Zealand early in the last century. The Maoris regarded them with
superstitious awe and avoided them as much as possible. But early
British settlers and their dogs used to kill the inoffensive creatures
for sport. This was the first active enmity the tuateras ever had
known. They saved themselves by withdrawing to the barren islands and
becoming even more seclusive in their ways of life. Thus they clung to
a thin thread of existence until an enlightened government threw the
protection of the law around them.
Today the three-eyed lizard is probably the world’s most rigidly
protected animal. The New Zealand government has placed all sorts of
legal restrictions on hunting or capturing it, and to kill one would be
a major crime. For that matter, very few persons living ever have seen
a tuatera. It stays in seclusion most of the time. There is a single
specimen in the zoological park at Wellington. When a party from a Byrd
Antarctic expedition visited there they were told that the lizard had
not been seen for several months and that it was highly improbable that
it could be lured out of hiding. One day it would appear of its own
volition, take a philosophical look at the twentieth century, eat a few
flies, and retire to its lair under some rocks again. Here probably is
the secret of the race’s longevity. The little lizard has spent most of
its time sleeping. It has existed with the minimum of effort. It has
been satisfied with its lot and, above all, it never has gotten in the
way. It has been observed, for example, that one of the creatures never
climbs over even the smallest obstacle. It always will walk around.
_Prodigious Fertility of Insects_
The capacity of insects to reproduce is almost incalculable. A single
over-wintering house fly theoretically might have 5,598,729,000,000
descendants in a single year. It has been calculated that a single
cabbage aphis, which weighs less than a thirtieth of an ounce, might
give rise in a year to a mass of descendants weighing 822,000,000 tons,
about five times as much as all the people in the world. Fortunately
nearly all insects have an enormous mortality rate.
_The Lizard That Runs Out of Its Own Skin_
There is an animal that can get out of its own skin. It is a little
brown lizard, a gecko, which lives in native houses on the Palau
Islands in the South Pacific. This creature, about six inches long,
is closely related to the house geckos, which are found throughout the
tropical Pacific islands and as far north as Florida in the New World.
The Palau species is almost impossible to capture by hand.
Grabbed by the tail, it immediately sheds that organ. This is a rather
common practice among certain lizards and apparently brings little
inconvenience. A new tail can be grown. But as soon as a hand is laid
on this particular species it immediately and literally “runs out of
its skin.” This is done with lightning-like rapidity. The would-be
captor is left holding the animal’s empty skin. All the rest of the
lizard is running away, presumably seeking a hiding place.
This “running out of the skin” is a far different phenomenon than
that of shedding the skin by various reptiles, which always takes
place after a new skin has been formed underneath. The gecko just
abandons its skin altogether. It flays itself alive. Escape in this way
apparently is suicidal in most cases. That it ever could grow back a
complete skin is highly improbable.
_High Living in the Himalayas_
The highest land-dwelling animals on earth are small, black attid
spiders. They live in islands of broken rock on Mount Everest at an
altitude of 22,000 feet. This is far above the line of perpetual snow
and nearly a mile above the last vegetation. Since there is no other
living thing near them, they have to eat one another for sustenance.
Presumably their ranks always are being repleted by new arrivals from
below.
Highest of all living things are red-legged, black-feathered choughs,
birds of the crow family. A lone chough has been seen in the Himalayas
at 27,000 feet. There is an intimate association between these birds
and mountain sheep. The chough sits on the sheep’s back and searches
its hair for insects. The sheep seems to like this attention and stands
still while the exploration is in progress.
Another bird-animal association at high mountain altitudes is that
between mouse hares, rabbit-like animals about the size of large rats,
and finches. The hares live in burrows and usually are seen feeding at
the entrances or running from hole to hole. Both hares and birds are
seed eaters.
Wild sheep and mountain goats in the Himalayas struggle up to about
17,000 feet. There are small, wingless grasshoppers at 18,000 feet. A
few bees, moths and butterflies are found at 21,000 feet.
_Barking Spider Monkeys_
Barking spider monkeys that fight off unwelcome human invaders are
dominant animals in the “green mansions” of Panama jungles. They live
in semi-nomadic troops, each of which occupies a fairly restricted
area of the forest, sometimes overlapping slightly with areas of other
groups. Within their territory members of a troop wander freely, but
their activities tend to center around food and lodge trees.
In reporting on his observations of their activities Dr. C. R.
Carpenter of Columbia stated: “Almost every night the group slept
within earshot of camp. For eight successive nights they returned to
the same group of trees. Throughout the day the troop travelled, in
general, over the same routes from one food tree to another and from
favorite places in the deep forest where the midday siesta occurred.
Several other groups were regularly located in their own particular
home areas.”
The monkeys resent intrusion of their territories by anything that
looks like another monkey, such as a man. When approached they start
barking. The usual terrier-like bark of great excitement may change
to a metallic chatter repeated with great frequency. When males,
and sometimes adult females are approached closely they growl in a
strikingly vicious manner. Typically they come to the terminal ends of
branches, often within 40 to 50 feet of the observer, and vigorously
shake these branches. Both hands and feet may be used while the animal
hangs by its tail.
Throwing of branches is a conspicuous part of the reactions to men.
Quite frequently they break off and drop limbs close to the intruder.
Green branches sometimes, but most often large dead limbs weighing
up to ten pounds may be dropped. “This behavior,” according to Dr.
Carpenter, “cannot be described as throwing although the animal may
cause the object to fall away from the perpendicular by a sharp twist
of its body or a swinging circular movement of its powerful tail.
This dropping of objects from trees may be considered as a defensive
adaptation arising from the more generalized habit of shaking branches.
A significant variation occurs when the animal breaks off a limb and
holds it for a time—from a second to half a minute—before letting it
fall.”
Normally the monkeys travel along the upper surfaces of limbs, using
all four feet and carrying the tail arched over the back. When crossing
from one tree to another they use their powerful tails to support
themselves from limbs. During such movements hands, arms and tails
are used at the same time to make contacts with supports. The monkeys
have a strong tendency to keep their heads upward. Therefore, when
coming down a perpendicular limb, vine or tree trunk they go backwards
rather than head foremost. They frequently make long jumps outward and
downward, covering at times more than thirty feet
_The Insect That is Born Pregnant_
Among nature’s weirdest tricks is the strange phenomenon known as
merokinosis, reported for a single family of almost microscopic
insects. The little creatures are fathers and mothers before they are
born. They are a species of mite which infests grass. They belong to a
family which, almost alone among insects, gives birth to living young.
Nearly all insects are egg layers. The eggs, usually deposited in
enormous numbers, hatch outside the body of the mother. Then the
individuals go through a series of metamorphoses—nymph, larva and the
like—before reaching their own reproductive maturity.
These grass mites, however, are born fully adult animals. A sack on the
body of the female swells until it is about 500 times the original body
size. It is filled with eggs and a nutritive fluid. Within this sack
the eggs hatch and the new generation passes through all the ordinary
stages of insect metamorphosis. Finally, when they are fully mature,
the mother dies, the sack breaks, and the host of new mites emerges.
It was long thought that the mites were striking examples of
parthenogenesis, or asexual reproduction. Females isolated as soon as
they were born gave birth to large numbers of young. Parthenogenisis
is not uncommon among the lower animals. Invariably however, except in
this one case, all the offspring are of one sex. The supposedly virgin
birth families of the mites contain both males and females in various
proportions.
_Bull-dog Animals_
A repressed tendency towards the bulldog face apparently is deep-seated
among mammals. Foxes, cattle and pigs with bulldog appearance have been
reported. In three species of dogs—the bulldog, pug and the pug-nosed
dog of ancient Peru—this characteristic is dominant. It could have been
caused by a pronounced shortening of the rostral portion of the skull
due to the failure of facial bones to develop.
_Foresight of Kangaroo Rats_
A recent report by Dr. William T. Shaw tells of observations of giant
California kangaroo rats whose food consists largely of the seeds of
pepper grass. The seeds are gathered busily all day and stored in
shallow surface caches where they are dried by the dust and heat of the
sun. During the night, the animals work busily removing the dried seed
to much larger chambers deep underground where it is to be stored for
the winter. In some way the highly intelligent animal has learned the
secret of preventing mildew. Only a few other animals have mastered the
same technique; the beaver and cony dry their twigs in the sun before
storing them.
_The Primitive Proturans_
The proturans—blind, wingless minute bugs found under bark and in
leaf litter—are earth’s most primitive insects. They are seldom
seen and when they are noticed are likely to be mistaken for larvae
of some other insect. So obscure are the creatures that they were
not discovered until early in the present century. They are about a
twentieth of an inch long, yellowish, and covered with a protective
shell of chitin. Sluggish and slow-moving proturans have three pairs
of legs, only two of which are used for locomotion. The front pair is
held up in front of the insect as it moves. These legs apparently serve
the purpose of the antennae found in all higher insect orders. They are
provided with primitive sense organs of touch. These little creatures
presumably represent one of the earliest stages in insect evolution.
_Air-Conditioned Homes of Beavers_
Air ventilation of homes appears to be an engineering accomplishment of
beavers. “The beaver hut seen from the outside,” according to Sigvald
Salveson of Aamli, Nowayd, “appears to be so tight that it seems
astonishing that the occupants can get sufficient air. In winter, when
the lodge is covered with snow and ice one would not think it possible
that the animals could live in apparently air-tight dwellings. Near
my home is a small lake where a beaver built a dam and a great lodge.
In the outlet of the lake the water was still open and I noticed the
footprints of beaver on the thin ice just beyond. Twigs and small
trunks were dragged to the open water, where the animals sat on the
edge of the ice and took their meals. A fox had his usual track over
the lodge.
“More and more snow fell and the hut was more and more hidden under the
white blanket. Sometimes I noticed that the fox had gone to the top of
the dome and evidently sat there for a while. Near where he had sat
was a hole in the snow about half a foot in diameter and with thin ice
around the edge. I found that the hole widened downward and ended on
the roof of the lodge. At the bottom the hole was at least two feet in
diameter and its walls were hard as ice. From this hole or chimney rose
warm steam, and the twigs and mud on the roof felt warm and damp to my
hand.”
_The Demon of Puerto Rico_
In deep sunless ravines of Puerto Rico’s Pandura mountains dwells the
demon frog. It is a ghostly voice from mountainsides strewn with great,
decomposing granite boulders and so thickly covered with tropical vines
and bushes that it is almost impenetrable to man. Until twenty years
ago it was only a voice, for none of the strange little creatures ever
had been seen. The mere sight of the animal, according to many of the
natives, would be fatal.
“One might as well try to bribe a mountaineer to catch a ghost as
a guajone. There is a strange quality in the voice which probably
is largely responsible for the superstitious dread of the mountain
people,” according to Smithsonian Institution biologist Gerrit S.
Miller, Jr.
“It is strange enough when heard from the surface,” Miller reports,
“but it becomes even more strange after one has climbed down into
the irregular and dangerous openings, which prove to be much larger
and more cavernous than the surface appearance, with its dense and
deceptive covering of vegetation, could lead one to expect. With
flashlights the frogs are easily found and caught as they crawl slowly
over the damp, but not slippery surface of the granite.
“To the natives they are objects of dread. One man said they were about
a foot long and armed with frightful teeth. Another assured me that
anybody who saw one would die shortly afterwards. No offer of money
could induce the boys or men to go into the cavities in search of them.”
The little creature is fantastic in appearance, chiefly due to its
large protruding eyes. The edge of the eyelid is white, making a thin
white line around the eye. The iris is back and gold. The skin is
light brown above and nearly white underneath, but some specimens have
blotches of yellow which add to the weird appearance.
Living as they do in the semi-darkness of mountain gullies, little
is known of the life history and habits of these strange creatures.
The most notable characteristic of several specimens kept alive for
observation was the peculiar singing in a liquid note repeated six or
seven times. It can best be imitated by whistling. This singing is
believed to be part of the courtship behavior of males.
The demon frog has been given the scientific name of Eleutherodactylus
cooki. It appears to have been especially adapted for life among the
boulders of its restricted habitat.
_Man-Made Plants_
At least a half dozen species of plants are man-made. They are hybrids
which can transmit their basic and unique characters to future
generations.
The fact that what long was considered an impossibility in the plant
kingdom has been achieved is revealed by Dr. H. Bentley Glass,
professor of biology at Johns Hopkins University. With newly developed
techniques which make possible the doubling of chromosomes, bunches of
genes which are the units of heredity, the creation of species may be
just at its threshold and man may take over control of evolution.
The definition of species, after all, is the ability to produce
offspring with the major characteristics of the parents. The first
successful attempt, Dr. Glass says, was by a Russian geneticist
about 30 years ago. He crossed a radish and a cabbage and produced a
“rabage.” When two rabages were mated they produced seed which sprouted
into other rabages.
Unfortunately for the man who had been the first to cross one of the
great barriers in biology, the rabage was a pretty poor specimen. It
had the prickly, uneatable leaves of the radish and the poor root
system of the cabbage. Russian agricultural authorities had been led
to expect great things. They were bitterly disappointed that the new
vegetable did not fit into one of the five-year plans. The geneticist
was not heard of again and it is generally believed that he was
“eliminated” as a reward for one of science’s greatest achievements.
Creators of new species have fared somewhat better in other countries,
especially the United States, but they have not fared too well
anywhere. In practically every case the new species they have created
have taken over the worst characters of the parent species. They have
been of no commercial value. It is likely that about the same thing has
happened in nature throughout the milleniums.
But bad may be good. It all depends on the environment into which the
new species is born. Under the right circumstances, the rabage might
have superseded both radish and cabbage. That is, it might have been
adapted to a change in environment in which both parent species would
have become extinct.
Although no new animal species has yet been man-made there seems no
overwhelming reason why this should not happen with some of the new
chromosome-doubling drugs. However, a new kind of man is not likely.
Among higher animals the mechanism of heredity is very complex indeed.
It isn’t likely to happen in nature, in the face of atomic radiation.
It has been calculated that normally there is one human mutation per
generation for each 50,000 individuals. The high probability is that
this mutation involves a recessive, or hidden, gene. Its effects do
not appear in the population until two persons carrying the same
recessive are mated. About 999 out of 1,000 recessive genes are “bad”
and in due course will cause the extinction of the line in which they
appear. In the long history of the race it is likely that everybody has
fallen heir to one lethal gene, but it may be a long time making its
appearance in family lines.
Most of the genes in any given population, good or bad, are so hidden
that it is practically impossible to predict what the offspring of any
particular couple will be.
The recessive genes have vastly increased through the operation of
human “melting pots” all over the world in the last few generations.
One result is that minority races tend to become absorbed in
majorities. Thus the relatively small American Negro population,
without any further inter-marriage but purely through the cropping
out of recessives already received from the white majority, will be
entirely amalgamated in the more numerous race in approximately 2,000
years.
Genetics is getting into the hands of scientists tools which can speed
up the natural process of change about 1,000-fold and this may result
in either good or evil. The good side is well illustrated by hybrid
corn—a plant which cannot be considered a new species. This lately has
been carried to the point where corn with much more sugar in its stalks
and only six instead of twelve feet high can be produced.
_The Great Seal Migration_
The great annual northward migration of the seals is one of the
most remarkable phenomena of animal life. It seems to be without
organization and without leadership. Yet toward the end of March each
year the hundreds of thousands of cow seals and pups scattered over
thousands of square miles of water start at about the same time in
three great groups bound for three specific places. It has been the
same for centuries, perhaps milleniums. Each animal moves at about the
same rate so that all arrive within a few days of each other. Unlike
birds, they do not move in compact masses. Three great herds exist.
The American herd of about 1,500,000 is by far the largest of the
three. It goes straight to the Pribiloffs, where it goes ashore on
two almost barren islands—St Paul and St George. The Japanese herd,
numbering about 40,000, makes for Robben Island, off northern Japan.
The Russian herd, now estimated at about 200,000, goes to a few rocky
islands of the Commander archipelago off Kamchatka.
The moving herds consist almost entirely of females and young. The
bulls winter further north, tend to be solitary during the winter, and
precede the cows to the summer homes. The breeding season lasts for
about two months. During this time the bull never eats or touches a
drop of water. He never leaves the land. He arrives sleek and fat from
the ocean pasture and is able to survive entirely on stored energy.
This keeps him alive, even when he fights scores of terrible battles
with younger rivals. Towards the end of summer he naturally is a sorry
looking creature.
One day, actuated by some common impulse, cows and calves depart.
Then the bulls, their arduous labors of race propagation over for ten
months, draw back among the rocks for a long rest.
_The Magic Bark of the Cinchona Tree_
The shadow of a pale Spanish lady, dead for almost three centuries, has
returned to the dense rain forests of the western slopes of the Andes.
The shadow is that of the Countess of Chinchon, wife of the redoubtable
Don Luiz Geronimo de Cabrera Bobadilla y Mendoza, colonial viceroy of
Peru. She was dying of a strange disease in Lima in 1638. Her Jesuit
confessor, the story goes, gave a medicine to her doctor made from the
bark of a common Peruvian tree. It supposedly saved her life and two
years later she returned to Spain, carrying with her some of the magic
bark. Thus she gave to the world one of the supreme medicines of all
times. A century later the Swedish botanist Linnaeus tried to pay a
compliment to the long-dead beauty but misspelled her name—calling her
tree “cinchona”. Out of it came quinine.
The Andean forests remained for 200 years the only source of the magic
drug—quinine. The cinchona trees grew wild. They were stripped of bark
recklessly and became very scarce. By 1850 the price of quinine was $50
an ounce and only the rich could afford to have malaria.
The British tried to transplant the tree in India and failed. Then
Dutch botanists obtained some seed, planted it in the East Indies,
and developed high-yielding species. Soon this region became the sole
source of the world’s supply. The price dropped to 18 cents an ounce
and the lands over which the long-dead Countess had ruled dropped out
of the picture.
Now South American countries, notably Venezuela and Bolivia, are
reclaiming the crop with improved varieties of the cinchona tree, equal
to the best produced by the Dutch. They are regaining rapidly the dead
lady’s gift.
_Colombia’s Ant Tree_
In the sparsely inhabited, tropical portion of eastern Colombia is an
ant tree known as the barrasanta. It is a small, slender tree with
showy, red flowers which grows 25 to 30 feet in height. Both trunk and
branches are hollow and filled with masses of vicious, biting ants. As
soon as the tree is disturbed the insects swarm upon the invader. As
a result the tree is generally left alone both by Indians and white
settlers. The ants are protected by the branches and in turn protect
the host with their fighting prowess.
A curious shrub which grows out of enormous anthills found through the
llanos region of western Colombia furnishes quite a different example
of insect-plant association. The ants are “leaf cutters.” All other
plant life avoids their immediate neighborhood. This particular shrub
exudes a viscous, milky juice which traps any ants which try to climb
toward its leaves. Hence the insects have learned to leave it alone and
it enjoys the rich ant hill soil without competition from any other
plants.
_The Strange Behavior of Plants_
The behavior characteristics of some American plants are strange indeed.
The compass plant, a bristly perennial of the aster family which grows
in abundance over the prairies, is a living compass. It turns the edges
of its leaves in a general north-south direction. Another American
plant, the wild lettuce, does the same thing. The result is that when
the intensity of sunlight is weakest in the morning and evening the
flat surfaces of the leaves are in a position to receive the maximum
available amount of light. At noon, when there is more light than the
plant needs, only the edges of the leaves are turned towards the sun.
Then there is the English ivy which arranges its leaves in a mosaic
pattern so that about the greatest possible area is exposed to the
light. Other plants show equally precise adaptations to their light
requirements.