that continually from time to time, singing ever six notes one higher than another. Sometimes the Christian men find these beasts, and bring them home to their houses, where also they creepe all about with their natural slownesse. I could never perceive other but that they love onely of Aire: because they ever turne their heads and mouthes toward that part where the wind bloweth most, whereby may be considered that they take most pleasure in the Aire. They bite not, nor yet can bite, having very little mouthes: they are not venemous or noyous any way, but altogether brutish, and utterly unprofitable and without commoditie yet known to men.”

It is difficult to find adequate comparisons for a topsy-turvy creature like a sloth, but if I had already had synthetic experience with a Golem, I would take for a formula the general appearance of an English sheep dog, giving it a face with barely distinguishable features and no expression, an inexhaustible appetite for a single kind of coarse leaf, a gamut of emotions well below the animal kingdom, and an enthusiasm for life excelled by a healthy sunflower. Suspend this from a jungle limb by a dozen strong hooks, and—you would still have to see a live sloth to appreciate its appearance.

At rest, curled up into an arboreal ball, a sloth is indistinguishable from a cluster of leaves; in action, the second hand of a watch often covers more distance. At first sight of the shapeless ball of hay, moving with hopeless inadequacy, astonishment shifts to pity, then to impatience and finally, as we sense a life of years spent thus, we feel almost disgust. At which moment the sloth reaches blindly in our direction, thinking us a barren, leafless, but perhaps climbable tree, and our emotions change again, this time to sheer delight as a tiny infant sloth raises its indescribably funny face from its mother’s breast and sends forth the single tone, the high, whistling squeak, which in sloth intercourse is song, shout, converse, whisper, argument and chant. Separating him from his mother is like plucking a bur from one’s hair, but when freed, he contentedly hooks his small self to our clothing and creeps slowly about.

Instead of reviewing all the observations and experiments which I perpetrated upon sloths, I will touch at once the heart of their mysterious psychology, giving in a few words a conception of their strange, uncanny minds. A bird will give up its life in defending its young; an alligator will not often desert its nest in the face of danger; a male stickleback fish will intrepidly face any intruder that threatens its eggs. In fact, at the time when the young of all animals are at the age of helplessness, the senses of the parents are doubly keen, their activities and weapons are at greatest efficiency for the guarding of the young and the consequent certainty of the continuance of their race.

The resistance made by a mother sloth to the abstraction of its offspring is chiefly the mechanical tangling of the young animal’s tiny claws in the long maternal fur. I have taken away a young sloth and hooked it to a branch five feet away. Being hungry it began at once to utter its high, penetrating penny whistle. To no other sound, high or low, with even a half tone’s difference does the sloth pay any heed, but its dim hearing is attuned to just this vibration. Slowly the mother starts off in what she thinks is the direction of the sound. It is the moment of moments in the life of the young animal. Yet I have seen her again and again on different occasions pass within two feet of the little chap, and never look to right or left, but keep straight on, stolidly and unvaryingly to the high jungle, while her baby, a few inches out of her path, called in vain. No kidnapped child hidden in mountain fastness or urban underworld was ever more completely lost to its parent than this infant, in full view and separated by only a sloth’s length of space.

A gun fired close to the ear of a sloth will usually arouse not the slightest tremor; no scent of flower or acid or carrion causes any reaction; a sleeping sloth may be shaken violently without awakening, the waving of a scarlet rag, or a climbing serpent a few feet away brings no gleam of curiosity or fear to the dull eyes; an astonishingly long immersion in water produces discomfort but not death. When we think what a constant struggle life is to most creatures, even when they are equipped with the keenest of senses and powerful means of offense, it seems incredible that a sloth can hold its own in this overcrowded tropical jungle.

From birth to death it climbs slowly about the great trees, leisurely feeding, languidly loving, and almost mechanically caring for its young. On the ground a host of enemies await it, but among the higher branches it fears chiefly occasional great boas, climbing jaguars and, worst of all, the mighty talons of harpy eagles. Its means of offense is a joke—a slow, ineffective reaching forward with open jaws, a lethargic stroke of arm and claws which anything but another sloth can avoid. Yet the race of sloths persists and thrives, and in past years I have had as many as eighteen under observation at one time.

A sloth makes no nest or shelter; it even disdains the protection of dense foliage. But for all its apparent helplessness it has a cheval-de-frise of protection which many animals far above it in intelligence might well envy. Its outer line of defense is invisibility—and there is none better, for until you have seen your intended prey you can neither attack nor devour him. No hedgehog or armadillo ever rolled a more perfect ball of itself than does a sloth, sitting in a lofty, swaying crotch with head and feet and legs all gathered close together inside. This posture, to an onlooker, destroys all thought of a living animal, but presents a very satisfactory white ants’ nest or bunch of dead leaves. If we look at the hair of a sloth we will see small, grey patches along the length of the hairs—at first sight bits of bark and débris of wood. But these minute, scattered particles are of the utmost aid to this invisibility. They are a peculiar species of alga or lichen-like growth which is found only in this peculiar haunt, and when the rains begin and all the jungle turns a deep, glowing emerald, these tiny plants also react to the welcome moisture and become verdant—thus throwing over the sloth a protecting, misty veil of green.

Even we dull-sensed humans require neither sight nor hearing to detect the presence of an animal like the skunk; in the absolute quiet and blackness of midnight we can tell when a porcupine has crossed our path, or when there are mice in the bureau drawers. But a dozen sloths may be hanging to the trees near at hand and never the slightest whiff of odor comes from them. A baby sloth has not even a baby smell, and all this is part of the cloak of invisibility. The voice, raised so very seldom, is so ventriloquil, and possesses such a strange, unanimal-like quality that it can never be a guide to the location much less to the identity of the author. Here we have three senses, sight, hearing, smell, all operating at a distance, two of them by vibrations, and all leagued together to shelter the sloth from attack.

But in spite of this dramatic guard of invisibility the keen eyes of an eagle, the lapping tongue of a giant boa, and the amazing delicacy of a jaguar’s sense of smell break through at times. The jaguar scents sign under the tree of the sloth, climbs eagerly as far as he dares and finds ready to his paw the ball of animal unconsciousness; a harpy eagle half a mile above the jungle sees a bunch of leaves reach out a sleepy arm and scratch itself—something clumps of leaves should not do. Down spirals the great bird, slowly, majestically, knowing there is no need of haste, and alights close by the mammalian sphere. Still the sloth does not move, apparently waiting for what fate may bring—waiting with that patience and resignation which comes only to those of our fellow creatures who cannot say, “I am I!” It seems as if Nature had deserted her jungle changeling, stripped now of its protecting cloak.

The sloth however has never been given credit for its powers of passive resistance, and now, with its enemy within striking distance, its death or even injury is far from a certainty. The crotch which the sloth chooses for its favorite outdoor sport, sleep, is unusually high up or far out among the lesser branches, where the eight claws of the eagle or the eighteen of a jaguar find but precarious hold. In order to strike at the quiescent animal the bird has to relinquish half of its foothold, the cat nearly one quarter. If the victim were a feathery bush turkey or a soft-bodied squirrel, one stroke would be sufficient, but this strange creature is something far different. In the first place it is only to be plucked from its perch by the exertion of enormous strength. No man can seize a sloth by the long hair of the back and pull it off. So strong are its muscles, so vise-like the grip of its dozen talons that either the crotch must be cut or broken off or the long claws unfastened one by one. Neither of these alternatives is possible to the attacking cat or eagle. They must depend upon crushing or penetrating power of stroke or grasp.

Here is where the sloth’s second line of defense becomes operative. First, as I have mentioned, the swaying branch and dizzy height is in his favor, as well as his immovable grip. To begin with the innermost defenses, while his jungle fellows, the ring-tailed and red howling monkeys, have thirteen ribs, the sloth may have as many as twenty; in the latter animal they are, in addition, unusually broad and flat, slats rather than rods. Next comes the skin which is so thick and tough that many an Indian’s arrow falls back without even scratching the hide. The skin of the unborn sloth is as tough and strong as that of a full-grown monkey. Finally we have the fur—two distinct coats, the under one fine, short and matted, the outer long, harsh and coarse. Is it any wonder that, teetering on a swaying branch, many a jaguar has had to give up after frantic attempts to strike his claws through the felted hair, the tough skin and the bony lattice-work which protect the vitals of this Edentate bur!

Having rescued our sloth from his most immediate peril let us watch him solve some of the very few problems which life presents to him. Although the cecropia tree, on the leaves of which he feeds, is scattered far and wide through the jungle, yet sloths are found almost exclusively along river banks, and, most amazingly, they not infrequently take to the water. I have caught a dozen sloths swimming rivers a mile or more in width. Judging from the speed of short distances, a sloth can swim a mile in three hours and twenty minutes. Their thick skin and fur must be a protection against crocodiles, electric eels and perai fish as well as jaguars. Why they should ever wish to swim across these wide expanses of water is as inexplicable as the migration of butterflies. One side of the river has as many comfortable crotches, as many millions of cecropia leaves and as many eligible lady sloths as the other! In this unreasonable desire for anything which is out of reach sloths come very close to a characteristic of human beings.

Even in the jungle sloths are not always the static creatures which their vegetable-like life would lead us to believe, as I was able to prove many years ago. A young male was brought in by Indians and after keeping it a few days I shaved off two patches of hair from the center of the back, and labelling it with a metal tag I turned it loose. Forty-eight days later it was captured near a small settlement of bovianders several miles farther up and across the river. During this time it must have traversed four miles of jungle and one of river.

The principal difference between the male and female three-toed sloths is the presence on the back of the male of a large, oval spot of orange-colored fur. To any creature of more active mentality such a minor distinction must often be embarrassing. In an approaching sloth, walking upside-down as usual, this mark is quite invisible, and hence every meeting of two sloths must contain much of delightful uncertainty, of ignorance whether the encounter presages courtship or merely gossip. But color or markings have no meaning in the dull eyes of these animals. Until they have sniffed and almost touched noses they show no recognition or reaction whatever.

I once invented a sloth island—a large circle of ground surrounded by a deep ditch, where sloths climbed about some saplings and ate, but principally slept, and lived for months at a time. This was within sight of my laboratory table, so I could watch what was taking place by merely raising my head. Some of the occurrences were almost too strange for creatures of this earth. I watched two courtships, each resulting in nothing more serious than my own amusement. A female was asleep in a low crotch, curled up into a perfect ball deep within which was ensconced a month-old baby. Two yards overhead was a male who had slept for nine hours without interruption. Moved by what, to a sloth, must have been a burst of uncontrollable emotion, he slowly unwound himself and clambered downward. When close to the sleeping beauty he reached out a claw and tentatively touched a shoulder. Even more deliberately she excavated her head and long neck and peered in every direction but the right one. At last she perceived her suitor and looked away as if the sight was too much for her. Again he touched her post-like neck, and now there arose all the flaming fury of a mother at the flirtatious advances of this stranger. With incredible slowness and effort she freed an arm, deliberately drew it back and then began a slow forward stroke with arm and claws. Meanwhile her gentleman friend had changed his position so the blow swept, or, more correctly passed, through empty air, the lack of impact almost throwing her out of the crotch. The disdained one left with slowness and dignity—or had he already forgotten why he had descended?—and returned to his perch and slumber, where I am sure, not even such active things as dreams came to disturb his peace.

The second courtship advanced to the stage where the Gallant actually got his claws tangled in the lady’s back hair before she awoke. When she grasped the situation she left at once and clambered to the highest branch tip followed by the male. Then she turned and climbed down and across her annoyer, leaving him stranded on the lofty branch looking eagerly about and reaching out hopefully toward a big, green iguana asleep on the next limb in mistake for his fair companion. For an hour he wandered languidly after her, then gave it up and went to sleep. Throughout these and other emotional crises no sound is ever uttered, no feature altered from its stolid repose. The head moves mechanically and the dull eyes blink slowly, as if striving to pierce the opaque veil which ever hangs between the brain of a sloth and the sights, sounds and odors of this tropical world. If the orange back spot was ever of any use in courtship, in arousing any emotion æsthetic or otherwise, it must have been in ages long past when the ancestors of sloths, contemporaries of their gigantic relatives the Mylodons, had better eyesight for escaping from sabre-toothed tigers, than there is need today.

The climax of a sloth’s emotion has nothing to do with the opposite sex or with the young, but is exhibited when two females are confined in a cage together. The result is wholly unexpected. After sniffing at one another for a moment, they engage in a slowed-up moving-picture battle. Before any harm is done one or the other gives utterance to the usual piercing whistle and surrenders. She lies flat on the cage floor and offers no defense while the second female proceeds to claw her, now and then attempting, usually vainly, to bite. It is so unpleasant that I have always separated them at this stage, but there is no doubt that in every case the unnatural affray would go on until the victim was killed. In fact I have heard of several instances where this actually took place.

A far pleasanter sight is the young sloth, one of the most adorable balls of fuzzy fur imaginable. While the sense of play is all but lacking his trustfulness and helplessness are most infantile. Every person who takes him up is an accepted substitute for his mother and he will clamber slowly about one’s clothing for hours in supreme contentment. One thing I can never explain is that on the ground the baby is even more helpless than his parents. While they can hitch themselves along, body dragging, limbs outspread, until they reach the nearest tree, a young sloth is wholly without power to move. Placed on a flat bit of ground it rolls and tumbles about, occasionally greatly encouraged by seizing hold of its own foot or leg under the impression that at last it has encountered a branch.

Sloths sleep about twice as much as other mammals and a baby sloth often gets tired of being confined in the heart of its mother’s sleeping sphere, and creeping out under her arm will go on an exploring expedition around and around her. When over two weeks old it has strength to rise on its hind legs and sway back and forth like nothing else in the world. Its eyes are only a little keener than those of the parent and it peers up at the foliage overhead with the most pitiful interest. It is slowly weaned from a milk diet to the leaves of the cecropia which the mother at first chews up for her offspring.

I once watched a young sloth about a month old and saw it leave its mother for the first time. As the old one moved slowly back and forth, pulling down cecropia leaves and feeding on them, the youngster took firm grip on a leaf stem, mumbling at it with no success whatever. When finally it stretched around and found no soft fur within reach it set up a wail which drew the attention of the mother at once. Still clinging to her perch, she reached out a forearm to an unbelievable distance and gently hooked the great claws about the huddled infant, which at once climbed down the long bridge and tumbled headlong into the hollow awaiting it.

When a very young sloth is gently disentangled from its mother and hooked on to a branch something of the greatest interest happens. Instead of walking forward, one foot after the other, and upside-down as all adult sloths do, it reaches up and tries to get first one arm then the other over the support, and to pull itself into an upright position. This would seem to be a reversion to a time—perhaps millions of years ago—when the ancestors of sloths had not yet begun to hang inverted from the branches. After an interval of clumsy reaching and wriggling about, the baby by accident grasps its own body or limb, and, in this case, convinced that it is at last anchored safely again to its mother, it confidently lets go with all its other claws and tumbles ignominiously to the ground.

The moment a baby sloth dies and slips from its grip on the mother’s fur, it ceases to exist for her. If it could call out she would reach down an arm and hook it toward her, but simply dropping silently means no more than if a disentangled bur had fallen from her coat. I have watched such a sloth carefully and have never seen any search of her own body or of the surrounding branches, or a moment’s distraction from sleep or food. An imitation of the cry of the dead baby will attract her attention, but if not repeated she forgets it at once.

It is interesting to know of the lives of such beings as this—chronic pacifists, normal morons, the superlative of negative natures, yet holding their own amidst the struggle for existence. Nothing else desires to feed on such coarse fodder, no other creature disputes with it the domain of the under side of branches, hence there is no competition. From our human point of view sloths are degenerate; from another angle they are among the most exquisitely adapted of living beings. If we humans, together with our brains, fitted as well into the possibilities of our own lives we should be infinitely finer and happier,—and, besides, I should then be able to interpret more intelligently the life and the philosophy of sloths!