very active, and including some of the smallest marine fishes. A few
species attain full growth at about three-fourths of an inch. These are
the most notable of the “mouth breeders.” The female lays the eggs and
the male carries them in his mouth until they hatch. Inch-long males
sometimes carry as many as 400 eggs, nearly all of which hatch.
Other curiosities are the pipe fishes, hard-shelled animals which look
like bits of small, segmented pipe. They range from two inches to a
foot long and are related to the more familiar sea horses of temperate
waters. They are sluggish burrowers in coral reefs. As among sea
horses, the male gives birth to the young. The eggs are deposited in
pouches on the male’s belly where they are carried until they hatch.
_The Varieties of Raven Language_
While “nevermore” apparently is not in the vocabulary of the raven this
big black bird of the wilder parts of the country has a considerable
variety of sounds nearly as ominous.
Raven “language” has been intensively studied by the noted
ornithologist, Dr. Arthur Cleveland Bent. Citing various bird
observers, he lists the following calls:
A distinct, hollow, sepulchral laugh, haw-haw-haw-haw, which may be
heard at almost any time.
A series of “crawks” sounded while on the wing, interspersed with a
musical note that sounds like ge-lick-ge-lee.
A strange call like thing-thung-thung which is similar to the mellow
twang of a tuning fork.
Another expression has a metallic, liquid-like quality similar to the
song of the red-winged blackbird, although greatly magnified in volume.
Ravens have a large range of notes from the melancholy croaks with
which they chiefly are associated to striking imitations of other
birds, such as geese and gulls. One of these birds will talk to itself
for hours with a curious gargling sound. He becomes so absorbed in his
own conversation that it often is not difficult to steal up on him
during such a soliloquy.
“The raven,” Dr. Bent observes, “is one of our most sagacious
birds—crafty, resourceful, adaptable, and quick to profit by
experience. Throughout most of its range it is exceeding shy and wary.
It is almost impossible to get within gunshot of one in the open. Yet
it knows full well where and when it is safe. About northern villages,
where it is appreciated as a scavenger and seldom molested, it is as
tame as any barnyard bird.” This is especially true in Greenland where
ravens infest American air bases.
Although in the north the raven frequents the seacoast and villages,
from Pennsylvania southward it is entirely a mountain bird, usually
living above 3,000 feet. From these heights the birds sometimes descend
to the valleys, or even the islands along the coast, to forage among
the colonies of sea birds. Most of them prefer to dwell among rocks and
resort to perpendicular cliffs and to escarpments thrust above forests
on the flanks of mountains.
_Worms With Hypodermic Needles_
Despite their microscopic size, nematodes (soil worms), are highly
organized animals. They have muscles, quite specialized organs for
feeding, a digestive system, a nervous system with a brain, and a
well-developed reproductive system. Sexes are clearly differentiated.
The creatures have evolved a long way from the primeval worm.
Eggs may be deposited in the soil, or in the plant on which the
nematode feeds. In these eggs the immature forms, the larvae, develop
and eventually hatch. If appropriate plants are available, they may
begin to feed immediately. They develop through several distinct
stages. At the end of each of these cycles a moult occurs.
Many of the forms which have been studied closely have a minimum life
cycle, from egg to egg-laying female, of several days to several weeks.
The maximum duration of life, however, may be much longer, since sexual
maturity is not reached until the nematode begins to feed on the living
plant. Up to this time it remains in the larval stage and lives on a
reserve food supply originally derived from the egg. The time this
reserve lasts depends on circumstances. In damp, warm soil the nematode
will be very active and use it up in a few weeks. In cool or dry soil
the supply lasts much longer, and can extend to many years.
The little worm’s life is a perpetual struggle for existence. It
has many enemies in the soil—insects, fungi, and other free-living
nematodes. Certain of the soil fungi have “traps” especially designed
to catch nematodes. Some of these are shaped like loops which are
pulled tight as the worm starts to crawl through. Others are sticky
surfaces on which the victims are captured, like flies on flypaper. In
either case, the fungus grows into the body of the worm and kills it.
Nevertheless, the nematode population is never in any great danger
of extermination. A single female root knot nematode will produce
about 300 eggs in a couple of weeks. Allowing four weeks for a
generation, and assuming half the offspring are females, this implies
a theoretically possible fifty trillion individuals at the end of the
four generations of a single summer.
Practically all roots are attacked by some kind of nematode, but many
species appear to specialize on one type of plant and will not touch a
different variety, even if no other food is available. Plants immune
to one species may be highly susceptible to some other. A few kinds
of these worms, however, appear to eat almost anything they can find
underground.
All the root-eaters have a feeding organ which is much like a
hypodermic needle. This is pushed into the tissue and, it is believed,
a digestive juice of some sort is injected. This liquifies and
partially digests the food. Then the nematode sucks it through the
needle into its mouth.
The largest of the nematodes, a parasite of whales, can reach a length
of 27 feet. The smallest, a marine form, is a little more than a
three-thousandth of an inch long.
_The Fatal Black Widow Spider_
The venom of the dreaded Black Widow spider is approximately fifteen
times more potent than that of the rattlesnake. The comparison has been
established by determining the amounts of rattlesnake and spider venom
necessary to kill rats of the same weight. The extreme toxicity of the
spider becomes of considerable significance since it has been reported
from every state in the Union and may be increasing in numbers on the
edges of cities. Probability of being bitten, however, is slight. The
black widow is a timid creature, except towards her natural prey. At
the first molestation of her web she retreats quickly to her central
nest and does not venture out again for hours. She makes no attempt
at defense, to say nothing of aggression. Her reputation is so bad,
however, that in some cases pickers have refused to work in vineyards
which she infested.
_Plants That are Animated_
Among the curiosities often sold in American stores are so-called
“air plants”—plants that will grow on air alone without sunshine or
water. This is true, after a fashion. The “plants” actually are dried
skeletons of marine animals. They belong to the group which includes
the jellyfish, sea anemones and corals. Their skeletons have a striking
resemblance to plants.
The species most commonly sold is sea moss or Neptune’s fern, an animal
abundant in the North Atlantic, especially in the English channel and
the Gulf of Maine. A closely related species, the “squirrel’s tail,” is
abundant in the eastern Pacific where its silvery colonies often are
washed ashore by storms. Dry beach material of these colonies is easily
collected, dyed and sold as Christmas decorations.
“These are colonial forms consisting of thousands of individual
animals,” according to the Chicago Museum of Natural History. “Colonies
of two species of sea squirrel may be twelve inches or more long.
Those of some species may be several feet in length. Usually they are
attached to rocks or other substrata by a rootlike base, from which
spring the delicate branched stems bearing hundreds of minute polyps.
“Most of these are hydranths (feeding polyps) that capture microscopic
organisms. The reproductive polyps are less common, usually larger, and
different in shape. The common stem is made up of external non-cellular
material, mostly yellowish or brown in color.”
_The Tomato—Cinderella of Vegetables_
A remarkable chapter in the history of agriculture is the story of
the tomato which now constitutes one of this country’s major crops.
It appears to have first been used as a food by the Aztecs. It was
introduced into Spain early in the 16th century and a century later
was grown widely in England as an ornamental plant. Not until the next
century, however, did it have any standing as a food. It was known as
the “love apple” and was considered mildly poisonous. Folks ate one now
and then on “dares.”
Then it caught on as a food in Italy and by the start of the 19th
century was being grown on a field scale. So far as known, it was
absent from the gardens of Colonial America, unless as a rare
ornamental plant. Not until the middle of the 19th century was it
reintroduced to its native western hemisphere as a food crop. For a
long time it acquired no great popularity. A few vines in the family
garden were considered enough, since there was no tomato market.
A U. S. Department of Agriculture report calls the tomato “the prodigy
of the vegetable world.” Its present success is due in large part to
the discovery of vitamins. Although used as a food for little more than
a century it now is almost as widely distributed as wheat, a food plant
which has been cultivated for at least 5,000 years.
Today the tomato crop covers about a half million acres in the U. S.
alone. This crop consists of more than 20,000,000 bushels of fresh
tomatoes and more than 300,000 tons of canned products. There are now
about 150 known varieties, adapted to all sorts of purposes.
_The Holiest Place on Earth_
The summit of Adam’s Peak in south-central Ceylon, wrapped perpetually
in priestly robes of grey clouds, is one of the holy places of the
earth. There, through many centuries, the prayers of millions belonging
to warring creeds have worn thin the curtain between the effable and
the ineffable. It is a shrine of four of the world’s great religions.
In the rock is a depression that looks like a giant’s footprint. Hindus
believe it was made by snake-haired Siva, the destroyer. Moslems say
it is the footprint of the first man, Adam, who was exiled to this
mountaintop after he was thrown out of Paradise. Buddhists believe that
it could have been made only by the great Gautama. Nestorian Christians
maintain that it is a relic of the disciple Thomas, who brought the
gospel of Christ into the East. To this spot, braving the road through
leech-infested forests below and the perilous ascent along gale-swept
ledges, have come generation after generation of devout pilgrims
to voice a common prayer in different tongues through different
intermediaries.
The pilgrim, standing by the footprint of Adam, looks down upon the
forest-covered hills to the eastward. Over all the land spreads the
grey shadow of the supernatural. Below him is one of the most imposing
spectacles on earth—the middle slopes scarlet with the blossoms
of dense forests of gigantic rhododendrons, the deep-blue patches
of mountain lakes, and canyons which no human has entered—their
mysterious depths hidden by wind-tossed fog. Great waterfalls roar over
vine-covered cliffs. Strange sounds arise from jungles of white-stemmed
palms. It is a wild land of ghosts and demons watched over by the holy
mountains.
In this unearthly country native legend from ancient days has placed,
most appropriately, the death valley of the elephants. There, in a
pleasant hollow beside a lake of clear water—reached only by a narrow
pass with high walled precipices on either side—these animals make
their way from all over the island when they feel the chill drowsiness
of approaching death. It has been an interminable procession of the
doomed since time began. To the stricken old elephant, the coming of
death brings an irresistible nostalgia which draws his faltering
feet homeward to this mist-shrouded valley piled high with the white
bones of his ancestors. It is his haven of rest from the weariness and
disillusion of living.
The belief has deep roots in the ancient folk-lore of Ceylon. It has
spread all over the East. It is embodied in the Arabian Nights. No man
ever has entered this vale of death since Sinbad the Sailor, who was
carried there in the trunk of a huge elephant after he had been knocked
senseless when the tree in which he was hiding was uprooted by a herd
of the animals. Sinbad at last found himself in this valley piled high
with bones and knew that he was in the long-sought death place of the
elephants.
Another Ceylon elephant cemetery is concealed in a dense forest near
the ancient sacred city of Anardhupara. It is so well hidden that no
man knows its exact location, although all know that it exists. Unless
there are such cemeteries, the natives ask, what becomes of the remains
of dead elephants?
The death of the jungle elephant remains a fantastic mystery. No very
serious efforts have been made to provide a solution. Remains of these
creatures that have died natural deaths seldom have been found, either
in Asia or Africa. Yet obviously the great beasts are mortal, subject
to various fatal ailments and to the inevitable decay of age. Evidently
when one of them feels death approaching it retires to a place of the
dead where it quietly breathes its last and adds its bones to those
of the vast multitudes of its race that have gone before it into the
unknown.
The belief is so strong that there has been a persistent search for
these elephant Golgothas for the past century. Such a discovery,
especially in Africa, probably would mean inestimable wealth in ivory.
But, except for one or two questionable instances cited below, nobody
ever has found such a place. Natives sometimes claim to know an
approximate location from tradition, although they never have seen it.
Zoologists naturally frown upon the idea because of its very weirdness.
They explain that the remains of very few tropical animals ever are
found and that the elephant, for all its bulk, need be considered no
great exception. Vultures, jackals, hyenas and other carrion eaters
soon would tear the flesh from the bones. Insects would bear away the
fragments they left. Jungle vegetation rapidly would cover and hide the
naked skeleton.
Some credence is given to the native belief by Lieut. Col. Gordon
Casserly of the British army. A persistent elephant hunter during years
of service in India, he never came upon the carcass or bones of one
of these animals which had met a natural death. “The idea of a vast
death place of these modern mammoths hidden in the remote recesses of
the Himalayas,” he states, “did not seem a far-fetched one to me when
I lived in the shadow of those mighty mountains and heard at night the
great elephant troops pass by the little outpost that I commanded on
the frontier of Bhutan, as they clamber up towards the snow-clad peaks
from the forest below.”
The British elephant hunter W. D. M. Bell once thought he had found
one of East Africa’s elephant cemeteries in the country north of Lake
Rudolph. He had followed an elephant path to a grassy plateau strewn
with skulls and other elephant bones, some partially buried. None of
the remains, however, were recent. Bell tasted the green water of a
nearby pool and found it bitter with natron. The indications were that
large numbers of elephants had been driven to this pool to drink during
a time of drought and had been poisoned by the water.
Maj. P. H. G. Powell-Cotton tells of finding another spot strewn
with bones in the same general region which might answer the
specification for an “elephant graveyard.” “Here I was surprised,”
he reported, “to find the whole countryside scattered with remains,
the fitful sun lighting up glistening bones in every direction. In
all my journeyings through elephant country I do not think I have
ever come across before a skeleton of one of these beasts for whose
death the guides could not account. My guide called this place
‘The-place-where-the-elephants-come-to-die’ and assured me that when
the elephants fell sick they would come deliberately for long distances
to lay their bones in this spot. I had heard of these cemeteries from
Swahili traders who told me they had occasionally found more ivory
than they could carry. The place was well known to the Turkana, who
regularly visited it to carry off the tusks.”
_The Vanishing Golden Carpet_
The rarest plant in North America, found only four times by botanists,
is a ground-hugging desert flower—the gold carpet. The plant appears,
on rare occasions, in California’s Death Valley. Its appearance is
that of a rosette of yellow leaves, sometimes as much as ten inches in
diameter, lying flat on the ground. From this rosette arise innumerable
tiny golden yellow blossoms, so that the whole seems like a patch of
golden carpet in the brown desert. The reason for its rare occurrence
is that its seeds can germinate only after a good rain. Such rains are
rare in its habitat.
The plants must spring up within a few days. Ordinarily, even then,
they die with the increasing drought before blossoming—thus forming no
seeds. In order for them to produce the seeds for another generation
there must be another rain following shortly upon the first.
The seeds become buried in the desert soil and, in the course of
evolution, have developed the capacity of suspended animation over a
number of years. In the old days, it is probable, these seeds retained
their fertility only for a single season. Now there may be several
years between rains sufficient to spur them to germination, and even
longer periods between double rains which will enable them to form
seeds.
The strange little plant first was discovered in 1891. There were only
two specimens and search failed to reveal any more. Two years later,
however, at about the same place another single plant was reported. No
others were revealed by an intensive search through the entire area.
In 1931 and 1932 Dr. Frederick V. Coville of the U. S. Department of
Agriculture and French Gilman, a California botanist, again made an
intensive search but could not find a single plant. They came to the
erroneous conclusion that the plant might be native to the mountains,
from which occasional seeds were washed down after heavy rains. A
few years later Mr. Gilman again took up the search and succeeded in
locating the plant in four places. He found 14 individuals altogether
and watched their growth carefully. Only three became large enough
to flower and produce seed. The others dried up and died when they
had only a few leaves and no branches. Later, however, Gilman found
many specimens of the gold carpet scattered over low hills in the
neighborhood.
These little hills all were whitish in color. This led to the idea that
the chemical composition of the soil might have something to do with
the appearance of the plants. Analysis, however, showed there was no
basis for this assumption.
In the distant past, the gold carpet may have been a very abundant
plant, germinating and flowering annually in a reasonably moist
climate. Probably a few individuals developed the capacity of producing
seed which would remain fertile over a lapse of years. When the climate
changed these had a decided advantage over their fellows.
Apparently the gold carpet is a plant in the process of extinction.
The continued existence of the species depends on the dormancy of
a sufficient number of seeds to carry it over unfavorable years of
inadequate, or inappropriately timed second rains. If Death Valley
becomes drier and drier and years with suitable double rains become
more and more infrequent the vitality of the seeds in the soil
eventually will be insufficient to span the long periods when no seeds
are produced.
_Evolution of the Bird_
It’s a long call from the birds with teeth that hovered over the
strange world of the dying dinosaurs 150,000,000 odd years ago to the
chorus of sweet singers whose music opens sleepy eyes on May mornings
of the present. The long and devious road can be traced from the
grotesque archaeopteryx and archaeornis—nightmare-like and long extinct
flying creatures of the dawn—to the living wren and blackbird. But
however complicated, the family tree of birds is simple compared to
that of the reptiles or the mammals, since avian evolution has been
confined within narrower lines.
Up to the time that the monster reptiles were beginning to disappear,
it seems probable that all birds had teeth. Gradually, they disappeared
as the group advanced into the dawn age of present life forms. First
were the ancestral birds—the archaeornithes. They were essentially
winged reptiles. Following them came the toothed true birds of the New
World, known from very fragmentary fossil records. They included the
hesperornis, the hageria and the ichthyornis. Then, representing a
long advance, came creatures of the ostrich family, probably the most
primitive of living birds. They are true birds but have not reached
the typical modern pattern. At the top of the family tree, the highest
branch of bird evolution, is the great sub-order of song birds. It
includes fifty families ranging from the larks to the finches and
buntings.
_Speed Ace of the Air_
The swiftest bird flight ever recorded accurately is in the
neighborhood of 175 miles an hour. Ordinary, unhurried flight averages
from twenty to forty miles an hour.
The fastest flyer, according to official records, is the California
duck hawk whose speed was measured with a stop watch from an airplane.
Eagles apparently are much slower.
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.