Mice That Waltz to Save Human Lives

Sun (Auckland), Volume IV, Issue 934, 29 March 1930, Page 18

Mice That Waltz to Save Human Lives

Tiny Japanese Rodents Skilled in Jazz Steps Found More Sensitive to Deadly Carbon Monoxide than Canaries, and Therefore Valuable in Warning Miners of Gas Perils.

■ ROBABLY one of the strangest shows, and no doubt among the funniest, that human, beings have witnessed for many a day recently was offered the discriminating eyes of a group of staid scientists attached to the United States Bureau of Mines. First of all, two wee animals, looking for all the world like a cross between guinea pigs and commou house mice, were brought into the room in a small cage. Whereupon, to the delight of some of the scientists and the astonishment or others, the animals began a weird and crazy series of manoeuvres. Starting out with a sort or jerky scamper not unlike that of a fast-stepping comedy dancer, they came close to accomplishing a waltz step. But just as success seemed near, the animals performed in rapid succession a series o£ figure eights that would have done credit to a fancy skater. They then began to pivot uncertainly on one foot, performing a good many gyroscopic circles without stopping. “Are these queer animals drunk, or am I? And if not, what’s going on here, anyway?” a visiting scientist asked of a colleague. With a smile the latter enlightened him: “You’ve’been looking a-t what are known as Japanese waltzing mice. For some years they have been known in Asia, but until very recently their inane antics have been thought

to be valueless so far as their being of any help to human beings is concerned. “However not so long ago, in connection with an exhibition of ternsichorean skill such as you’ve just been witnessing, the astonishing fact was discovered by the Bureau of Mines that these frolicsome creatures are re ?Ponsive to concentrations of the deadly carbon monoxide gas than are canaries, long used by the bureau during important minerescue operations.” \ 9 ov , ernment expert went on to explain that the use of small animals such as canaries and mice, for exploring and detecting atmospheres contaminated with carbon monoxide depends on the fact that, due to their high metabolic rate and oxygen demand, accompanied by high respiratory exchange and rate of circulation they respond more quicklv than man to a given concentration of the gas From a practical viewpoint this, allows a margin of time between observable serious effects to the anima! and seri ° n ’ eflects to man ’ dur ing which period man can return in safety to fresh air

or else employ means of respiratory protection" It should be remembered, however that during the time the animal is incurring a detectable degree of poisoning man is also absorbing some carbon monoxide, and in some cases he may be seriously affected thereby, especially if the test animal is more tolerant than the average. The margin of time between effects in the animals and in man is not very wide, and experience with canaries has shown that an occasional bird may even be tolerant enough to fail to exhibit the looked-for symptoms before grave effects are noticeable in men. It is also known that carbon-mon-oxide poisoning, is augmented by considerable physical activity. This further increases both the demand for oxygen and the respiratory exchange and circulation of the blood. For this reason, when using animals for detecting carbon monoxide, the bureau experts have endeavoured to keep them as active as possible and, at the same time, to minimise the activity on the part of the men, thereby tending to increase the-sensitivity and widen the time between observable effects in birds and men. Numerous tests have been fairly successful when canaries have been used, but in the case of ordinary- house mice and white mice the animals tended to become more inactive and to huddle in the corners of their cage, thereby reducing their sensitivity. Having I learned these important facts, the ; bureau scientists conceived the Idea that perhaps, because of their incessant activity, Japanese waltzing mice might prove to be more susceptible to carbon monoxide than either canaries or common mice. This reasoning was borne out by comparative tests. In fact, the wee waltzers showed signs of response to the deadly fumes considerably in advance of their rivals. The signs were first manifested in | a weakness of the hind limbs and by the animals showing a tendency to ! fall while performing their characj teristic dances; later all their movements were slowed down; and still inter an almost complete inability to perform the movements. However, tlie recovery of the animals after their exposure to the dangerous fumes was rapid. Apart from their new-found importi ance, the waltzers are of interest to the student of strange animals. A major reason is that a mystery has' long surrounded them. Particularly is there a veil of uncertainty concerning their earliest history. Even the distinguished Professor Robert M. Yerkes, of Harvard, who has personally made the closest kind of investi- ; gatiou of the dancers, having bred a i great many of them and tested almost l countless others, is forced to admit that he has found no mention of them lin scientific literature prior to the i year 1890. There are a variety of in-eresting | descriptions of their weird nance by men who lay some claim to knowledge of the dancers’ intimate habits. One expert, for instance, says: "The dance, if such it be called, generally seizes the mouse when it emerges from its darkened sleeping place, and this would lead one to believe that the light conveys an impression of shock to the brain through the eyes, thereby disturbing the diseased centres and giving impetus to the giddy gyrations.” But Dr. Yerkes pooh-poohs this belief, pointing out that his extensive tests have proved to his satisfaction that the mice have a regular period of greatest activity contingent only upon the time element and that is between the hours of 5 and 10 pm. He further explains: "The most striking features of the ordinary behaviour of the dancer are restlessness and movements in circles. Even before it is old enough to escape irom the nest, it begins to move in circles and to exhibit the quick, jerky head movements which are character- | istic of the race.” Just as the stage and screen have their widely divergent types of dancing stars, so do the members of this queer animal family. There are three main types of dancing mice—those which twirl almost uniformly toward the right, those which cavort to the , left and those which manoeuvre about as frequently in one direction as j another. I