MICKEY HAULS A LOG DOWN HILL TO HIS CANAL The author's night patrol of the pond shores enforced a fast on the beavers. The next morning, after several timid essays, hungry Mickey brought down a log from the plateau above. TOWING A LOG FROM THE BASE OF THE PLATEAU TO THE POND Another enforced fast, through fear of an all-night patrol, caused Mickey to tow this log a distance of 30 yards. The dark object in the left foreground of the inner foam circle is Mickey's tail. The author descried him one morning in a remarkable flurry; the body, wholly or in part submerged, was being rapidly driven in an orbit by the action of the tail, which had something of the whirl of a boat propeller instead of a sculling motion. whipped in a half circle, like a trout rod cast by a novice, and the objective tree fell clear. Mickey varied his usual procedure on the fifteenth afternoon. In the morning we noticed, floating near the dam, several large trees cut the night before. Mickey came at 4:29. His first act was to cut more large pond trees. When there were nine in all, instead of his usual preliminary work he towed the big trees in, laying them parallel with the dam wall, end to end, as near as the decaying, scrawny tops would allow, one trunk flow-pressed at the gap. Our film records this performance, with Mickey rearing up, and later peering at us as if to gauge our reaction to this new stunt. One of the big trees was 40 feet in length, by tape, and 10 inches in diameter at the butt. It was decayed by long submerging, so his underwater felling required the cutting of only four inches of live fiber. Green timber had been cleared from Mickey's lower flat, so he dug a canal to the base of a poplar-covered plateau five rods distant. Such canals may be designed for self-protection more than to ease the load, for a beaver can readily haul his logs overland. There are in Michigan the wolf, coyote, lynx, wildcat, and bear, any one of which would find the beaver on land an easy prey. If Mickey cut a 6-inch tree on the plateau, the trunk would be cut into logs two feet long; if the tree were smaller the logs might be four feet. THE WHOLE BEAVER FAMILY LAYS IN THE WINTER'S FOOD SUPPLY Mickey's canal was 30 yards in length and reached its objective by the most direct route available. It averaged about three feet in width, with a depth of more than two feet. In order to obtain a picture of his log towing, three of us patrolled the pond all night, enforcing a fast. a fast. Next morning, after several timid essays, he mustered hungry courage and brought several logs through within 12 feet of our blind. Later we employed similar methods When they are not working or playing, beavers are eating, sleeping, or primping. Both sexes are equipped with oil glands on each side of the lower body. Their hind feet carry queer toenail combs. With pressure of the paws the glands exude their hair-oil. They comb and oil and preen and primp in happy perseverance. This is a photograph of yearling beavers in captivity; all the other photographs with this article are of animals in their native state. in obtaining a picture of him as he hauled a log downhill. On all the locations we visited, beavers began to lay in the winter supply of food in late September. The whole family joined in the labor. Most of the logs were held submerged under trees previously anchored by insertion of the limb ends in the soft bottom. Some of the lone logs, apparently lying free on the bottom of the pond, got a deft dash of mud at end or side from a flirt of tail or paw before the beaver left them. In determining the trees to be taken, Mickey, like other beavers observed, appeared to select units that in his judgment would fall clear. As he surveyed things his actions conveyed his intent. Upright, braced by his broad tail, he seemed to note the correlation of his objective tree with its surroundings. Not satisfied with a single viewpoint, he would move around, peering upward in apparent study of conditions at another angle. On two occasions, after much investigation, which seemed to leave him in doubt, he forsook trees he had been examining and cut others. HOW THE BEAVER FELLS A TREE The beaver does not "gnaw" a tree down. Assuming that he has decided upon a tree, he puts in his felling kerf. This is made from 15 to 22 inches from the ground. During the operation he rests on his hind feet and tail. His first slash is above, the next, on a 6-inch tree, about five inches below. Then he takes out the same sort of chip which falls from the woodsman's ax. Penetrating past the heart, the cleft shows a decided upward slant. From the opposite side he hews through the remaining fiber and the tree falls (see page 751). During the 18 days of Mickey's repair work before my camera he never failed to show up within three minutes of the same time. There was the morning breach of the dam, with attendant lowering of the pond level. At four in the afternoon the pond would be silent, except for the plashing A WHITE SPLASH FOLLOWS THE BEAVER'S ALARM The "danger" signal is a resounding slap of the tail, always preceding a hurried dive. The slap and splash are often made in sport, however, and Mickey's last salute to the author was the "good-bye" slap which here disturbs the water. where we had tapped the wall and the rustle of grackle wings, as they flitted about in quest of food which the hatcheries of dead and dying timber afforded. Within a few minutes, out of the comparative silence would come the boom of a big bass bullfrog. Soon the tenor, alto, soprano. Then a general chorus, with swelling volume to the finale, which came with startling abruptness. The chorus would last for 15 minutes. Another period of silence, then riffles would break on the placid water, spreading in shimmering wavelets to each shore. We knew this to be the muskrat's calling card. Instead of sending it up he would take it down as he dived to visit with Mickey and the family. With one exception, at all the locations I had investigated, one or more muskrats came calling on the beavers in the late afternoon. Every evening they came on Mickey's pond, generally a pair, sometimes three. They would stay below for about ten minutes, then emerge with him. Mickey would sport with them for a few moments, then the muskrats would head upstream and he would swim over to note the damage at his dam. On the last day of repair, seven people, previously informed of Mickey's punctuality, witnessed his arrival on time. Space circumscribes this story of Mickey and his sedulous, sagacious activities, but if there be one who doubts the wonders in the beaver world, let him go in midsummer to the vicinity of the Crisp Point U. S. Coast Guard station, on the Lake Superior the conversion of a river's flow into a 3shore of northern Michigan, and view how mile line of seepage "basin" feeders created homes for scores of beavers where conditions had afforded homes for few. Note in the construction the use of water proof clays, brought a considerable distance from the only deposits of the kind in the vicinity. Or, locate a house in midwinter, with the temperature around 20° below zero, and note the vapors escaping by roof vents, which indicate that when the animal coated his house with congealing mud before ice sealed the pond, he planned a system of ventilation. L BY J. EDWARD HOFFMEISTER Professor of GEOLOGY, UNIVERSITY of Rochester, N. Y., and HARRY S. LADD ASSISTANT PROFESSOR OF GEOLOGY, UNIVERSITY OF VIRGINIA ANDS as well as people have their ups and downs. It is doubtful, however, if any land has been built up and cut down so often within the recollection of man as has Falcon Island. Located in the southwestern part of the Tonga, or Friendly, group of islands in the South Pacific, it has appeared, then disappeared from sight at least twice. In October, 1927, another eruption occurred which again raised it high above the level of the sea and brought it to the attention of men the world over. Since that time newspapers of many countries have published articles concerning its reappearance. Lavas have been reported flowing down its sides and great clouds of ash and steam rising several thousand feet above it. These reports came at long intervals during the winter of 1927-28 and were made by H. M. S. La- · burnum, the T. S. S. Tofua, and the S. S. Tutanikai, which on one or two occasions passed close enough to obtain good views. At this time the writers were making plans to continue geological work begun in 1926 in Tonga and Fiji, under the sponsorship of the Bishop Museum of Honolulu. It was decided that, if it were physically possible, a trip should be made. to Falcon Island and a landing effected. FALCON LOCATED ON VOLCANIC LINE The more exact location of Falcon Island is about latitude 20° 19′ S. and longitude 175° 25' W. If one could examine a geological map of this general region, he would find that all the volcanic islands lie in a straight line which runs in a north-northeast and south-southwest direction. Beginning with Mount Ruapehu, in North Island, New Zealand, through the Kermadec Islands, continuing through Ata (Pylstaart), Honga Tonga, Falcon, Tofua, Kao, Metis, Late, and Fanualai (Amargura), the volcanic islands of Tonga, and terminating in Samoa, this line includes one of the greatest chains of active and dormant volcanoes in the world (see map, page 760). It represents a line of weakness in the earth's crust and along it from time to time molten material is ejected. The world is made aware of these ejections only when the material reaches the surface and forms islands or shoals. It is very probable, however, that in many places along the line there are submarine volcanoes of whose existence no knowledge has ever been obtained. If one were to predict where the next new island in this part of the world would appear, it would be fairly safe to say somewhere along this line. Practically all the other islands of the region are of nonvolcanic rock, chiefly limestone. A HIDE-AND-SEEK ISLAND The island received its name when H. M. S. Falcon visited the spot in 1865 and reported a shoal. Twelve years later H. M.S.Sappho reported smoke to be issuing from the sea at the same position. In 1885 a submarine volcano burst suddenly into activity and built up a mound which, after a year of intermittent eruption, reached a height of at least 290 feet. In 1889, H. M. S. Egeria visited the island and Mr. J. J. Lister, an English geologist on board, made some careful observations. He found that during the four years since its formation the action of the sea had removed a large portion of the island, and that only about a third of the original mound remained. He calculated the maximum height of the island at that time to be 153 feet. Further observations were made by the British Admiralty in August, 1895. Falcon Island extended 800 yards in a northeast-southwest direction and 700 yards in a northwest-southeast direction. It was nearly circular in form and only 40 feet above water. |