When the people of the houseboat in California heard a low rumble underwater, they put forward a variety of suggestions. It could be noisy sewage, military experiments and even an alien invasion. However, these hypotheses have been proved to be far from the truth. In fact, these sounds belong to male-midshipman fish. So in the twentieth century, the 80-year-old biological puzzle has been solved. Singing fish that live along the western coast of the United States, have been sent to a laboratory for examination. The scientists had to find the cause of nocturnal chants. In truth, these sounds are like remote singing.
The biological clock
Researchers have discovered an interesting pattern. Chants occur under the control of the melatonin hormone which is always in sync with the daily rhythm of the fish. The absence of sunlight triggers the release of the hormone responsible for sleep in humans. This factor makes the inhabitants of coastal ocean waters issue lingering buzzing sounds!
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Backlash on melatonin
If people want to sleep at nightfall, and singing birds complete their trills, then-midshipman fish show a different picture. Melatonin – a hormone that controls the body clock in humans, which is responsible for the change of wakefulness and sleep cycles, a large amount of light (eg, light fixtures and gadgets running at night) inhibit its ejection. However, nature-midshipman fish is not subject to conventional biological laws. So, forced injection of melatonin in the daytime has prompted them to renew a prolonged roar. When the scientists came to this result, they had to examine the effects of the hormone on brains of the regions fish. This chemical was really active in the areas responsible for the “singing” parts of the brain.
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A little history
Study leader Professor Andrew Bass said that his interest in such an amazing sight as the midshipman fish was triggered by a scientific article published in the distant 1924. In his report, Charles Green described how male midshipman fish’s lingering issue echo sounds to attract females. The fishes do it only at night, and their natural habitat does not extend beyond the coast of California. Females, in turn, also make sounds, however, are not so typical. Loud choir “singing” – is the prerogative of males guarding their territory. With the onset of spring, these vociferous fish build nests and sing all the time. They need to have time for a short season to leave offspring.
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Where did the funny name come from?
Most observers of the first fluorescent fish saw striking similarity in appearance of the fish and the individual shape of the midshipmen of the Naval Academy, and thus created funny name.
Why the same hormone has different effects on different types of species?
Let’s go back to our experiment. The study’s authors believe that nature has made them differently sensitive to melatonin in order to protect from predators. If these fish struck up their songs in the afternoon, with the active sunlight, they would have a much better chance to attract the attention of the predators. So the same chemical can cause diametrically opposite reactions across species. If the daytime birds (eg, birds) with the release of melatonin are preparing to sleep, then midshipman fish’s phase only begins awakening.
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The researchers hope that their experiment will be useful to examine the relationship of hormones and reproductive behavior in songbird species of vertebrates. This example once again convinced us that the mechanism of action of hormones on living species is still not fully understood.
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