Alaska (4 page)

Nowhere else could the subtle relationships of nature be so intimately observed.

Ice high, oceans low. Bridge open, passageway closed. The ponderous mastodon lumbering toward North America, the delicate horse moving toward Asia. Mastodon lurching toward inescapable extinction. The horse galloping to an enlarged life in France and Arabia.

Alaska, its extremities girt in ice, served as a way station for all the travelers, regardless of the direction in which they headed. Its broad valleys free of ice and its invigorating climate provided a hospitable resting place. It really was an ice castle, and life within its frozen walls could be pleasant though demanding.

HOW SAD IT IS TO REALIZE THAT MOST OF THESE IMPOSING

animals we have been watching as they lingered in Alaska 22

during the last ice age and its intervals of friendly climate passed into extinction, usually before the appearance of man. The great mastodons vanished, the fierce sabertooth cats disappeared in mists that enclosed the bogs at whose edges they hunted. The rhinoceros flourished for a while, but then waddled slowly into oblivion. The lions could find no permanent niche in North America, and even the camel failed to flourish in the land of its origin. How much more enchanting North America would be if we had retained these great beasts to enliven the landscape, but it was not fated to be. They rested in Alaska for a while, then marched unknowingly to their doom.

Some of the immigrants did adjust, and their continued presence has made our land a livelier place: the beaver, the caribou, the stately moose, the bison and the sheep.

But there was another splendid animal who crossed the bridge from Asia, and it survived long enough to coexist with man. It had a fighting chance to escape extinction, and the manner in which it fought that battle is an epic of the animal kingdom.

THE WOOLLY MAMMOTH CAME OUT OF ASIA MUCH LATER

than the mastodon and somewhat later than the animals of which we have been speaking.

It arrived at a time of sharp transition when a relatively mild interval was ending and a harsher one beginning, but it adjusted so easily to its new environment that it thrived and multiplied, becoming one of the most successful examples of immigration and the archetypal Alaskan animal of this distant period.

Its remote ancestors had lived in tropical Africa, elephants of enormous size with long tusks and huge ears which they flapped constantly, using them as fans to keep their body temperature down. In Africa they browsed on low trees and pulled grass with their prehensile trunks. Admirably constructed for life in a tropical setting, they were magnificent beasts.

When such elephants moved slowly north they gradually converted themselves into creatures almost ideally suited to life in the high arctic zones. For example, their huge ears diminished in size to about one-twelfth of what they had been in the tropics, for now the animals did not require 'fanning' to enable them to live in great heat; they needed minimum exposure to the arctic winds that drained away their heat.

They also rid themselves of the smooth skin which had helped them keep cool in Africa, developing instead a thick covering of hair whose individual strands could be as long as forty inches; when they had been in the colder climates for 23

several thousand years, they were so covered with this hair that they looked like unkempt walking blankets.

But not even that was enough to protect them from the icy blasts of winter Alaska and remember that during the time we are now considering, the incursion of ice was at its maximum so the mammoth, already covered with thick, protective hair, developed an invisible undergrowth of thick wool which augmented the hair so effectively that the mammoth could withstand incredibly low temperatures.

Internally also the mammoth changed. Its stomach adjusted to the different food supply of Beringia, the low, tough grasses, wonderfully nutritious when compared to the huge loose leafage of the African trees. Its bones grew smaller, so that the average mammoth, markedly smaller than the elephant, would expose less of its body to the cold. Its forequarters became much heavier than its hind and more elevated, so that it began to show a profile less like an elephant and more like a hyena: high in front, tapering off at the back.

In some ways the most dramatic change, but not the most functional, was what happened to its tusks. In Africa they had grown out of its upper jaw in roughly parallel form, curved downward, then moved straight ahead. They were formidable weapons and were so used when males contested for the right to keep females in their group. They were also useful in bending branches lower for browsing.

In arctic lands the tusks of the mammoth underwent spectacular change. For one thing, they became much larger than those of the African elephant, for in some cases they measured more than twelve feet. But what made them distinctive was that after starting straight forward and down, like the elephant's, they suddenly swept outward, far from the body, and down in a handsome sweep. Had they continued in this direction, they would have been enormous and powerful weapons for attack or defense, but just as this seemed to be their purpose, they arbitrarily swung back toward the central axis, until at last their tips met and sometimes actually crossed, far in front of the mammoth's face.

In this bizarre condition they served no constructive purpose; indeed, they hampered feeding in summer, but in winter they did have a minimal utility, for they could be used to sweep away snowdrifts so that mosses and lichens hiding below could be exposed for eating. Other animals, the bison for example, achieved the same result by merely pushing their big heads into the snow and swinging them from side to side.

Protected against the bitter cold of winter, adjusted to the plentiful forage of summer, the mammoth proliferated and 24

dominated the landscape long after the much larger mastodon had vanished. Like all other animals of the early period, the mastodon had been subject to attack by the ferocious sabertooth, but with the gradual extinction of that killer, the mammoth's only enemies were the lions and wolves that tried to steal young calves. Of course, when a mammoth grew old and feeble, packs of wolves could successfully chivvy it to death, but that was of no consequence, for if death had not come in that form, it would have in some other.

Mammoths lived to fifty or sixty years, with an occasional tough customer surviving into its seventies, and to a marked degree it was the animal's nature of death that has accounted for its fame. On numerous occasions in Siberia, Alaska and Canada so numerous that statistical studies can be made mammoths of both sexes and all ages stumbled into boggy pits where they perished, or were overcome by sudden floods bearing gravel, or died at the banks of rivers into which their carcasses fell.

If these accidental deaths occurred in spring or summer, predators, especially ravens, quickly disposed of the cadavers, leaving behind only stripped bones and perhaps long strings of hair, which soon vanished. Accumulations of such bones and tusks have been found at various places and have proved helpful in reconstructing what we know about the mammoth.

But if the accidental death took place in late autumn or early winter, there was always the possibility that the body of the dead animal would be quickly covered with a heavy layer of sticky mud that would freeze when hard winter came. Thus the corpse would be preserved in what amounted to a deep-freeze, with decay impossible.

Most often, one has to suppose, spring and summer would bring a thaw; the protective mud would lose its ice crystals; and the dead body would decompose. Disintegration of the corpse would proceed as always, except that the freezing would have postponed it for a season.

However, on rare occasions, which could become quite numerous over a time span of a hundred thousand years, that first immediate freezing would for some reason or other become permanent, and now the dead body would be preserved intact for a thousand years, or thirty thousand, or fifty. And then, on some day far distant when humans ranged the valleys of central Alaska, some inquisitive man would see emerging from a thawing bank an object that was neither bone nor preserved wood, and when he dug into the bank he would find himself facing the total remains of a woolly mammoth that had perished in that bank thousands of years ago.

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When the accumulation of viscous mud was carefully cleaned away, a remarkable object would be revealed, something unique in the world: a whole mammoth, long hair in place, great tusks twisting forward and meeting at the tips, stomach contents in the condition they were when it last grazed, massive teeth in such perfect condition that its age at death could be accurately calculated within five or six years. It was not, of course, a standing animal, plump and clean within a case of blue ice; it was flat, plastered with mud, disgracefully dirty, with leg joints beginning to come apart, but it was a complete mammoth, and it revealed to its discoverers a volume of information.

This next point is important. We know about the great dinosaurs who preceded the mammoth by millions of years because their bones have over the millennia been invaded by mineral deposits which have preserved the most intimate structure of the bone.

What we have are not real bones, but petrified ones, like petrified wood, in which not an atom of the original material remains. Until a recent find in far northern Alaska, no human being had ever seen the bone of a dinosaur, but everyone could see in museums the magically preserved petrifications of those bones, photographs in stone of bones long since vanished.

But with the mammoths preserved, by freezing in Siberia and Alaska, we have the actual bones, the hair, the heart, the stomach, and a treasury of knowledge that is incomparable.

The first of these icy finds seems to have occurred by accident in Siberia sometime in the 1700s, and others have followed at regular intervals thereafter. A remarkably complete mammoth was uncovered near Fairbanks in Alaska not long ago, and we can anticipate others before the end of the century.

Why has it been the mammoth who has been found in this complete form? Other animals have occasionally been uncovered, but not many and rarely in the excellent condition of the best mammoths. One reason was the substantial numbers of the breed. Another was that the mammoth tended to live in those peculiar areas in which preservation by freezing mud was possible. Also, its bones and tusks were of a size to be noted; many birds must have perished in these areas in these times, but because they had no heavy bones, their skeletons did not survive to keep their skin and feathers in position. Most important, this particular group of mammoths died during a time of glaciation when instant freezing was not only possible but likely.

At any rate, the woolly mammoth served a unique function, one of inestimable value to human beings; by freezing quickly when it died, it lived on to instruct us as to what life

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was like in Alaska when the ice castle functioned as a refuge for great animals.

ON A DAY IN LATE WINTER, TWENTY-NINE THOUSAND

years ago, Matriarch, a mammoth grandmother, forty-four years old and beginning to show her age, led the little herd of six for which she was responsible down a softly rolling meadow to the banks of a great river later to be known as the Yukon. Lifting her trunk high to sniff the warming air and signaling the others to follow, she entered a grove of willow shrubs that lined the river, and when the others had taken their places beside her, she indicated that they might begin feeding on the sprouting tips of willow branches. They did so with a great deal of noise and movement, for they were glad to escape the meager rations they had been forced to subsist on during the recent winter, and as they gorged, Matriarch gave grunts of encouragement.

She had in her herd two daughters, each of whom had two offspring, heifer and bull to the elder, bull and heifer to the younger. Severe discipline on these six was enforced by Matriarch, for the mammoths had learned that the survival of their species did not depend very much on the great males with their tremendous showy tusks; the males appeared only in midsummer for the mating period; the rest of the year they were nowhere to be seen, so they took no responsibility for rearing and educating the young.

In obedience to the instincts of her race, and to the specific impulses which stemmed from her being female, she devoted her entire life to her herd, especially to the young. She weighed, at this time, about three thousand pounds, and to keep alive she required each day some hundred and sixty pounds of grass, lichen, moss and twigs, and when she lacked this ample supply of food she experienced pangs of biting hunger, for what she ate contained only minimum nourishment and passed completely through her body in less than twelve hours; she did not gorge and then ruminate like other animals, chewing her cud until every shred of value was extracted from it. No, she crammed herself with vast amounts of low-quality food and quickly rid herself of its remains. Eating had to be her main preoccupation.

Nevertheless, if in her constant foraging she caught even a hint that her four grandchildren were not getting their share, she would forgo her own feeding and see to it that they ate first. And she would do the same for young mammoths who were not of her own family but under her care for the moment while their own mothers and grandmothers foraged

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elsewhere. Even though her stomach contracted in emptiness and pain with warning signals shouting 'Eat or perish!' she would first attend to her young, and only when they had been provided with grass and twigs would she browse the birch tips and harvest the good grasses with her noble trunk.

This characteristic, which separated her from the other mammoth grandmothers, had developed because of her monomaniacal affection for her children. Years ago, before her youngest daughter had borne her first offspring, a onceprepotent older bull joined her herd during the mating season, and for some inexplicable reason, when the mating was completed, he remained with the herd when normally he should have left to join the other bulls who foraged by themselves until the next mating season came around.