Chapter VI: Part 6

Among the more reliable bird flight speed measurements are those of herons, hawks, horned larks, ravens and shrikes. Rates range from 22 to 28 miles an hour. Flight in all these cases was normal and unhurried. Other speeds reported by the Smithsonian are: crows, 31 to 45 miles an hour; starlings, 38 to 49 miles; geese, 42 to 55 miles; ducks, 44 to 59 miles; falcons, 40 to 48 miles.

When frightened, most birds probably can nearly double their normal rate, but they cannot keep it up very long. When cruising about in search for food they fly so as not to waste their strength. This is particularly true on the great annual migrations.

Considering ten hours as a fair day’s flying time over land, the measured speeds would carry crows from 310 to 450 miles between sunrise and sunset and ducks and geese from 420 to 590 miles. Considering that they fly in straight lines, this means that they make very good time from point to point. It is highly probable, however, that most migrating birds proceed in a leisurely manner and that after a flight of a few hours they pause to feed and rest.

_The Remarkable Instincts of the Silk Worm_

The silk worm’s brain has an instinct center contained in a speck of nerve cells with a mass of less than a millionth of an ounce. This center is a microscopic so-called “mushroom body”, found in both sides, or hemispheres, of the brain. The discovery, with possible far-reaching philosophical implications, came out of some of the most delicate conceivable microsurgery in which the area was destroyed almost cell by cell by means of an invisibly fine electric needle.

Doctors Carol Williams and William Van der Kloot of Harvard have made minute studies of an American silk worm, the cecropia (common along the Atlantic coast), which spins as strong and delicate threads as the Japanese or Italian domesticated silk worms. The cocoon is a marvel of apparent ingenuity, made of a single thread almost a mile long. It is made in three layers, roughly after the design of a thermos bottle. The outer layer is a tightly woven, waterproof silk bag. Inside this is a layer of loosely spun material which serves as an insulating layer. The third layer, woven around the body of the worm itself, is a bag of exceedingly fine, soft silk. Through each layer a “hatchway” is provided directly in front of the creature’s head. These must be placed one in front of the other with mathematical exactitude. Through them the self imprisoned animal must escape when the time comes, and the slightest error probably would make it a prisoner forever in a coffin of its own creation.

Inside the cocoon the worm remains, adequately protected from cold and damp, for nine months. It emerges as a winged moth, whose sole function in life apparently is to lay eggs to produce more silkworms.

Spinning such a cocoon with its three quite different layers requires extreme precision of movement. Nature has not allowed for any possible variations. Yet the masterpiece obviously is not the result of any thinking, education or practice. The little worm’s life span, for one thing, would not allow for any training. Every movement must be instinctive and presumably unconscious, directed by the same part of the nervous system into whose structure the pattern has been built by nature.

The house building must start at precisely the right time. Until that time, according to the Harvard physiologists, the responsible area of the brain is held in restraint by a hormone secreted from two tiny glands in the head. At the foreordained instant this inhibiting secretion ceases and the mushroom body can go into action. The spinning can be started at any time, however, by destroying the glands.

Williams and Van der Kloot tried effects of two gasses, carbon dioxide and carbon monoxide. Both acted as potent brain depressants, but in quite different ways. The first eliminated the spinning behavior entirely and permanently. The worms wandered about aimlessly, apparently trying in vain to remember what some overwhelming internal drive was pushing them to do. The automobile exhaust gas, carbon monoxide, fatal to humans but without any serious lasting effects on invertebrates because of the lack of the red cells in the blood with which it combines in higher animals, caused them to spin a worthless and meaningless flat layer of silk as long as the effect continued. When this ended the worm started to spin what remained of the mile-long thread in the customary pattern, starting from the point it normally would have reached had it not been gassed.

The biologists then resorted to their unbelievably delicate surgery. They proceeded to destroy the silk worm brain a few score cells at a time. The brain contains hundreds of thousands of cells. The destruction had no effect on the spinning behavior until they reached the mushroom body. When a few cells of this area were killed by the electric current the worm no longer could spin a cocoon but continued to wind and weave its silken thread into three flat sheets, corresponding to the three normal capsules. The weaving continued with the destruction of a few more cells, but only in a single sheet. When a few more were destroyed the entire cocoon-making behavior came to an end.

Thus, Doctors Williams and Van der Kloot concluded, they had located a physical unit of behavior. Within it was capsuled the whole “memory” of the silk worm race with respect to spinning. More than a century ago this mushroom body was discovered by the French physiologist Dujardin, who called it the “seat of instinct.” At that time this was only a wild speculation on his part, without any supporting facts whatsoever.

The instinct center is found in the brains of all insects in whom group instinctive behavior has manifestation. In the honeybee worker, intellectual giant of the insect world, it reaches its greatest size. In drones and queens, who do not display much behavior of any sort, the area of the brain is quite small.

_The Strange World of the Sea_

Under the tossing surface of southern seas is an inferno-like realm of everlasting darkness, inhabited by multitudes of strange animals which exist almost altogether by the laws of beak and fang. Some of them are grotesque beyond the reaches of a nightmare.

Countless generations ago their ancestors, driven by hunger and competition, abandoned the familiar sun-lit world for the perpetual night of the abysmal depths. Then with each family, it was a case of survival of the fittest and variation of form and structure to fit the environment.

Here is the stark struggle for survival with the mask of sunlight, green fields and flowers discarded. It is not different in kind but in degree from the struggle that goes on continually between living things at the surface of the ocean and on the land. Down there all must eat flesh. There is no plant life intermediary between beast and beast. Plants cannot grow below the light line of the sea depths.

Out of this fierce war for existence have come creatures mostly conspicuous for their defensive and offensive equipment. Some of the fish seem to have become little more than enormous mouths with rows of long, razor-like teeth with which they seize and kill. The bodies attached to these mouths are small and slender. Such a creature is mostly head and the head is mostly mouth. Nearly all the fish carry light organs of some kind near the mouth with which other animals are probably attracted within grabbing distance.

One of the largest collections of deep sea animals was assembled a few years ago near the Puerto Rico Deep, the deepest part of the Atlantic Ocean, by a Smithsonian Institution expedition led by Dr. Paul Bartsch. This collection constituted a fair representation of the sea life at depths of about 3200 feet, nearly 2500 feet below the farthest reaches of the sun’s rays. There were shrimps with long, sharp claws which fold up after the fashion of an old-fashioned straight razor. Any small creature which came within striking distance of such a razor probably would be an immediate victim. There were strange mollusks with shells like corkscrews and eels like darning needles with long, sharp beaks.

Among the most fantastic was the needle-fish. It jaws are prolonged into extraordinarily slender points, like fine needles, so that the head is nearly as long as the rest of the body—that is, about six inches. This fish was lured to the net by an electric light.

A group of flat fish, or flounders, was obtained, all of which have two eyes on one side of the head and none on the other. Instead of right eye and left eye there is upper eye and lower eye.

Other strange forms in the collection:

The hunchback fish, a creature whose strangely shaped body suggests its name.

The lance fish with long, backward-reaching spines suggestive of lances just behind the eyes.

The forceps fish, one of the most aberrant of all with its greatly extended, forceps-like jaws. There is apparently but a single genus and species in existence.

The family of snout fish with snouts almost as long as the rest of the body. At the end of the snout is a mouth.

Another strange creature taken out of the depths by this expedition was Johnsonia eriomma—the “big eye fish.” Each of its two eyes is about a fifth as long as the diameter of its body. A man’s eye, in the same ratio, would be about a foot long and protrude about eight inches from its socket. It also has two false eyes on its sides, near the tail. They are of the same size and approximately the same pattern as the true eyes. They probably are indistinguishable from them by other fish. They are, however, only color spots and have no visual function. They constitute a feature hitherto unknown in the fish world. The purpose of the false eyes is unknown, unless they are intended to deceive the creature’s enemies. Since it is a slow-moving fish, these color spots probably create the illusion of fast movement which would fool a predatory animal of the abysses.

This fish is the second of its family ever found in the western world. The other was discovered a half century ago the genus have been found in Asiatic waters.

This eye-fish was obtained from a depth of between 150 and 300 fathoms—just about on the borderline of eternal darkness where eyes would be of no use. Fish of the depths have evolved in two directions—toward enormous eyes and toward greatly diminished ones. The first represents a struggle to see in the strange dusk. The second trend denotes giving up of a futile struggle on the part of the race. This trend is noteworthy among fish of the greater depths.

Another strange denizen of the depths is Peristedion bartschi, named in honor of Dr. Bartsch. It is an armored gurnard, of the family sometimes known as “sea robins.” The shell-growing tendency among fish is largely confined to certain fresh-water catfish of South America. This creature obviously is a bottom dweller. Its entire body is covered with spiny plates which probably would make it safe from any enemy. Each plate bears a very sharp spine, about a quarter inch long. There are nearly a hundred of these on the body. This fish would probably be about the most unappetizing morsel any predatory animal ever swallowed. It is bright red.

Still another species obtained by the expedition was one of the “lantern-fish” group. These are small, minnow-like creatures who live only in the open ocean. While most fish either remain near shore or have at least an association with the bottom these are found only in deep water far from land, and never near the sea floor. Most of the millions of them in the sea doubtless live and die without any realization that there is either bottom or shore. All have rows of luminous spots along their sides which probably serve as recognition marks.

_The Cannibal Birds of the Pacific_

Hordes of big black birds, about the nearest creatures imaginable to the harpies of Greek mythology, nest on desert-like South Pacific Islands. These are the vulture-like frigate birds—the Polynesian “iwas” or “thieves”—which are found by thousands in branches of the most prominent shrubs, the eight-foot-high, white flowering scaevola bushes. They are truly creatures of evil.

They carry in their feathers as parasites creatures nearly as malevolent in appearance as themselves—louse flies which look like giant, flattened black house flies. When these are shaken off they sometimes fly to small black automobiles which they mistake for their hosts.

The nests of the frigate birds are coarse, soil-cemented affairs constructed haphazardly of twigs and driftwood. During showers, the cement of this filthy building material dissolves away, allowing eggs to fall to the ground. Nesting material evidently is rare and highly prized, giving rise to theft. A bird in flight occasionally filches a loose piece from a carelessly guarded nest. The iwa will stoop to murder and cannibalism, flying off with an egg or newly hatched young to eat on the wing. There usually is one egg to a nest, entirely white and a little larger than a chicken egg.

Both sexes take turns sitting on the egg and later brooding the growing chicks. This is necessary not only to incubate the egg and keep the chick warm in cool weather, but also as protection against too intense sunshine. At the incubation time the males are resplendent with blood red, semi-transparent throat pouches blown out like balloons. These extend forward to the beak and downward to hide the breast. The color is due to innumerable blood-filled capillaries in the tissues of the pouch.

Not far from the rookeries of the iwas are those of the stupid, red-footed boobies, or gannets. The name booby is from the Spanish word “bobo”, meaning “idiot”. At times the rookeries of the aggressive marauders and the boob-victims overlap at the edges.

The frigate birds, according to a report of the Pacific Science Board, “escort the stupid, spoon-billed gannets out to feed on schools of squid and small fish. When the gannets get craws full and set sail for home to feed their young, the cruel, curve-billed iwas dive screaming after them, seize them by the tails, and sling the food out of the mouths of the smaller birds. This the iwas scoop up on the wing. This goes on from dawn to dusk. The war cries of the frigates and the plaintive screams of the fleeing gannets quiver down the trade winds like the wailings of lost souls.”

It is commonly reported that frigate birds, lacking webbed feet, never land on the surface of the water because they cannot take off again. This is not true; small flocks are frequently seen landing playfully on the Canton island lagoon, floating, and rising again seemingly without any effort whatsoever.

“The birds nesting in the scaevola,” says the report, “are tame or, depending on the point of view, too innocent or stupid to fly from their nests when approached. The explanation for this habit is their nesting from time immemorial in areas where no predatory animals, two or four legged, ever have existed. (This, by the way, is a notable characteristic of bird life in the Antarctic. The notorious skuas, with whom even the frigates could hardly compare for blood-thirstiness, will not even bother to move when men pass through a flock of them on the ice.) Tame birds were not killed off but lived to reproduce their kind. Now, unfortunately, Pacific islanders employed as laborers, occasionally club the nesting birds at night preparatory to a feast. Such vandalism and resulting pandemonium in the rookeries should be stopped by legislation.”

The ancestors of these and other kinds of sea birds have inhabited the islands during the nesting seasons for milleniums, catching fish and other sea life as food for themselves and their nestlings.

_Eagles as Indian Pets_

The proud eagle was once kept as a “domestic animal.” Memories of this practice have been obtained from the Shoshoni Indians of the Nevada desert. As recently as fifty years ago individual Indians owned eagle aeries in the mountains. These constituted about the only private property recognized by the tribe and rights were zealously maintained.

Expert climbers who scaled the cliffs took the young eagles from their nests. They were subsequently reared in cages or tied to rocks. The purpose was to harvest their feathers for arrows, decoration, or magical rites. The birds were fed pocket gophers and young groundhogs.

When the birds were full grown the feathers were plucked. Then the captives were taken to the top of a cliff and released.

_The Giant Insects of the Carolines_

Giant walking sticks seven to nine inches long, titan spiders that walk on water, little black crickets that dive and swim long distances under water are some of nature’s curiosities on mountainous, jungle-covered Kusaie, easternmost of the Caroline Islands.

Especially unusual are the winged-blue-and-green walking sticks with their fantastic hand-over-hand way of walking. Among the largest of all insects is a walking stick found on the nearby island of Truk. It is reddish-brown and wingless with a body nine inches long. The huge spider’s usual abode is the foliage of long grasses overhanging jungle streams. There it lies in wait for the insects which are its usual prey. When alarmed the big spider drops off the grass into the water and starts running swiftly over the surface. It is provided with “water shoes,” bristle arrangements on its feet. Probably it does not even get its feet wet.

The submarine crickets are little black insects about an inch long which live on damp basalt rocks along the sides of, and in, the streams. They are almost invisible in the dim jungle light but make themselves known by their continuous chirping. When frightened they make long, high dives from the rocks and swim for undetermined distances a few inches under water, where they are invisible.

By far the most fantastic spectacle found on Kusaie is that of the ghostly light which marks the banks of rivers. It is due to some species of ground-growing fungus. A Smithsonian party once was overtaken by darkness high in the mountains where no trails could be followed through the dank jungle. They started wading down a stream which, they knew, eventually must lead to the lowlands and the coast. They waded, sometimes neck deep, in a tunnel of overhanging branches through whose thick foliage no light could penetrate. But always, glowing on both sides of them, were the lines of luminous fungi.

_The Valley Where Dusk is Death_

A belt of poison night where death strikes with the dusk extends down the western slope of the Peruvian Andes. This death belt, first reported by a Spanish physician in 1630, consists of a few narrow valleys at an elevation of from 3,000 to 8,000 feet in an arid, very desolate and sparsely inhabited country. Nearly everyone who spends a night there is afflicted a few days later by a severe anemia which often proves fatal. This is the “verruga” disease. The red blood cell count drops very rapidly. It is not known whether the cells actually are destroyed by the disease, or whether it inhibits the forming of new ones from the bone marrow. The effect in either case is the same. The blood loses its capacity to carry oxygen and the victim slowly smothers.

The malady is known as Carrión’s disease. In 1885 a Peruvian medical student named Carrión inoculated himself with it to prove its identity. He succeeded in showing the cause, at the cost of his own life. He had been inspired to the foolhardy act by extreme patriotism. The Chile-Peru war was just over. Most work on the disease had been done by Chileans. Carión desired that the credit for medical research should come back to Peru.

If one recovers from the anemia a second stage of the malady sets in. The body is covered with wart-like growths, presumably due to some alteration in the blood supply to the skin. One attack gives immunity for life, but the death rate during the first stage is very high.

During daylight the death belt is perfectly safe. This has long been recognized by natives who travel through it freely between sunrise and sunset. The only permanent inhabitants of the region are persons who have recovered from the disease. The borders are sharply defined within a few yards of altitude.

For some years it has been recognized that the infection comes from the bite of a single species of sand fly—a vicious pest smaller than a mosquito. Protection is afforded only by special screens. Ordinary mosquito netting is worthless. The death belt is a place of bright sunshine nearly every day. The insects cannot endure light. They remain secluded and it is difficult to secure specimens, even when the hiding places are known. As soon as darkness comes they emerge in enormous numbers.

Harvard entomologists who investigated the death belt a few years ago spent the hours between sunset and sunrise in a specially screened railroad car. A few moments outside might have proved fatal.

Due to some delicate balance of nature this sand fly seems to be confined almost exclusively to this locality. It is credited with causing about 7,000 deaths in the decade before the last war.

_Enigma of Evolution: the Snake_

Snakes once had legs. There is evidence in their anatomy that they are descended from four-legged land animals. This evidence is found especially in certain bones near the base of the tail of one of the largest of living snakes, the python, which is the most primitive of the order and presumably nearest to the hypothetical ancestor.

Although the snake remains an enigma of evolution, there is no doubt that it got rid of its legs because they were a distinct hindrance to its peculiar ways of life.

The serpent is not very ancient, as animal types go. Evidently it first appeared in the Cretaceous geological period, about 100,000,000 years ago, when the great dinosaurs were the earth’s dominant animals. There are, however, no unquestioned fossils of snakes from the dinosaur days. The first snake-like creature known is represented by fossils from the Eocene, or “dawn”, age in North America. This was quite lizard-like in bone structure. It lived about sixty million years ago, when mammals were developing on earth. Rocks in Germany, laid down about twenty million years later, yield fossils of true snakes of the generalized viper type. Sometime later come fossils of snake giants from Egypt. Some of these probably were sixty feet long. But all these were real snakes, with no traces of external limbs. The ancestor seems lost forever because snake skeletons are brittle and delicate and do not easily fossilize.

Having discarded legs, serpents evolved means of locomotion suitable to their ways of life. This has sometimes been described as “walking on the ribs.” It requires a highly intricate coordination of ribs and muscles and can be compared best to rowing a boat.

“The life of a serpent,” according to Dr. Alfred Leutscher of the British Museum of Natural History, “is a matter of adjustments for what it has lost. It cannot masticate its food so it swallows it whole. It can put a healthy human appetite to shame yet it can, if forced to do so, starve for more than a year. Limbs are missing, so it walks on its ribs, swims and grips with its tail, and climbs with its scales. The outer skin does not grow, so from time to time it is peeled off neatly, even to the scales over the eyes. Taste is poor, but this is compensated for by a strong sense of smell, in which the harmless tongue assists by catching the smell particles from the air. It is proverbially deaf, but may receive ample warning of danger from vibrations through solid objects, which reach its sensitive skin more swiftly than sound can travel through air.”

_The Fastest Growth on Earth_

In the beginning was vestureless life. It was the capacity for self perpetuation and growth in nature, the property of a single complex chemical mixture—protoplasm.

This protoplasm may have come here from another star, a single grain of cosmic dust blown out of the infinite. It may have been mixed by chance in the warm seas of the earth at the beginning of time. It may have been put together according to the design of some cosmic intelligence. It tended to segregate into billions of trillions of infinitesimally minute particles, each sufficient unto itself. The particles were purposeless, voracious, irresistible and immortal. They threatened to devour space and time and all that was in them.

A cell culture of elemental, inchoate life stuff whose original substance increased theoretically 10,000,000,000,000,000,000-fold in forty weeks has been described by Dr. Phillip R. White of the Rockefeller Institute. In his experiments he started with a pellet about the size of a grain of mustard seed cut from a wart-like excrescence on a tobacco plant. He watched it multiply until, arithmetically speaking, if no part had been discarded it would have been an unorganized, purposeless monster spheroid of life 600,000,000 miles in diameter, comparable in size to the whole solar system inside the orbit of Pluto.

It had twelve weeks to complete its first year. At the same rate of growth it then would have been a lusty infant the size of 400,000 solar systems. In a few more weeks it could have swallowed the whole Milky Way galaxy. By the end of its second year it would have filled all the space in known creation, consumed the substance of all the galaxies, and perished of starvation as it bulged outward into the emptiness of infinity.

Such a nightmare actually happened, in reverse. Dr. White had to do everything in a few test tubes, but he was able to witness such a phenomenon of growth as man had not hitherto imagined. First he placed his pellet in a special nutrient solution. It began to expand by the continuous process of splitting in two. Two cells become four, four eight, and so on infinitely. After about two weeks Dr. White cut away a few pellets from the original mass and discarded the rest. These were placed in new nutrient solutions. Every two weeks the experimenter would discard the bulk of each mass which had accumulated and start new cultures with the few pellets which he saved. Each culture increased in size about fifty percent a day. At the end of forty weeks he was left with something not much bigger than he had at the start, but the actual original pellet constituted only about a ten-quintillionth of the final mass.

He happened to have found in the tobacco excrescences an undifferentiated kind of life. The cells had no specialized function. In the actual plant they were kept in order by the rest of the plant cell community, which has no use for cells with no job to do. Once in the nutrient solution, however, they were free of all inhibiting influences. They were not, and never became, wood cells, bark cells, pith cells, leaf cells or any of the other numerous, specialized kinds of cells which make up the plant world. They were something very close to the primaeval plant cells from which, in the course of a couple of billion years, all the others have been derived. Very early these unit structures of life learned that they must stick together and do specialized jobs for each other under the actual conditions of nature. Out of these combinations of specialists has arisen all the magnificent structure of the living world.

But the experimental cells at the Rockefeller Institution had nothing to do except eat and multiply. Each of them was potentially immortal. It did not die but renewed its youth when it had reached its growth by becoming two baby cells. That is how life might have developed from the beginning except for the fact that a cell must eat to live and ordinarily does not have any accommodating scientist to feed it.

_Birds That Duel_

Birds that hold fencing tournaments are the big-billed toucans of Barro Colorado Island, the Smithsonian Institution’s tropical preserve in Gatun Lake, Panama Canal Zone.

They fence with their formidable beaks but seem careful not to hurt one another. One scientist who studied Barro Colorado’s bird life described the birds as follows: “I saw fourteen toucans scattered about in a big leafless tree in the center of the jungle. Two appeared to be fencing. They stood in one spot and fenced with their bills for a half minute or so, rested, and were at it again. Presently they flew off into the forest and then I noticed two others that had now begun to fence. Then one of these flew away, and the remaining one picked a new opponent and fell to fencing again.... They did not move about much while fencing, although sometimes one climbed above the other as though to gain an advantage. They fenced against each other’s beaks and never seemed to strike at the body. There was a fairly rapid give and take...the bills clattering loudly against each other.”

These fencing toucans are among the more conspicuous birds of the island, particularly because of their call—a shrill, froglike “cree,” which is repeated over and over again and can be heard half a mile away. The call is most frequent in the morning and late in the afternoon, but it stops abruptly at sunset.

_Brakes on Plant Life_

There is a “brake” on plant development—perhaps one of nature’s most fundamental controls over surging life. It is a relatively narrow band of light on the edge of the invisible infrared in the solar spectrum. Plant life, and through plants all life, is tied intimately to certain solar wave bands. It has long been recognized that the cornerstone of all life on earth is the process of photosynthesis by which plants, through energy provided by sunlight, are able to synthesize carbohydrates from water and carbon dioxide taken from the air. Animals eat these carbohydrates, the basic food. Other animals eat the carbohydrate eaters, and thus the chain extends from the simplest organisms to man.

But without some other process the carbohydrates might be a formless mass. The second process is that which shapes a plant and controls development of stems, leaves, and blossoms. This may be a light effect second in importance only to photosynthesis itself. It requires very little solar energy. Smithsonian Institution experiments have demonstrated that the control is exercised by red light with a maximum of efficiency at wavelengths around 660 millimicrons—or millionths of millimeters. It has been demonstrated, however, that this formative action can be blocked effectively by irradiation with wavelengths in the far red. The greatest effect is at wavelengths between 710 and 730 millimicrons.

The “brake” is not applied immediately. The maximum efficiency of the far red energy occurs a little more than an hour after the plant is exposed to the formative wavelengths. The implication is that the action interferes with the development process by acting on some product the formation of which is initiated by the shorter red wavelengths. The experiments have been carried out with seedlings of beans. In other experiments it has been found that damage to plants from X-ray exposure—insofar as this results in breaking the bundles of genes, or units of heredity—can be increased from 30 to 50 percent by previous exposure to about the same wave band of far red light that reverses the formative process. On the other hand, the increase in damage is nullified if the X-ray exposure is followed by exposure to the red wave band.

Breaking of the chromosomes, or strings of genes, is one of the first evidences of damage to living organisms by exposure to ionizing radiation. This breaking is responsible for some of the adverse hereditary effects concerning which there has been a great deal of discussion because of possible effects of the atomic bomb fall-out.

The experiments were carried out with pollen of flowers and root tips of beans where results are relatively easy to determine.

_Snails Are the Flowers of the Sea_

There are more than 80,000 kinds of snails in the world. They swim, jump, crawl, burrow, live at the bottom of the sea and in the tops of trees. They range in size from the horse conch of Florida, two feet long, to animals hardly the size of a grain of sugar. About half of all species live in the seas.

Most are bottom dwellers, unable to swim, but several spend their lives on the surface. One, the purple janthina, floats upside down on a raft of air bubbles trapped in a special kind of mucous which it secretes. Others live permanently attached to sea weeds. Most abundant of the sea snails probably are the pterepods, or sea butterflies, which live several feet below the surface in daylight but come to the top in countless hordes at night. In some places the sea bottom is littered many feet deep with their shells, of which there is almost constant rain as the animals die.

Loveliest flowers of the sea are the nudibranchs. Seldom has nature produced in either plants or animals such elaborate combinations of brilliant colors and decorative appendages as in the bodies of these shell-less ocean snails. Although there are more than 2,000 species, they are among the least known of all sea creatures. One reason for this is that most of them are quite small, ranging from a fourth to half an inch in length. Their coloring hardly can be appreciated except under some magnification.

Nowhere are they very abundant. Their habitats vary from close inshore to deep water, but they are most likely to be seen in pools left among shore rocks by receding tides. Their extremely elaborate color patterns may be protective, to some extent. It is known that certain species have the ability to change colors in response to changes in their environment. They become bright red, for example, when living in association with a red sponge. Even more decorative than the color patterns are the appendages, extensions of the skin and sometimes of the digestive tract, which take the forms of delicately modelled, almost microscopic plants.

All these nudibranchs are flesh-eating creatures feeding chiefly on sea anemones found on the sea bottom. Most of the anemones are equipped with thousands of so-called nematocysts or stinging organs. These are microscopic, ball-shaped structures filled with a virulent poison. The same mechanism is best known in sea nettles. As soon as a nematocyst is exposed to any tension it explodes, releasing this poison.

The little sea snails have evolved the ability to swallow the poison balls without exploding them. They pass into the digestive tract, but are not digested. In some way the nematocysts find their way through certain of the appendages growing out of the digestive organs to the outside of the body. There they are retained, and serve the sea snail in the same way they served the sea anemone. The little creature becomes quite dangerous to any of its natural enemies.

Among the most enthusiastic nudibranch collectors is the Emperor of Japan, who has discovered and described several new species. Some of his publications about them have been illustrated by leading Japanese artists and show the unearthly beauty of the creatures to the best advantage.

_The Brutal South Pole Birds_

The southernmost birds on earth—the only higher animal except man and his dogs that go close to the South Pole—are the Antarctic skuas. They are fierce, brutal little killers. Dwellers in the earth’s most inhospitable habitat, they have been able to survive largely because of their extreme rapaciousness.

All other Antarctic birds, such as the penguins, stay close to the shore of the desolate continent. The skua has been seen at least 300 miles inland, and occasionally may fly across the pole itself.

These birds arrive on the coast of Antarctica about the middle of October, the beginning of the southern summer, after spending the winter north of the circle. Their arrival is timed to coincide with the egg-laying of the Adelie penguins. The skua’s chief food consists of penguin eggs and chicks which it devours by the hundreds. Scores of half-eaten, trampled bodies of young penguins always can be found during the hatching season near the sites of penguin rookeries. The skua is hardly a match for the parent birds but is expert in separating chicks from the brood and killing them when they have no protection. It is a creature of relatively enormous strength and endurance and flies long distances carrying chunks of meat bigger than itself. It also is an extremely noisy, quarrelsome creature—an outstanding example of the philosophy of every individual for itself. There is no brooding of chicks nor protecting them from the elements. The parents hardly bother to feed them.

Little skuas, it is reported, come out of the eggs fighting. Usually there are two eggs to a nest. One chick probably is a trifle weaker than the other. In a short time it is driven from the nest, killed and eaten by its rapacious brother or sister. It may even become the prey of its own hungry parents. Skuas also have the habit of eating their own eggs. This keeps the population within the limits of the food supply.

_Silk-Bearded Clams_

Jason’s golden fleece may have been woven from the beard of a silk-bearded clam. The same sort of cloth, in fact, still is produced on a small scale in Italy, chiefly for the tourist trade. A silk glove of modern manufacture now is in the Smithsonian collections.

The clam is a giant Mediterranean species, the pinna marina. Its shell reaches a maximum length of about three feet, but the average is less than half this. From a gland in its “foot” it secretes milk-like strands with which it attaches itself to the sea bottom. These strands are as much as a foot long.

The silk is of exceptionally fine quality—at least it was so regarded by the Arabs who maintained centers for manufacture of the cloth in Spain, Italy and North Africa. Says one Arab author: “At a certain time of the year an animal comes forth from the sea and rubs itself on the stones of the seashore. A down soft as silk with a golden color falls off it. It is fine and small and garments are woven from it which take on different colors during the day. The Umayyad kings (of Spain) used to put restrictions upon it so that it was only exported secretly. The price of a garment is more than 100 dinars, on account of its fineness and beauty.”

The value of a dinar—the gold coin of the Moslem world—is difficult to calculate in any present coinage, but it was at least the equivalent of a dollar.

Says another Arab writer: “I have seen how it is gathered. Divers dive into the sea and bring out tubers like onions with a kind of neck which has hairs on the upper part. The tubers like onions burst and let forth hairs which are combed and become like wool. They spin it and make a woof of it so as to pass a warp of silk through it. The most magnificent royal garments of Tunis are made of it.”

Gigantic clams, nearly five feet long and weighing more than 400 pounds, who raise crops of microscopic plants for their own sustenance are among nature’s fantasies found on Australia’s Great Barrier Reef. These molluscan titans have formed a curious partnership with the zooxanthellae, a family of microscopic algae. The plants live as parasites in the blood cells of the inner lobe of the clam’s mantle. Upon this mantle is a lens-like structure which looks like an eye. These mollusks, however, are blind as any other clams and the eye-like protuberances, it has been determined, are only windows by which light is admitted to the parasitic algae within the blood cells. The surplus of algae is carried by the blood stream to the clam’s digestive organs where it serves as food.

Another giant clam, the tridacna of East Indian seas, may weigh up to 600 pounds. The monsters constitute a peril for divers who unwittingly step inside the open valves. These snap shut, imprisoning the diver’s foot and, unless he can get help, he is held in the trap and drowned.

_Pearls Grow in Brooks_

Excellent pearls occur occasionally in fresh water clams. A pearl of perfect form and pure color was found in such a clam taken from a brook near Paterson, New Jersey, in 1857. It sold at Tiffany’s for $1,000 and shortly afterwards was resold in Paris for $2,200. This started pearl hunts in brooks all over the country.

On the arrival of Europeans in Florida, Louisiana and Virginia, fabulous legends were circulated about the enormous treasures to be obtained by plundering Indian graves. A contemporary chronicler of the audacious DeSoto expedition, reported that the conquistadore got 350 pounds of fine pearls at the Creek town of Cofitachique on the Savannah River.

A member of the first Virginia colony “gathered together from among the savage people about five thousande; of which number he chose so many as mayd a fayre chain; which for their likenesse and uniformitie in roundnesse, orietnesse and pidenesse, of many excellente colours with equalities in greatnesse were verie fayre and rare.”

The supply, however, was quite limited. Indian pearls were the subject of a special study by the late Dr. William H. Holmes. “The majority of those obtained,” he reported, “were ruined as jewels by the heat employed in opening the shellfish from which they were abstracted. Many of the larger specimens probably were not real pearls but polished beads cut from the nacre of sea shells and quite worthless as gems. It has been found that the real pearls were obtained from bivalve shells—from the oyster along the sea shore and in tidewater inlets and from the mussel on the shores of lakes and rivers.

“But the very general use of pearls by the pre-Columbian natives is amply attested. More than 60,000, nearly two pecks, were obtained, drilled and undrilled, from a single burial mound near Madisonville, Ohio.”

_Grasshopper-Infested Glaciers_

Among America’s natural curiosities are “grasshopper glaciers.” These are great masses of glacial ice containing layers of imbedded, frozen grasshoppers. Such layers are probably remnants of vast migrations which have taken place at irregular intervals over several centuries. Great hordes of the insects either flew over the glacier or were carried there by winds, and while there sudden snow storms or cold air rising from the ice field caused them to drop. They were imbedded so quickly in the falling snow, which later became ice, that they have remained perfectly preserved for centuries. The most notable of these glaciers is in the Beartooth mountains of Montana. Others have been reported from the high mountains of Africa.

_Monster Clams of Polynesia_

Largest of clams and largest of all shellfish is a native of Polynesian seas. The two halves may weigh as much as 500 pounds. The flesh is eaten raw by natives. The interior of the shell is like polished marble. Such shells frequently were used as founts for holy water in European churches. A particularly large one attracted much attention in the Church of St. Sulpice in Paris. Such clams are found at depths up to 17 fathoms. They fasten themselves to rocks by a process so tough that it can only be severed with an axe.

_Corals Combine Plants and Animal Life_

A coral reef is a gigantic “plant-animal.” It is a community of countless billions of plants and countless billions of animals which act as a single organism, like the countless millions of specialized cells that make up the body of a man or a mouse. It is probably the most efficient of all earthly creatures. It is self-sufficient, creating its own constant food supply. It is essentially immortal. It is hungry like an animal. It is motionless like a plant. It is both and combines the attributes of both. It is the largest and most enduring of all creatures of land or sea.

The animals are coral polyps. They are tiny, wormlike organisms with mouths surrounded by constantly probing tentacles. They are rapacious and insatiable. They are essentially voraciously hungry stomachs, bloodless, brainless, sightless, heartless. The polyps are close to the bottom of animal life, vaguely related to the white, stinging sea nettles which are the scourges of summer beaches. These little creatures extract lime from sea water and secrete for themselves limestone “houses,” the “bones” of the superorganism. Out of these they have built up islands and almost subcontinents. Sharing their limestone cells are quite unrelated organisms, single-celled plants or algae. These plants possess the green of grass and forests, whose molecules create out of carbon dioxide and water through the energy of captured sunlight starches and sugars which are the fuel of animal life. This process of photosynthesis is the cornerstone of all life on earth.

Thus the plants feed their partner animals. The excretion of the animals, in turn, provides the essential fertilizer of the plants. Considering the coral reef as a superorganism one might almost say that it eats itself but loses nothing in the process. A reef, considered as a superorganism, represents about the last word in nature’s efficiency. It has been found, for example, that one acre of coral reef produces about 74,000 pounds of sugar a year, a record barely reached by man on his most efficiently managed plantations. All this sugar is devoured by the polyps. Apparently the fertility of the surrounding sea makes little difference. Coral reefs flourish in parts of the ocean that are essentially deserts.

A marine biological laboratory has been established by the U. S. Atomic Energy Commission, to study effects of the radiation from nuclear explosions on plant-animal populations. The first requirement has been to determine the natural condition of the organisms before being subjected to this radiation. Then whatever changes take place with subsequent bomb tests can be noted. The work has been undertaken by biologists of Duke University and the University of Georgia. Such a life community, both a vast assembly of organisms and a sort of superorganism, is an almost perfect subject for the required observations. The first job, according to the commission report, has been to measure the “basal metabolism” of the reef as a whole.

Admittedly the conception of a reef as a sort of superorganism is somewhat mystical. The Duke and University of Georgia biologists do not maintain that there is any consciousness of constituting a whole on the part of the individual organisms. It is likely that they have no consciousness of anything. The outstanding fact is that they behave so much like a whole.

A reef is an outstanding example of the two major divisions of life, plant and animal, working in perfect co-operation. The actual co-operation of plant and animal in an integrated organism is not unique for the coral reefs. Something of the sort occurs in certain sea worms, near the bottom of the worm family, that grow green algae in their blood streams. These worms make some of the beaches of Normandy grass-green in summer. The algae are necessary for their existence. There may be a few other examples throughout the animal kingdom.

_The First Engineers—Termites_

Termite civilization probably has reached its greatest heights in architecture and engineering. Australian mounds, built by workers out of earth particles cemented together by a salivary gland secretion, are steeple-shaped, as much as twenty feet high, and with bases twelve feet in diameter. Hundreds of such structures may be scattered over a few acres. Such an assemblage looks like a large native village, although architecturally the structures are far beyond the abilities of primitive man. The common type consists of a solid, hard outer wall which has the strength of superfine concrete. It is almost impossible to break through this material. Immediately inside are numerous thin-walled passages and galleries. Below these, at the ground level and about in the center, are the quarters of king and queen and the nursery. From the mound, passages for the food foragers lead in all directions through the soil. A mound two feet high will house approximately two million individuals.

Long before architects, termites developed the art of air conditioning. Proper humidity inside the nest is essential to the existence of the soft-bodied workers. The majority of species, however, are found in latitudes with long, dry seasons. To meet such conditions the insects achieved humidity control in various ways still not understood. Notable are the structures of the Australian compass termites who erect dwellings eight to twelve feet high with flattened sides. The broad ends always point east and west, the narrow ends north and south. These nests are strong enough to support the stamping of wild bulls. A group of them looks like a particularly well-constructed native village, or the site of some extinct human civilization. Apparently the precise orientation of the nests is associated with prevailing winds and in some way contributes to maintaining a constant humidity.

The blind creatures seem to have developed special sense organs, unknown to man and probably unique in the animal kingdom. One of these is reportedly a brain barometer which is extremely sensitive to slight humidity changes. Both soldiers and workers respond with military precision to any threat to their neighbors. This believed due to an extreme sensitivity to vibration.

Few varieties of termites can endure sunshine. Some construct paperlike umbrellas which they carry with them when they come above ground. One species on Barro Colorado island in the Panama Canal Zone which attacks live trees first builds a thin earth crust around the trunk, seven to eight feet from the earth. Beneath this crust they seek out weak spots in wood which enable them to penetrate into the heart of the tree.

Termite armies, in distinction from those of ants, serve only as defensive forces. There are two kinds of soldiers. Some are equipped with enormous jaws with which to rend the enemy. These are so tenacious that when the body is torn away from the prey the mandibles remain in place. Others are the bayonet men and chemical warfare troops. These fighters have a protrusion on the front of the head which looks like a long nose but which actually has developed from a primitive eye.

From this protrusion a sticky acid is exuded. In rare instance it may be spurted a short distance—an inch or less. These soldiers fight battles to the death with war-like ants which invade their nests. The termite warrior rams with his nose-like organ the so-called “pedicle” of the ant, the narrowest part of its body, smearing it with the liquid. This never has been completely analyzed. It is a powerful acid, but is not the well-known formic acid exuded by ants. It has strong corrosive properties when applied to metals. It has a pungent odor which, however, is characteristic of all termites and the ancestral cockroaches.

Between ants and termites there is perpetual war. Army ants, especially, try to raid termite nests to feed on the young whenever they can find any crack in the walls through which they can squeeze their bodies. But when there is any break in the nest the termite soldiers immediately arrange themselves in a circle around the opening while workers bring up little slabs of earth from the interior to patch the wall.

Most common of the Barro Colorado species are the amitermes which build hemisphere-shaped red mounds about two feet in diameter. These are made of tiny particles of earth which have passed through the alimentary tracts of the insects where they are coated with a cement-like material. Such a nest is impervious to water. It is so sturdy that a heavy man can jump up and down on it without breaking the roof. It cannot be broken open with a machete.

Another common species build the so-called “niggerhead” nests, about the size of footballs, on fence posts and trees,—especially dead trees whose stumps protrude out of Gatun Lake. These nests also are extremely sturdy. They are made of a mixture of earth grains and finely digested wood. From such a nest numerous runways traverse the trunk, sometimes connecting with smaller colonial “niggerheads.”

_Oyster Oddities_

An oyster can change its sex several times during its life. This has been determined by Dr. Paul Galtsoff of the U. S. Fish and Wildlife Service by observing an experimental colony. In the first year 8% of the males changed to females and 13% of the females became males. In the second year 11% of the males changed sex and 12% of the females. One sex change, Dr. Galtsoff found, makes the same individual more likely to undergo another.

A single Pacific coast oyster produces approximately 10,000,000,000 descendants a year. If all survived in five generations they would constitute a mass eight times the size of the world.

Clams and oysters appear to be about the most stupid animals in creation. Actually each has three “brains,” or nerve ganglia. One controls the feeding apparatus, another the viscera, and a third the utilization of oxygen.

_The World’s Biggest Sneeze_