Chapter IX: Part 9

Wingless, wormlike female beetles, (Lampyris hoctiluca, the European glow worm) were trying to attract their winged, lightless mates. Their nocturnal lovemaking as they clung to roadside weeds and bushes was a far from insignificant factor in the Normandy operations. The worms indicated not only the direction but the width of the roads, thus forestalling fatal accidents and preventing drivers from going astray into hostile territory. However, they doubtless proved of equal value to the enemy. These accommodating creatures, unknown to soldiers from across the Atlantic, should not be confused with our familiar fireflies.

_Worms in Medical History_

Earthworms have an important place in folk medicine, especially in the Near East. Muzhatu-L-qylut of Hamd Allah, an ancient Persian natural history, states: “Earthworms are red worms living in the damp earth. Baked and eaten with bread they reduce the size of stones in the bladder. When dried and eaten they cure the yellowness of jaundice. In difficult labor they bring on delivery immediately. Their ashes applied to the head with oil of roses make the hair to grow.”

Says a seventeenth century English medical treatise: “Earthworms are hot of nature and of them are a pressious oyntment made to close woundes; and if they be sodden in goose greece and styned it is a good oyntment for to drop into a dull hearing ear. Earthworms stamped are good for payned teeth. The oyle of earthworms be greatly commended for comforting of sinews, jointes, vaines and goute. They must be washed in white wine and the oyles of verbascum or cowslopes, of roses, of lilies, of dil, of chamomill, all sodden together. When it is cold put in your erthwormes, stoppe your glass, let it stand xl days in the sunne, then straine it. It will make an excellent oyle against ache, sciatica, goute, etc.”

_Toads That Make Poison Gas_

Among the weirdest of American amphibians are certain of the giant toads of southwestern United States and northern Mexico which, when frightened or in pain, diffuse a deadly gas which will kill objects some distance away.

A very large toad found almost everywhere throughout the Panama Canal Zone can squirt a poison which may permanently blind a man if it hits the eyes. Nobody would bother it except that from its skin is made of the softest and most expensive of all leather.

Most toads have skin covered with warts which are more closely grouped on the sides of the neck than elsewhere. These, together with the paratoid glands situated behind the eyes, secrete a milky, poisonous fluid whenever the animal is molested. The secretion is an acid irritant, causing pain in cuts and producing a bitter, astringent sensation in the mouth.

_Plants That Thrive on Ice-Bloom_

There are plants that grow in ice and snow. This phenomenon—known to botanists as cryovegetation—has been the subject of intensive study at Mt. McKinley National Park in Alaska.

The plants are responsible for the strange phenomenon of ice-bloom. Ice fields at various seasons take strange colors. The plants are very minute members of the almost universal algae family which are among the most primitive forms of life on earth. They are able to extract the nourishment they require from the surface of a glacier as it melts slightly under the glare of the Arctic sun. The phenomenon has been reported by Arctic explorers for many years but until a few years ago very little was known of the responsible microorganisms. They are a striking demonstration of the fact that life has spread to all possible habitats on earth in some form or other, even to fields of solid ice.

While nobody is likely to stake out a few thousand acres of glacier for a farm, an Hungarian botanist, Dr. Ersebet Kol, has made first-hand studies of the conditions under which the minute plant organism could live and multiply, including the acidity of the ice. Concerning the Columbia glacier, one of the largest in the Alaska ice-fields, Dr. Kol reported to the Smithsonian Institution: “When I stepped on the ice, I saw for the first time a phenomenon to be seen only on coastal glaciers. The surface of the ice was covered for miles and miles with light brownish-purple algal vegetation called ice-bloom. This effect is produced by immense quantities of minute plants called Ancyclonema, a characteristic plant of the permanent ice. It can never be found elsewhere, even on permanent snow. It belongs to the green algae first found on the coast glaciers of Greenland. Since that time, the microorganism has been found in several localities in Europe, and I have found it occasionally on the glaciers of the interior but never in sufficient quantities to form the ice-bloom of the coastal glaciers.

“Here I had an opportunity of studying another striking phenomenon of the permanent snow regions of Alaska—colored snow, especially red snow. Above Valdez, around the Thompson Pass, the snowfields glitter with a reddish color in the beginning of August. The snow was red not only on the surface, but also to a depth of several inches and even in one place to a depth of two feet, caused by the presence of millions of tiny plants, Chlamydomonas nivalis. The snow on Thompson Pass looks as though it has been sprinkled with red pepper, differing in this respect from the red of other snowfields, which is usually a light raspberry red.”

_Poison Arrow Frogs_

There is a green frog, about the size of a half dollar, that is one of the most virulently poisonous creatures on earth—but only after it has been roasted alive. It is common at the Smithsonian Institution’s tropical wild life preserve in the Panama Canal Zone. When living it is quite harmless, at least to human beings although some believe it can poison other frogs. When it is roasted over a slow fire, however, a toxin is exuded from its skin which is a potent nerve and respiratory poison. It once was used by the Choco Indians to poison the arrows with which they hunted game and Spaniards.

The poison arrow frog is a delicate creature which is confined to a narrow temperature range and probably never has reached the United States alive. A ground and tree-dwelling animal, it is quite elusive.

A close relative is a brilliant scarlet frog, a denizen of the treetop of the dense Panama rain forest. From its skin also is exuded a virulent poison. One of the two jungle canopy frogs, it is less than an inch long. Its body has deep scarlet both above and below; its feet are black and its thighs are flecked with metallic green on the rear and metallic blue on the front. It is found only on the Atlantic side of the isthmus near the mouth of a small bay where Columbus once landed for fresh water. Outside its narrow range the creature has never been seen in its gorgeous colors. In captivity it probably would die very quickly. Placed in a preservative, it quickly turns to a drab, uniform black.

The animal is a remarkable and peculiar climber. It ascends a tree trunk by a series of short jumps, catching its toes in rough spots on the bark. (Other tree frogs have suction disks on their feet by means of which they can walk up a tree in leisurely fashion.) It makes its way unerringly from the ground to its treetop home, a pool of water in the axil of a bromilead or “tank plant,” a tree of the pineapple family.

_The Seal That Can “Lose” Its Head_

An animal that can pull its head almost completely into its neck has recently been added to the mammal collections of the Smithsonian Institution. This is the Ross seal, one of the rarest of all the seal family in the Antarctic.

A frozen specimen captured by the Navy’s polar expedition in 1956 arrived at the U. S. National Museum in Washington in excellent condition. This seal—about 8 feet long—dwells exclusively on the drifting ice pack of the Ross Sea. So far as is known it never comes on land or on the ice shelf. It apparently feeds almost exclusively on cuttlefish and squid, which are abundant in Antarctic waters. To judge by the nature of its teeth it undoubtedly is not a fish-eater. It is yellowish-green on the underside and blackish-brown on the top, the fur often being marked with pale streaks along the sides.

On the drifting pack it has fearsome enemies—notably the killer whale and the writhing, snake-like sea-leopard, most savage of the seal family—which may account for its relative scarcity. The outstanding peculiarity of the creature, probably unique among mammals, is the thick bloated neck into which the head can be withdrawn. This may be a protective characteristic although it could hardly serve the creature against its fierce enemies. On the other hand, withdrawal of the head may be a comfortable habit in a very cold climate.

_The Delectable Horned Viper_

All along the Nile and the Red Sea coast is found the horned viper which lives buried wormlike in the sand with only its eyes and the upper part of its head visible. Its horns are said to look like barley grains and to entice birds. It is found often in rodent holes. This horned viper is extremely tenacious of life. It has been kept alive in a glass jar, without food, for two years. It can hurl itself forward as much as three feet. A full-grown specimen is about 18 inches long and quite poisonous but Egyptian magicians have been seen eating the animals like stalks of celery.

_Flying Snakes, Frogs and Toads_

There are flying snakes as well as flying frogs and toads. Such reptiles and amphibians should be considered expert parachutists rather than actual flyers.

The tree snakes dendrolaphis and chrysopelea leap from high limbs, stretched out lengthwise and both flatten and broaden the body so that it presents a concave surface. They glide to earth slowly, at an angle to the vertical, and land apparently without injury.

Frogs of some species have enormous webs between the fingers and toes which serve as parachutes. A Brazilian tree frog has been observed to drop from an altitude of 100 feet and land 90 feet away uninjured. Since other frogs of the same size were killed when dropped vertically, parachuting must be considered a distinct trait of this particular species, developed over many generations of life in treetops.

In the course of experiments a South Carolina lizard, frequenter of bushes and fences, landed ten to twelve feet away from the place where it was dropped, at a height of 37 feet, and hopped away unhurt. It took a rigid posture when dropped, limbs outstretched and stomach taut. It fell vertically a third of the distance to the ground and then started to glide. A lizard of another species from the same habit wriggled all the way down.

_Eagles Build Log Cabin Nests_

The white-headed eagle became the national bird of the United States by act of Congress on June 20, 1782. For nearly two centuries it has remained the American symbol of fearlessness and freedom. The same bird—Haleoletus leucocephalus and not the more familiar golden eagle found in the West—had been the supreme totem animal of the Six Nations of the Iroquois from whom many institutions of the new republic indirectly may have been derived.

This eagle still is fairly abundant in the fringes of forest around the Great Lakes, its fishing grounds. Its nest, almost always at the top of a tall sycamore or hickory which is dead or dying, is almost literally a log cabin. The bird sometimes uses sticks six feet long for the outer walls. It grasps large dead branches in its talons, breaks them off by sheer force, and flies away with them. A recently observed nest was nine feet high and six feet in diameter.

_The Predatory Mantid_

Why does the “praying mantid” pray? The prayerlike pose of this near relative of the cockroach is its normal position both for seizing its victims and for defending itself.

For their size mantids are among the most predatory animals in existence. They are also among the least known of the insects. There are more than 1500 species in the world, mostly tropical. Only 19 are known in the United States which is on the northern fringe of their normal habitat. One of the most remarkable features of the mantid is its front legs, which bear sharp spines and fold in a curious hinged fashion enabling the insect to reach forward, seize a fly or some other victim, and bring it to its mouth. This is the explanation for the seeming attitude of prayer.

Mantids feed entirely on other animals, chiefly insects caught alive. Instances of small birds, lizards and mice being eaten have been reported, probably due to mistaken observations. There is no question that mature individuals of several species can handle any caterpillar, grasshopper, cockroach or other large insect that comes within its range. Their appetite is enormous. An adult mantid has been known to eat ten cockroaches in less than three hours. Bees and wasps usually have no terrors for the predators, although occasionally a mantid is stung while trying to catch a wasp and gives evidence of the injury.

Sometimes the mantid’s front legs are held in a posture of sparring, rather than of prayer. More than once the sight of one of these insects “sparring” with an English sparrow or some other small animal has attracted a crowd on a city street and gotten paragraphs in the local newspapers.

The mantid usually waits motionless until its prey comes within reach but sometimes, supposedly when very hungry, it may stalk another insect. Sometimes the victim is touched lightly with the antennae before the front legs flash forward and make the capture.

These insects have developed considerable camouflage. Some tropical species look like flowers, their colors blending with those of foliage. One species varies in color from white to pale pink and has the practise of crouching among certain blossoms, the petals of which its legs and other body parts resemble. Others have arranged themselves on plants so that they look like blue flowers. Presumably bees and other flower-loving insects thus are lured to their doom. A few tropical mantids have developed a superficial resemblance to other insects of the same environment which are distasteful to birds and monkeys. Some closely resemble large ants.

There is a widespread belief that the male always is eaten by the female after mating. Sometimes this happens, but the male never is a willing victim and quite frequently escapes. The eggs are laid in groups of from a dozen to about 400. They are deposited in layers in the midst of a thick frothy liquid which soon hardens and becomes fibrous. For the most part, each species deposits egg masses of a distinctive shape.

On the whole, they probably are beneficial insects because the greater part of their prey consists of species injurious to gardens. The possibility of propagating them for the control of injurious insects, such as Japanese beetles, has been suggested because of their notoriously big appetites. It would, however, be impossible to restrict them to a specific pest. They would continue to eat about every living creature of the right size that came within reach of their claws, including many beneficial species.

_Fireflies as Electricians_

The flashing of a field of fireflies is an expensive show. For two generations one of the ideals of science has been to produce artificially “cold light”—radiation confined entirely to those wavelengths to which the retina of the human eye is sensitive without any energy being wasted in the form of heat or invisible light. Could the ideal be attained with the same expenditure of fuel and power as is required for light production at present the world’s bills for illumination would be decreased enormously.

Actually the firefly has attained this ideal in one direction. It emits only visible light. From this point of view the firefly or any other sort of luminescent animal is very efficient indeed. A good part of the total radiation from any man-made source of light—or for that matter from the sun—is invisible infrared, observable only as heat. Possibly the firefly produces some heat in its light production but it is too little to be measured. It is safe to say that within a tiny fraction, 100% of the radiation produced is in the visible spectrum—most of it shorter wave lengths than those which produce the sensation of blue light. This is by far the highest efficiency known to science.

Chemists can duplicate the process to a certain extent. Consequently a great deal of research has been devoted to the light-emitting mechanism, physical and chemical, of the insects. Firefly luminescence is due to the oxidation—that is, the burning—of a chemical substance, luciferin. This reaction, in turn, depends upon a catalyst known as luciferase. The same phenomenon can be brought out by appropriate mixtures of luciferin, luciferase, and oxygen in a test-tube at the proper temperature.

All these experiments have shown that, considering the amount of oxygen necessary, it is a very wasteful process. It is far less efficient than most means of producing artificial light known to man—one percent compared with the 4.54 percent of the carbon filament; 17.17 percent of the acetylene flame, or 60 percent of the sodium arc light. To illuminate houses or streets with firefly light would be a very expensive procedure indeed.

Dr. N. D. Maluf of Yale University quotes a calculation that “an area of firefly light six feet in diameter on the ceiling of a room nine feet high would give ample illumination for reading or drawing on a table three feet high.” This would hardly interest an illuminating engineer. The light can, however, be used in an emergency. During the Spanish-American War Major General W. C. Gorgas is reputed to have used the light from a bottle of fireflies to perform an emergency operation. The average householder would rebel at the monthly bills.

The actual light from a single firefly is very minute indeed, averaging little more than 25 thousandths of a candle power. The combined courtship efforts of a whole field full of the insects would hardly light a single room enough for sewing or reading. The insect will sometimes glow steadily with a light as low as two hundred-thousandths of candle power intensity.

Among fireflies, flashing is essentially a courtship phenomenon, yet there is no discernible difference between the quality of the light of male and female insects. What actually happens is that the flash of the female in response to the signal of the male is timed almost exactly at a trifle over two seconds. The male is instinctively aware of this time interval, so that he does not become confused with the signals of other males. In a large group of the insects the flashes of the two sexes tend to become synchronized, producing a field of light.

_The Mollusk Vampire of Hell_

Black demon of the realm of everlasting dark is Vampyrotouthis infernalis. Most nightmarish of living animals, this “vampire of hell” has a midnight-black body about two inches long, red-brown round face on a head almost as large as the rest of the body, red eyes an inch in diameter encircled by narrow bands of pinkish-orange, rows of ivory white teeth, ten wriggling, ever-probing tentacles extending from the head. On the sides of the neck are two powerful, flashing lights each of which is a cluster of about 50 tiny phosphorescent nodules. The entire body is covered with hundreds of tiny lights.

Fortunately nobody is likely to meet this horror of an hallucination-damned maniac’s ravings on a lonely road passing a graveyard at night. It is a mollusk, a close relative of the octopus and the squid but belonging to neither family, which lives in abysses of sub-tropical seas all around the world, far below the depths reached by the most penetrating green rays of the sun. Only its relatively small size and restricted habitat prevent it from being the most fearsome, loathsome creature on this planet.

The “vampire” is a living fossil, survivor out of the demonic seas of 200,000,000 years ago which found shelter from the inexorable scythe with which time mows down demons by retreating further and further into the dark. Imprints of quite similar sea animals, probably denizens of warm, shallow waters, have been found in English rocks.

Up to now about a hundred individuals have been taken from the deep sea, mostly by scientific expeditions. Of these, nearly two-thirds have come from the Atlantic off the Florida coast and near Bermuda. There are several in the Smithsonian collections. The fantastically terrible little mollusk was first taken in the Indian Ocean by Dr. Carl Cuhn of the German Valdavia expedition about 75 years ago. Until quite recently all specimens obtained have been in poor condition and there has been considerable difficulty in classifying them. The job has been complicated by the fact that the vampire apparently undergoes a series of metamorphoses which have been mistaken for different species. During the past ten years, however, they have been studied intensively by Dr. Grace Pickford of the Bingham Oceanographic Laboratory of Yale and their fearsome reality has been established beyond question.

Naturally, since the living animal cannot be observed, essentially little is known of its habits and ways of life. Certainly it is a voracious carnivore like all others of its race and preys upon every other creature of the depths in its size range. It seems to be confined exclusively to a depth of about 1,500 meters. This is the level of the sea where, for some reason oceanographers are unable to fathom, the oxygen content of the water is lowest. It goes up immediately both above and below. The vampire, apparently, cannot stand too much oxygen. Its eggs sink to about 2,000 meters where they reach their suspension level. As soon as the little mollusks hatch they rise to their natural habitat.

The vampire has powerful tentacles but its fin muscles indicate that it is a weak swimmer. It probably lurks in the abysmal darkness for its prey to come within reach of the probing tentacles. Even with its enormous eyes and its many lights it hardly can distinguish moving objects very well and presumably is not particular about what living things it eats. Its usual victims probably are fishes and smaller mollusks. It is unlikely that the creature has many natural enemies it need fear. Unlike the octopuses, its nearest relations, it has no ink sac from which to discharge a black cloud around its body for its own concealment.

_Climbing and Flying Frogs_

A family of frogs that climb trees, burrow and are learning to fly are the tree frogs of Mexican tropical forests. Various members of the family are at different stages in their physical adaptation to tree life. They constitute a striking example of evolution at work as a race struggles to shake itself free from one environment and conquer another despite considerable odds.

The ends of the fingers and toes of those frogs are provided with adhesive disks by means of which the animals are able to obtain a firm foothold on relatively smooth surfaces. These disks are used mainly for climbing, or for clinging to foliage and limbs when jumping. One species is both a climber and burrower. It is an extremely timid little creature and a poor climber, but it buries itself deeply in tree mosses. Another species, which seems as much as home on the ground as in the trees, deposits its eggs on the upper surfaces of leaves overhanging the water. The tadpoles, which must return to the water for their metamorphosis into frogs, simply drop off the leaves after they leave the eggs. Perhaps the most peculiar of the family is the marsupial frog, Gastrotheca, all of whose young are sheltered in a pouch on the back of the female. Some of the family lay their eggs in nests of froth attached to leaves.

One remarkable species seems to be developing the ability to fly. Its hind limbs are elongated for jumping and it has been known to leap and alight without injury from a height of 140 feet. When handled it exudes a poisonous, milky fluid which coagulates instantly, sticking to the fingers in a disagreeable way. It has a strong odor, like that of peaches, which causes the inside of the nose to itch. Experiments are described in which this animal was dropped from the top of a high water tower. It immediately spread out its limbs and, instead of dropping vertically, sailed slowly downward and landed uninjured on the ground about 90 feet away. Apparently it was able to get the best of gravity after a drop of about twelve feet. From that point on, there was no apparent acceleration in the speed of descent. A state of equilibrium was reached. Whenever one of these frogs was thrown in the air it invariably managed, after a violent struggle, to establish itself in a balanced position which it could maintain, apparently without effort, while it glided to the ground.

Within certain limits these tree frogs can change their color so that their bodies will blend more perfectly with their surroundings. One of the most widely distributed Mexican species seems to have an exceptional color range. This particular creature also is notable for its elusiveness. It exists in countless numbers, yet an explorer may hunt for weeks without encountering a single one. Such was the experience of the German naturalist, Hans Gadow. While wandering along the edge of the forest he heard what seemed to be the noise of a sawmill in the distance. As he came nearer this sound changed into a roar like that of steam escaping from many boilers, mingled with the sharp and piercing scream of saws. It came from a meadow containing a shallow rainwater pool in which were tens of thousands of large, green tree frogs. Gadow calculated that in this pool, about thirty yards square, and in the immediate neighborhood, were more than 45,000 of the creatures. The water of the pool was covered with their spawn—a minimum of 100,000,000 eggs. The next morning there was not a single frog in sight. The water had evaporated during the night and the eggs were left to be cooked by the sun.

One of the most curious of these creatures is the banana frog, whose habitat often is the upper side of a banana leaf. It is an extremely elusive creature whose color undergoes considerable change without being specifically responsive, so far has been observed, to the intensity of light. Another curious member of the family wraps its eggs in foamy lather and suspends the whole mass between leaves or blades of grass over water in such a manner that the next heavy rain washes the developing eggs or tadpoles into it. It is necessary that the tadpole stage be passed in water. Development of means to bring this about was necessary before the family could conquer a tree environment.

Another little frog spends its entire life in the leaf-formed cup of a bromelia, a plant somewhat similar in appearance to a small century plant, which grows on the branches of trees where its roots get a precarious foothold. During the rainy season this cup becomes filled with water. There the frog lays its eggs, which hatch as pollywogs.

Truly demonic are fantastic horned frogs of Brazil which devour other amphibians and small mammals. The largest of them do not hesitate to defy a human being in the mountain rain forests, their chief habitat. They are six inches long or longer and as broad as long. Some have horns on their eyelids and the tips of their noses. All have enormous mouths, so that a mouse can be swallowed quite easily. When excited they inflate their bodies like balloons and utter bull-like bellows. At other times they are heard to cry like infants.

The horns probably serve no other purpose than to add to the ferocious appearance of the animals. They are just hardened extensions of the skin, entirely too soft to be of any value in combat. All species of horned frogs are rare in collections. They seldom are seen because of their secluded habitat and their clever camouflage. They throw loose dirt over their damp bodies until they become practically invisible.

Rarest of the family are the pigmy horned frogs which have horns on both eyelids and the tip of the nose, as well as a fringe of horns around the eyes. They are beautifully marked animals.

_Mad Dog Cycles_

There may be mad dog cycles. Dogs are much more vicious in June than in the so-called “dog-days” season of July and August.

The tiny poodle and the pekingese share with the big German police dog and the Italian bull rank among the 10 most vicious of domestic canines. These are some of the conclusions reached by Dr. Robert Oleson of the U. S. Public Health Service on the basis of data about dogs in the metropolitan New York area for 27 years.

During this period, Dr. Oleson’s study shows there were two 5-year peaks in rabies, from 1911 to 1915, inclusive, and from 1926 to 1930. During the first period the annual average of bites diagnosed as made by rabies-infected animals was 233, compared with only an average of 78 for the previous three years for which records were available. There followed a period of 10 years during which the number of rabies cases diagnosed in biting dogs averaged only 43 a year. Starting with 1926 the curve leaped up again and in the next five years there was an average of 288 cases a year. Then came another rapid decline.

Apparently the number of rabies cases has no relation to the number of bites. These remained practically stationary at an average of about 3,500 from 1908 to 1926. There was a sudden jump to more than 7,000 cases in 1925, just before the start of the second rabies peak. But since 1930 the number of bites reported has continued to go up, in the face of rigid muzzling restrictions, until it has reached the alarming figure of 20,000. At the same time the number of rabies cases rapidly has gone down.

The same tendency toward the mad dog cycle has been noted in several European countries. It may be due to an inexplicable waxing and waning of the virulency of the rabies virus. During the peak years extraordinary efforts were made to impound all unlicensed dogs, and the decline of the waves may have been due to the lessening of the number of potential rabies carriers by this means.

Contrary to general belief, dogs are getting better tempered rapidly during dog days. The high peak of the year in bites is reached about the middle of June. Then comes a very sharp drop, which continues steadily as colder weather comes on.

No breed of dogs is entirely free from the biting tendency, but some are much more prone to it than others. The mongrel doesn’t rank among the really vicious dogs and pedigree counts for nothing. The 10 breeds, in the order of frequency of their reported bites, are: German police, chow, poodle, Italian bull, fox terrier, crossed chow, airedale, pekingese and crossed German police dog.

_The Amazing Survival of the Opossum_

The opossum, sole survivor in the New World of a primitive and very ancient family, represents an overlooked principle in evolution—survival by endurance.

How this clumsy, persecuted animal has endured through millions of generations in the midst of savage and hungry foes is the subject of a revealing study by Dr. J. D. Black of the University of Kansas.

Dr. Black examined closely the skeletons of 95 opossums in the university museum—all killed in the immediate vicinity. Thirty-nine of them gave evidence of broken bones that had completely healed. One specimen had suffered, and recovered from, breaks of both scapulae, 11 ribs, two broken in three places, and a badly injured spine. Still another gave evidence of having suffered at the same time fractures of the jaw, the scapulae, and nine ribs. Many showed evidence of ribs and scapulae broken in several places. The ability to survive such severe injuries—they would be fatal in any other animal either in themselves or because the crippled condition resulting from them would make a creature an easy prey to its enemies—illustrates the importance of the opossum’s practice of playing dead.

The opossum represents an important stage in the evolution of mammals—that of the marsupials, or pouch bearers. They presumably were quite widely distributed over the earth at one time, before the emergence of the placental type of mammals to which the human race belongs, together with almost all other warm-blooded animals. They may be the ancestors of the placentals or they may represent a different line of development from the ancestral reptiles. In any event, they are considerably nearer the type of those ancient egg-laying reptiles. They are just a step beyond the egg-laying stage.

When the placentals arose the marsupials quickly disappeared from most of the earth. They were not so well adapted for survival in conflict with the more advanced, efficient type of animal. Only in Australia did they find a haven. With a single exception, they were the only mammals there when the continent first was discovered by white men. This has led to the speculation that Australia was cut off from the rest of the world before the placental races were evolved, or before they had attained such efficiency in the ways of life as to enable them to survive. There the marsupials, without competition, were able to survive and differentiate into rich fauna of the continent—of which the kangaroos are considered the most characteristic animals.

The one exception was in North and South America in the person of the lowly opossum. All the meat-eating animals which arose around the creature fed upon it if they could catch it. It was not very efficient in getting away from a pursuer. It developed no effective armor, like the shell of the armadillo or the quills of the porcupine, with which other weak animals managed to survive. It was not even very efficient at hiding. When man arrived on the scene with his bows and his guns, its last havens, the treetops, lost their small measure of security.

All the cards were stacked against the survival of the opossum, but it developed a means of its own to keep a tenacious hold on life while far more efficient creatures—beset with new enemies and changing climates—were forced to give up. The great mammoth herds, lords of the earth for a million years, disappeared. The ferocious saber-tooth tiger and the great cave bear expired by the roadside in the race of evolution. But the poor opossum had discovered the important principle that the meek shall inherit the earth—or, at least, be allowed to live in it. It became the great pain endurer and lived by submitting and gritting its teeth. It didn’t fight nor hide. It merely suffered and learned how to endure suffering. This supreme ability of the opossum to recover from injuries goes a long way toward explaining its survival.

The opossum thus appears to be the prototype of a familiar class of men and women. They are frequently encountered. As children they have almost every conceivable disease. Their adolescence is a continuous succession of broken bones. Their parents despair of raising them. When they come to adult life the story is much the same. They suffer a constant stream of misfortunes, physical and otherwise. Physicians are amazed at their recoveries. And they often survive into the 80s and 90s of life while the healthy, fortunate individuals with whom they started out are left behind in the prime of life—victims of pneumonia, heart disease or accident. When the latter die the news comes as a surprise to their acquaintances who cannot understand how the strong die and the weak survive. They ponder over the paradox that strength is weakness and weakness strength. The ancient opossum might explain that paradox if it had the means to express itself.

_Mammal Prototypes of the “Mermaid”_

The prototypes of the “mermaids” of legend are among the least known of all animals to naturalists because of their underwater habitat and their secretive habits. They are the manatees of the Caribbean region and the dugongs of the Indian Ocean. They constitute the only remaining species of the serenia, or moon creatures, distant relatives of the elephant. Both have a somewhat human facial appearance. They feed standing upright in the water, their flippers held out before them like arms. Sometimes the females hold their calves in these flippers. Seen from a distance, they have a curiously human appearance, which may account for the many reports of mermaids and mermen.

This is especially true of the dugong—a creature of the open sea, with a white, almost hairless body. It is extremely secretive and has almost never been captured alive. When one is washed ashore or caught in a fisher’s net it causes superstitious fear among the natives. The manatees are not so human in appearance and are much better known.

The creatures seldom make their appearance above water in daylight. They prefer to gaze in the moonlight, and this has added to their humanlike appearance which has given rise to the mermaid legends.

One of the few persons to study the animal at close range, O. W. Barrett, an American explorer, tells us the following concerning the manatee:

“The animal still is fairly common in most fresh-water bayous, lagoons and rivers along the east coast of Nicaragua. One of the best-known herds on the Caribbean Coast inhabits the Indio River, just north of Greytown, Nicaragua. Estimates of its number vary from a few score to several hundred. The herd apparently is stationary there and does not increase or decrease to any notable degree from year to year, although the natives take a heavy toll....

“A manatee can remain under water from 20 to 30 minutes when frightened. During the daytime the slightest unusual noise, like rain falling on a tin pail or the spitting of the hunter, is sufficient to keep the whole herd submerged for hours, yet while they are grazing the hunter may go up and slap them on the back unnoticed.

“Families consisting of a bull, a cow, and one or two calves usually ... merge into a herd of from 10 to 50 or more individuals living in a certain stretch of river, concentrating during the day and scattering at night. They generally graze at night, although a few individuals may be seen feeding in broad daylight. The body is held nearly vertical while grazing. The head is held well out of water, while the armlike flippers poke the grass toward the mouth. The noise made by the flapping of the huge upper lip and the crunching of the large teeth can be heard distinctly 200 yards or more away. The sound is much like that of horses grazing in a pasture. Adult manatees appear to average somewhere between 8 and 10 feet in length. Some—old females, presumably—may reach 12 feet.”

A much more seclusive animal is the true “mermaid” of legend—the dugong of the open ocean. Unlike the manatee, it is a creature of the sea and seldom ventures into the fresh-water rivers and lagoons. Few naturalists ever have actually seen one of the creatures. Mr. Barrett’s first acquaintance with the creature came in Mozambique, Portuguese East Africa, when some native fishermen caught in their net what they described as a “white porpoise.” They were terrified and gladly presented their catch to an Italian blacksmith. This man crudely embalmed the animal, placed it in a rough coffin and freighted it to Johannesburg, where he rented a show room and made a fortune exhibiting “the only genuine mermaid—half fish, half human.”

For many years mariners in the Indian Ocean and the Red Sea have told of seeing objects resembling women standing waist high on the surface. Zoologists of the Middle Ages described a “bishop fish” which had been seen standing with outstretched arms, supposedly blessing the waters. In nearly every case, it seems likely, the objects were strange water animals—the dugongs. They have a curious resemblance to human beings, especially naked women, when seen from a distance.

Nearly all mermaid stories have originated in water where dugongs are abundant. Spanish and Portuguese sailors, the first Europeans to encounter the animal, called it the “woman fish.” The creature is best known to Malagasy fishermen of Madagascar who, while they prize its flesh highly, attribute to it human qualities and affinities. After capturing one the fisherman must perform various religious rites and before he is allowed to sell the flesh at a public market he must take an oath that there have been no unnatural relations between himself and his mermaid victim.

The female’s breasts are roughly in about the position of those of women. She has the habit of rising about halfway out of the water and sometimes has been described as holding her baby in her flippers. Little is known of the life history and habits of the dugong. It is a creature of the shallow sea which never has survived long in captivity. It seems to share with the elephant and with man the faculty of shedding tears when it is in trouble or pain. One which was kept for several months in the Colombo zoo in Ceylon constantly was weeping. Malagasy fishermen used to torture the animals in order to collect the tears, which they sold as love charms.

Another extant member of the “mermaid” family is the manatee, found on both sides of the Atlantic in the warm, fresh water rivers of Africa and South America. Although never mistaken for a human, it is accorded considerable superstitious regard. The Kalaboi of Nigeria regard it as a sacred animal and the incarnation of a human soul. If a fisherman kills one, by accident or otherwise, he must undergo an elaborate cleansing ceremony which involves offerings before images of his ancestors and remaining indoors for three days. During this period he is rubbed from head to foot with a yellow pigment by women of his family. While the purgative rites are in progress the women sing at dawn and dusk. On the third day there is a feast on the meat, but a bit must be given to every household in the village to lay upon the shrines of ancestors.

Both manatee and dugong, and formerly the extinct sea cow of Bering Sea, are probably the closest living relatives of the elephant. They have similar brain and heart structure. The molar teeth of the mermaid family are like those of early elephants. The male dugong has tusks. There also is a great extension of the upper lip which overlaps the side of the mouth—a start in the direction of a trunk.

The next nearest relatives of the elephants are the hyraces, or conies, of Africa and Syria, best known in the form of expensive fur coats. They look and act like rabbits. A Hebrew prophet made them symbolic of timidity. Only a taxonomist would suspect these little creatures could claim any kinship to the largest of land mammals.

_Limbless Lizards and Glass Snakes_

A supposedly welcome guest in the underground chambers of leaf cutter ants is the amphisbaena, a nearly limbless lizard about a foot long which looks somewhat like a gigantic earth worm. These creatures, seldom seen, can be found from Brazil north to lower California and there is one isolated species in Florida.

“Those brought to me,” observed the noted British naturalist and explorer of Brazil, Henry Walter Bates, “were generally not much more than a foot in length. They are of cylindrical shape having, properly speaking, no neck, and the blunt tail which is only about an inch in length is of the same shape as the head. This peculiar form, added to their habit of wriggling backwards as well as forwards, has given rise to the fable that they have two heads, one at each extremity. They are extremely sluggish in their motions, and are clothed with scales that have the form of small imbedded plates arranged in rings around the body. The eye is so small as to be scarcely perceptible.

“They live habitually in the subterranean chamber of the Sauba ant; only coming out of their abodes occasionally in the night-time. The natives call the amphisbaena the “mai das Saubas,” or mother of Saubas, and believe it to be poisonous, although it is perfectly harmless. They say the ants treat it with great affection and that if the “snake” be taken away from the nest the ants also will forsake it. I believe, however, that they feed on the saubas, for I once found remains of the ants in the stomach of one of them.

“Their motions are quite peculiar. The undilatable jaws, small eyes and curious plated integument distinguish them from other snakes. These properties evidently have some relation to their residence in the subterranean abodes.”

Closely related is the Florida worm lizard, rose-colored and completely legless and earless. It is about a foot long and looks so much like an earthworm that expert collectors have been fooled. A peculiarity is that it always goes down into a burrow tail first.

The Arizona worm lizard, a somewhat fabulous animal of the same family, is not, so far as is known, represented in any collection. One veteran miner told of dragging “a purple snake with two legs on its neck” from the gravel. A woman claimed to have kept as a pet for three months “a purple snake with its legs where its ears ought to be.”

All these animals are in the same general family as the glass snakes of Europe and the United States. These are long, slender, legless lizards. They are burrowing animals which occasionally are turned up by ploughmen, but they often come to the surface voluntarily at night. Specimens occasionally found in daylight usually are hiding in dark recesses.

Each animal consists of apparently quite separate parts, body and tail. The body is from six inches to a foot long, according to species, and the tail may be twice as long. The animal can disengage its tail by a single twist when caught by that organ. The slightest injury or rough handling causes this tail to fly to pieces. Each piece wriggles energetically, supposedly to attract attention while the lizard itself crawls to safety in its burrow. The body does not break up and does not, as popularly reputed, come back later to gather up fragments of its tail. Instead it grows a new tail, always smaller than the original, from the stump.

_The Only Bug in the Sea_

Only one group of insects has taken to the sea—the small, gray long-legged water striders. Unlike fresh water relatives of the same genus, these have permanently lost their wings. They have no further use for this means of movement in the ocean.

Great numbers have been found floating and swimming in the open sea around Pacific islands. Both nymphs and adults sometimes are blown onto the beaches by strong winds. They are awkward on land, seek shelter in any depression in the sand, and fall easy prey to birds and the multitude of ghost crabs which glide over the sands after dark.

On the surface of shallow water the insects are found in groups of hundreds of thousands. Apparently they feed on plankton which rises to the surface at night. They themselves are not eaten by fish. This is probably due to scent glands which secrete a strong odor which is repellant to the ever hungry vertebrates.

In small embayments are found enormous numbers of one type of water strider, the female of which is less than a twelfth of an inch long. The male is considerably smaller and rides on the back of his mate to ensure that the two will not be separated by wind or tide.

Insects are by far the most abundant of all land animals; the reasons why only one genus has invaded the sea have been the subject of much speculation. On the continents, insects are found in salt water lakes where the saline concentration is much greater than in sea water. Other types live in torrential streams and waterfalls where they get much rougher treatment than would come from wave action. There are two probable reasons for the failure to invade the ocean. One is the fact that no insect ever has been able to live in very deep water. The “bug” race has evolved a special breathing mechanism admirably suited to life on land but rather poorly adapted to life under water. Besides, the seas have been taken over almost completely by the remote relatives of the insects, the crustaceans. These include, besides crabs and shrimps, the superabundant copepods, the “lice of the ocean.” Invaders from the land never have been able to compete with them.

_A Crocodile With Life After Death_

There is an animal that can bite—it might even slash off a man’s arm—after it is dead. Alive it is relatively inoffensive. Being killed makes it positively mad.

Its uncanny ability to bite half an hour or more after its neck has been broken is a major risk for followers of one of the most adventurous of professions—the jungle crocodile hunters. Their story is a saga paralleling that of the Antarctic whalers who first told of Moby Dick. One of the most expert of them is Dr. Fred Medem, Smithsonian collaborator and professor of zoology at the University of Bogota. He has twice been bitten painfully by “dead” reptiles.

The animal is the caiman, smaller than either alligator or crocodile and probably more closely related to the former. Its hide, like that of its two fellow crocodillians, is valuable for leather and during the past few years it has been pursued close to extinction by professional hunters in Colombian and Brazilian jungles and lagoons. Dr. Medem is an eminent zoologist. He doesn’t believe, of course, that any animal that is completely dead can bite off a man’s arm, but he is hard put to explain what he himself has experienced. He thinks that part of the caiman’s nervous system which activates its snout and mouth is somehow disconnected from the rest and does not die at the same time. Thus the dead reptile has no consciousness when it bites. It is a reflex action of one small segment of the nervous system that somehow is not completely dead.

There is only one way to be safe for an indefinite period after the caiman is killed. That is to chop a hole in its neck and run a pointed stick into the medulla oblongata, the reflex action center at the base of the brain. When this is destroyed the ability to bite is lost. One can proceed to skin the animal without fear of losing an arm or a finger. Ordinarily this reptile will not attack a human. It lives on smaller animals—wild and domestic pigs and the pig-like capybaras—that venture into the jungle rivers.

Dr. Medem has recently discovered a curious new sub-species of caimans confined, so far as known, to the upper reaches of the Apaporis river, a tributary of the Amazon. It is much more crocodile-like in appearance than the rest of the family, with a very long, narrow snout. The others have broad, flat snouts. It retains prominent bony ridges over its eyes—one of the most striking characteristics that distinguish the caimans from both crocodiles and alligators.

A much more dangerous animal is the Orinoco crocodile, a large reptile which lives only in the Orinoco and its tributaries and has a taste for human flesh. The creature is especially dangerous to bathers and to women doing their washing in the rivers. This is one of the two species of these dreaded reptiles known in South America. The other is a smaller, less aggressive creature of seashore rivers and lagoons. The inland species now is quite close to extermination. Until recently it was pursued by both German and French companies of professional crocodile hunters. Now they have given up because the profits have become too small for the risk.