Western frontiersmen and others who live in the land of the pack rat relate stories innumerable of the absurd but industrious doings of these eccentric creatures. The ways of the pack rat are so erratic that I find it impossible to figure out by any rules known to me the workings of their minds. Strange to say, they are not fiends and devils of malice and destruction like the brown rat of civilization, and on the whole it seems that the destruction of valuable property is not by any means a part of their plan. They have a pa.s.sion for moving things. Their vagaries seem to be due chiefly to caprice, and an overwhelming desire to keep exceedingly busy. I think that the animal psychologists have lost much by so completely ignoring these brain-busy animals, and I hope that in the future they will receive the attention they deserve. Why experiment with stupid and nerveless white rats when pack rats are so cheap?

It was in the wonderland that on the map is labeled "Arizona"

that I met some astonishing evidences of the defensive reasoning power of the pack rat. In the Sonoran Desert, where for arid reasons the clumps of creosote bushes and salt bushes stand from four to six feet apart, the bare level ground between clumps affords smooth and easy hunting-grounds for coyotes, foxes and badgers, saying nothing of the hawks and owls.

Now, a burrow in sandy ground is often a poor fortress; and the dropping spine-clad joints of the tree choyas long ago suggested better defenses. In many places we saw the entrance of pack rat burrows defended by two bushels of spiny choya joints and sticks arranged in a compact mound-like ma.s.s. In view of the virtue in those deadly spines, any predatory mammal or bird would hesitate long before tackling a bushel of solid joints to dig through it to the mouth of a burrow.

Did those little animals collect and place those joints because of their defensive stickers,--with deliberate forethought and intention? Let us see.

In the grounds of the Desert Botanical Laboratory, in November 1907, we found the answer to this question, so plainly spread before us that even the dullest man can not ignore it, nor the most skeptical dispute it. We found some pack rat runways and burrow entrances so elaborately laid out and so well defended by choya joints that we may well call the ensemble a fortress. On the spot I made a very good map of it, which is presented on page 164. [Footnote: From "Camp-Fires on Desert and Lava" (Scribner's) page 304.] The animal that made it was the White-Throated Pack Rat (_Neotoma albigula_). The fortress consisted of several burrow entrances, the roads leading to which were defended by carefully constructed barriers of cactus joints full of spines.

The habitants had chosen to locate their fortress between a large creosote bush and a tree-choya cactus (_Opuntia fulgida_) that grew on bare ground, twelve feet apart. When away from home and in danger, the pack rats evidently fled for safety to one or the other of those outposts. Between them the four entrance holes, then in use, went down into the earth; and there were also four abandoned holes.

Connecting the two outposts,--the creosote bush and the choya,-- with the holes that were in daily use there were some much-used runways, as shown on the map; and each side of each runway was barricaded throughout its length with spiny joints of the choya. A few of the joints were old and dry, but the majority were fresh and in full vigor. We estimated that about three hundred cactus joints were in use guarding those runways; and no coyote or fox of my acquaintance, nor eke a dog of any sense, would rashly jump upon that spiny pavement to capture a rat.

[Ill.u.s.tration with caption: FORTRESS OF A PACK-RAT, AT TUCSON DEFENDED BY THE SPINY POINTS OF THE TREE CHOYA (_Opuntia fulgida_)]

Beyond the cactus outpost the main run led straight to the sheltering base of a thick mesquite bush and a palo verde that grew tightly together. This gave an additional ten feet of safe ground, or about twenty-five feet in all.

On our journey to the Pinacate Mountains, northwestern Mexico, we saw about twelve cactus-defended burrows of the pack rat, some of them carefully located in the midst of large stones that rendered digging by predatory animals almost impossible.

The beautiful little Desert Kangaroo Rat (_Dipodomys deserti_) has worked out quite a different system of home protection. It inhabits deserts of loose sand and creosote bushes, where it digs burrows innumerable, always located amid the roots of the bushes, and each one provided with three or four entrances,--or exits, as the occasion may require. Each burrow is a bewildering labyrinth of galleries and tunnels, and in attempting to lay bare an interior the loose sand caved in, and the little sprite that lived there either escaped at a distant point or was lost in the shuffle of sand.

The Gray Squirrel (_Sciurus carolinensis_).--This beautiful and sprightly animal quickly recognizes man's protection and friendship, and meets him half way. Go into the woods, sit still, make a noise like a nut, and if any grays are there very soon you will see them. The friendships between our Park visitors and the Park's wild squirrels are one of the interesting features of our daily life. We have an excellent picture of Mrs. Russell Sage sitting on a park bench with a wild gray squirrel in her lap. I have never seen red or fox squirrels that even approached the confidence of the gray squirrel in the truce with Man, the Destroyer, but no doubt generous treatment would produce in the former the gray squirrel's degree of confidence.

I never knew an observer of the home life of the gray squirrel who was not profoundly impressed by the habit of that animal in burying nuts in the autumn, and digging them up for food in the winter and spring. From my office window I have seen our silver- gray friends come hopping through eight or ten inches of snow, carefully select a spot, then quickly bore a hole down through the snow to Mother Earth, and emerge with a nut. Thousands of people have seen this remarkable performance and I think that the majority of them still ask the question: "_How_ does the squirrel know precisely where to dig?" That question cannot be answered until we have learned how to read the squirrel mind.

Small city parks easily become overstocked with gray squirrels that are not adequately fed, and the result is,--complaints of "depredations." Of course hungry and half-starved squirrels will depredate,--on birds' nests, fruit and gardens. My answer to all inquirers for advice in such cases is--_feed the squirrels, adequately, and constantly, on cracked corn and nuts, and send away the surplus squirrels._

At this time many persons know that the wild animals and birds now living upon the earth are here solely because they have had sufficient sense to devise ways and means by which to survive. The ignorant, the incompetent, the slothful and the unlucky ones have pa.s.sed from earth and joined the grand army of fossils.

Take the case of the Rocky Mountain Pika, or little chief "hare,"

of British Columbia and elsewhere. It is not a hare at all, and it is so queer that it occupies a family all alone. I am now concerning myself with _Ochotona princeps,_ of the Canadian Rockies. It is very small and weak, but by its wits it lives in a country reeking with hungry bears, wolverines and martens. The pika is so small and so weak that in the open he could not possibly dig down below the grizzly bear's ability to dig.

And what does he do to save himself, and insure the survival of the fittest?

He burrows far down in the slide-rock that falls from the cliffs, where he is protected by a great bed of broken stone so thick that no predatory animal can dig through it and catch him. There in those awful solitudes, enlivened only by the crack and rattle of falling slide-rock, the harsh cry of Clark's nut-cracker and the whistling wind sweeping over the storm-threshed summits and through the stunted cedar, the pika chooses to make his home. Over the slide-rock that protects him, the snows of the long and dreary winter pile up from six to ten feet deep, and lie unbroken for months. And how does the pika survive?

[Ill.u.s.tration with caption: WILD CHIPMUNKS RESPOND TO MAN'S PROTECTION. J. Alden Loring and his wild pets]

[Ill.u.s.tration with caption: AN OPOSSUM FEIGNING DEATH]

When he is awake, _he lives on hay, of his own making!_

In September and October, and up to the arrival of the enveloping snow, he cuts plants of certain kinds to his liking, he places them in little piles atop of rocks or fallen logs where the sun will strike them, and he leaves them there until they dry sufficiently to be stored without mildewing. Mr. Charles L. Smith declared that the pikas know enough to change their little hay piles as the day wears on, from shade to sunlight. The plants to be made into hay are cut at the edge of the slide-rock, usually about a foot in length, and are carried in and placed on flat- topped rocks around the mouth of the burrow. The stems are laid together with fair evenness, and from start to finish the haymaking of the pika is conducted with admirable system and precision. When we saw and examined half a dozen of those curing hay piles, we felt inclined to take off our hats to the thinking mind of that small animal which was making a perfectly successful struggle to hold its own against the winter rigors of the summits, and at the same time escape from its enemies.

The common, every-day Cotton-Tail Rabbit (_Lepus sylvaticus_) is not credited by anyone with being as wise as a fox, but that is due to our own careless habits of thought. It has been man's way, ever since the days of the Cavemen, to underrate all wild animals except himself. We are not going to cite a long line of individual instances to exhibit the mental processes or the natural wisdom of the rabbit. All we need do is to point to its success in maintaining its existence in spite of the enemies arrayed against it.

Take the state of Pennsylvania, and consider this list of the rabbit's mortal enemies:

450,000 well-armed men and boys, regularly licensed and diligently gunning throughout six weeks of the year, and actually killing each year about 3,500,000 rabbits!

200,000 farmers hunting on their own farms, without licenses.

Predatory animals, such as dogs, cats, skunks, foxes and weasels.

Predatory birds: hawks, eagles and owls.

Destructive elements: forest fires, rain, snow and sleet.

Now, is it not a wonder that _any_ rabbits remain alive in Pennsylvania? But they are there. They refuse to be exterminated.

Half of them annually outwit all their enemies--smart as they are; they avoid death by hunger and cold, and they go on breeding in defiance of wild men, beasts and birds. Is it not wonderful-- the mentality of the gray rabbit? Again we say--the wild animal must think or die.

In recognizing man's protection and friendship, the rabbit is as quick on the draw as the gray squirrel. In our Zoological Park where we constantly kill hunting cats in order that our little wild neighbors, the rabbits, squirrels and chipmunks may live, the rabbits live literally in our midst. They hang around the Administration Building, rear and front, as if they owned it; and one evening at sunset I came near stepping out upon a pair that were roosting on the official door-mat on the porch. There are times when they seem annoyed by the pa.s.sage of automobiles over the service road.

To keep hungry rabbits from barking your young apple trees in midwinter, spend a dollar or two in buying two or three bushels of corn expressly for them.

The sentry system of the Prairie-"Dog" in guarding "towns" is very nearly perfect. A warning chatter quickly sends every "dog"

scurrying to the mouth of its hole, ready for the dive to safety far below. No! the prairie-"dog," rattlesnake and burrowing owl emphatically do NOT dwell together in peace and harmony in the burrow of the "dog." The rodent hates both these interloping enemies, and carefully avoids them. The pocket gopher does his migrating and prospecting at night, when his enemies are asleep.

The gray squirrel builds for itself a summer nest of leaves. At the real beginning of winter the prairie-"dog" tightly plugs up with moist earth the mouth of his burrow; and he packs it with his nose. The round-tailed muskrat of Florida (_Neofiber alleni_) builds a little platform over the water of the marsh in which it lives, on which it builds its nest high and dry. The Hudsonian red squirrel will bark and scold at a human intruder for half an hour.

In Chapter IV I have already accorded the beaver a place with the most intelligent animals of the world. The books that have been written concerning that species have been amply justified. It is, however, impossible to refuse this important animal a place in any chapter devoted to the mental traits of rodents, and I deem it fitting to record here our latest experience with this remarkable species.

Our Last Beaver Experiment. In the autumn of 1921 we emptied and cleaned out our Beaver Pond. The old house originally built by the beavers in the centre of the pond, was for sanitary reasons entirely removed. Work on the pond was not finished until about October 25; and the beavers had no house.

It seemed to me a physical impossibility for the beavers to begin a new house at that late date and una.s.sisted finish it by the beginning of winter. One beaver had escaped, and for the remaining three such a task would be beyond their powers. I decided to give them a helping hand, provided they would accept it, by providing them with a wooden house, which they might if they chose, entirely surround and snugly cover with mud and sticks.

But would they accept it in a grateful spirit, and utilize it? One cannot always tell what a wild animal will do.

With loose earth a low island with a flat top was built to carry the house. Its top was six inches above high-water mark, and (that would, if accepted) be the floor of the permanent house. A good, practicable tunnel was built to an underwater entrance.

Upon that our men set a square, bottomless house of wood, with walls two feet high, and a low roof sloping four ways. Over all this the men piled in a neat mound a lot of tree branches of kinds suitable for beaver food; and with that we left the situation up to the beavers. The finish of our work was made on October 28.

For a week there were no developments. The beavers made no sign of approval or disapproval. And then things began to happen. On November 5 we saw a beaver carrying a small green branch into the house for _bedding!_ That meant that our offering was going to be accepted.

The subsequent chronology of that beaver house is as follows:

Nov. 10. The beavers pulled all our brush away from the house, back to a distance of six or seven feet. The house stood fully exposed.

Nov. 11. They began to pile up mud and sticks against the base of the south wall.

Nov. 15. Mud-building to cover the house was in full progress.

Nov. 17. Much of our brush had been placed in the stock of food wood being stored for winter use in the pond west of the house.

Nov. 29. The outside of the house was completely covered up to the edges of the roof. The beavers were working fast and hard. No freezing weather yet.

Dec. 15. The roof was not yet covered. Ice had formed on the pond, and house-building operations were at an end until the spring of 1922.