Criminals Beware

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THE DAM BUILDERS

By: Tuvia Cohen



Everyone loves a sebet. Since the sebetcomes immediately after Shabbat morning prayers, it quenching our hunger. That’s even more true for a Bar Mitzvah, when praying is a bit longer and the Torah reading and speeches longer still. As the marathon performance draws to a close, the thought of the food awaiting us at the sebetis enough to make our pangs of hunger a palpable force. As the famished congregants make their way from the synagogue to the adjoining hall, the threat of being trampled amidst the human avalanche is real!

Imagine that you, tzaddikthat you are, wish to teach patience to the hungry crowd. You position yourself in the doorway, your arms and legs spread-eagled across the opening, and stop. At first you hear impatient “Nu’s.”Then the volume of the “Nu’s”increases. The strain on your back, as 200 hungry people push forward, is difficult to withstand. Desperately, you hold your position, the force increasing until, finally, the sheer pressure of the crowd washes you away like a twig in a raging river. It was a brave, but futile try.

If holding back peopleis difficult, how much more so would that apply to
surging water?

Everyone has heard of, or seen, dams. Dams allow water to be stored in reservoirs, controlling the water supply throughout the year. Water from a reservoir can be used to drive turbines, which provide electricity. But how do you set about building a dam? Keep in mind, dams have to withstand more pressure and weight than any other
man-made structure. The massive Hoover Damon the Colorado River is a colossal 577 feet high, and holds back 38 billion tons of water!

In the 20thcentury, dam building represented the peak of engineering, skill and imagination. The effort to construct them has produced daring and original structural forms. Choose your favorite: Gravity dams (which rely on their weight to resist the horizontal forceof the water), arch dams (which transfer the pressure of the water to the sides of the valley) or a combination of both, as is the case with the celebrated Hoover Dam. Either way, the complexity and difficulties involved in enacting a dam stagger the imagination. In 1988, the world’s largest hydroelectric generating plant was completed after nearly 14 years of work by 40,000 men. This involved damming the River Parana, the fifth largest river in the world, which forms the border between Brazil and Paraguay. There is no doubt about it. You have to be clever to dam a river…

*****

Sorry, there’s been an interruption!
I have a small creature here (two-and-a-half
feet long, a foot high and about 50 pounds) who seems a little agitated. He’s been damming rivers since he was created, and he doesn’t understand what all the fuss is about! Speak up, Mr. Beaver!

Listen carefully and you will hear – Crash! The cool stillness of the forest is suddenly shattered by the sound of a young tree falling to the ground. A small,brown, furry creature scurries through the undergrowth and slips into the nearby river for safety. It waits there until it is sure that no enemies have been attracted by the noise, then returns to the tree. Its strong front teeth set to work gnawing through the branches, stripping the trunk bare. The North American beaver then grasps the trunk in its powerful jaws, and drags it into the water. The creature tugs and pushes the trunk into position, amongst the mound of branches, twigs, mud, and boulders, which makes up its dam.

Pause for a moment, and consider the remarkable little animal that has built this amazing structure. His back feet are webbed like a duck’s, his forefeet are strong, and his little hands are agile, like a monkey’s. He also has a broad,scaly, multi-purpose tail. It’s used as a rudder when swimming, a prop when standing or sitting, and a transmitter of news always. When a beaver scents danger, he spanks the water with his tail. On quiet days, the ringing noise can be heard a quarter of amile away, causing every beaver within earshot to disappear. If you surprise a beaver on land, he will not fight back. Instead, he will run for his pond, dive like an expert and swim like a champion. He possesses the ability to close his nose and his earswhile doing so, as transparent coverings slide down over each eye so that he can see underwater. Mr. Beaver relaxes his muscles, and drops the rate of his heartbeat by half, allowing him to remain underwater for 15 minutes. Each of these features is noteworthy, for, without them the beaver could not survive.

But none are as extraordinary as the beaver’s teeth, which number 20 in all. The four front teeth, strong and curved, are covered with unbreakable enamel. Called incisors, they grow constantly and are used for gnawing through the trunks of trees. The 16 back teeth are used for chewing. Between the incisors and the back teeth are flaps of skin, one on each side of the beaver’s mouth. These flaps fold inwards, and seal off the back of the mouth to preventboth splinters of wood and water from entering the beaver’s lungs.

The beaver’s logging abilities are as amazing as his carpentry and engineering skills. Standing on his hind feet, using his tail as a support, he eats around a tree. Before long, what will become the stump and the falling tree appear like smooth, tapering spikes, balanced point upon point. Either the wind or the law of gravity finally brings the tree crashing down. While beavers prefer saplings,
a tree that’s 18 inches thick presents no problem. Why does
Mr. Beaver need to fell trees? Both to acquire his food, and to build
the dam for which he has deservedly achieved such fame and renown.

It is the icebound Northern winter that prompts a beaver to build a dam in the first place. Winter means no open water to plunge into for refuge, additionally, layers of snow make finding bark to eat difficult. So our industrious beaver creates a personal pond, in whose muddy base he can anchor a whole winter’s supply of eating timber, and on which he can build an impregnable mansion for himself and his family. He begins by felling a tree near a river, causing it to jam near the point where he intends to build. Once set, the tree catches silt and driftwood, and the beaver furiously lugs in material from theriverbanks; mud, sticks, stones and grass, which he consolidates into one mass for the dam he is building. Mud, its major ingredient, is carried in his hands. During his dives to the dam’s foundations, he works it into place using his hands and the side of his face for leverage. He begins in the middle, and continues to build towards either shore.

How wide is his dam? Think big! It can be between 10 and
2,000 feet long! The current record is held by a 2,100-foot dam, located in the state of Montana. Once the dam is completed, and the water level established, the beaver then builds a home for his family, called a lodge. This lodge may be fixed to the dam, to the shore, or to an island in the pond. Its foundation is builit upon sticks, stones, and twigs, woven so professionally that it cannot dissolve or collapse. The dome-shaped lodge is built from branches, reeds, and mud. There are two entrances – through the floor and under the water. One can act as an escape hatch if submersible enemies enter to pay an unwelcome visit! The top of the lodge, made of heavily woven thatch, is not completed until freezing weather sets in. Then, the beaver plasters it thickly with mud, which freezes into an armor plate often ten inches thick. Nothing that prowls, from a bear toa lynx, has the strength to tear through that roof.

The fact that beavers are sociable, peaceful, industrious, and faithful is admirable. The fact that they are fully equipped to chop down trees, build solid dams, and intricate homes without the assistance of a single machine is an inspiration. No amount of wishful thinking will enable you to grow a security tail, webbed feet, transparent eyelids, or self-replenishing teeth - but Mr. Beaver, dam builder extraordinaire can thank the Creator, Who designed and formed him with such wisdom.

Tuvia Cohen, is a humorist, scientist, and an accomplished author.