Why Do Pirates Love Parrots? Read Free Page A

utilized infrasonic vocalizations, and she suspected that giraffes did, too. In 1998, she confirmed it by studying eleven giraffes in two zoos. Measuring infrasonic communication is difficult in the controlled atmosphere of a zoo, since passing cars, ambient wind, and even water create infrasound, but it is even more difficult in the wild, where other animals also can compete with the giraffes’ vocalizations.
    Muggenthaler and her fellow researchers discovered that the giraffes’ infrasonic vocalizations were associated with two physical movements: a “neck stretch,” when giraffes lift their head and necks over their bodies, and the “head throw,” that features a lowering and quick raising of the chin. Almost every time a giraffe was observed performing a neck stretch, an infrasonic vocalization accompanied it. Head throws were more common, but there giraffes vocalized only 25 percent of the time.
    Although it hasn’t yet been proven, Muggenthaler’s theory is that the infrasonic vocalizations might be caused by
     
         large volumes of air being forced up the neck and/or possibly channeled through hollow posterior sinuses. During the study, observers noticed a “shiver” or vibration extending from the chest up the entire length of the trachea that occurred during some neck stretches that accompanied vocalizations. It is possible that this “shiver” is air movement, and could be responsible for the signal. If air is [sic] moving up the giraffe’s neck is producing infrasound, the mechanism may be Helmholtz resonance, which occurs when an enclosed volume of air is coupled to the outside free air by means of an aperture.
     
     
    If giraffes are capable of vocalizing in a higher frequency through their mouths, why bother with the low-pitched stuff? One obvious advantage is that low-frequency sounds can travel farther than higher-pitched ones, a crucial advantage to giraffes (and elephants), who often are separated from their families by greater distances than their voices can reach. And although Muggenthaler’s team did not study how the giraffes use infrasonic vocalizations to communicate with each other, she does speculate about why infrasonic communica-tion might aid in giraffes’ survival. Evidently, we are not the only animals who can’t hear their low-frequency emissions:
     
         If the giraffes are communicating [with each other], it would be very advantageous for them, being prey, to be able to communicate “covertly” using signals designed to blend in with the background noise.
     
     
    Submitted by Peter Lanza of Stamford, Connecticut.

 
     

Why Do Some Slot Machines Use Fruit Symbols?
     
     
    W hen you think about slot machines, chances are you conjure up glassy-eyed gamblers in Sin City, Nevada, with cigarettes dangling from their mouths—hardly the setting for showcasing images of fresh fruit. Yet fruit was associated with slot machines almost from the time of their invention—in fact, in England, slot machines have always been known as “fruit machines.”
    Although there were mechanical gambling devices before, including a primitive precursor of today’s video poker machines, Charles Fey invented the first one-armed bandit in 1895. Fey’s Liberty Bell slot machine, with three reels sporting three of the four suits found in a deck of cards (clubs were the odd suit out) and the now-familiar cracked Liberty Bell. The highest jackpot, the princely sum of ten nickels, was won if you could line up three Liberty Bells in a row.
    Edibles came into the picture when the Mills Company of Chicago redesigned Fey’s original Liberty Bell and created a special machine for the Bell Fruit Gum Company. While most early slot machines were gambling devices placed in taverns (prizes were often a free drink or small amounts of money), Bell wanted a machine that could be played for a family audience at fairs and carnivals. Instead of playing cards, Bell placed drawings of fruits that