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Underwater, whales produce loud noises: known as songs. Scientists use whale songs to study the movements for migrations of groups of whales. Recently, scientists discovered something unusual: a single, solitary whale whose song is unlike that of all other known whales. The most notable difference between this unusual whale’s song and those of other whales is its high pitch or frequency. This unique whale is called the 52-hertz whale because it sings at the unusual frequency of 52 hertz, a much higher pitch than normal. When the 52-hertz whale was first detected, the cause of its uniquely high-pitched song was unknown; however, scientists now have several theories to explain it.

One theory holds that the 52-hertz whale may be a hybrid: the offspring of two different whale species. Whales of different species are known to interbreed and produce hybrid offspring that combine characteristics from each of their parents’ species. As a hybrid, the whale may have a unique song, different from that of either of its parents because it resulted from a combination of the two.

A second theory is that the 52-hertz whale may have a damaged sense of hearing. Just as people learn to speak by copying the sounds they hear, whales may learn to sing by listening to the sounds of other whales’ songs. When people are born deaf, their speech may sound different from that of people born hearing. Similarly, the 52-hertz whale’s songs may sound different simply because it cannot hear the songs of other whales.

A third theory holds that the 52-hertz whale may be the only known member of a rare species. Perhaps there were once many more whales of this species, but most are now gone. It seems to be entirely unique only because most of its species has died out.

Listening

听力原文

While scientists have attempted to explain the 52-hertz whale’s unusual song, each of their theories is flawed and the whale’s uniqueness remains a mystery.

First, it’s unlikely that the 52-hertz whale is a hybrid. Its migration pattern is too unusual. All hybrid whales that we know follow the migration pattern of non-hybrid whales, and so all hybrids typically travel together with normal whales. If the 52-hertz whale were a hybrid, it would likely do the same. By listening to the locations of 52-hertz whale’s song, however, scientists have been able to determine that it does not migrate alongside other whales. Unlike all the known hybrids, it has its own unusual migration pattern and migrates alone. 

Second, deafness or poor hearing cannot really explain one important feature of the 52-hertz whale’s song: its extremely high pitch. The pitch actually depends upon the physical structure of the whales, throat. You see, just like in humans, the vocal sounds that whales make originate in its throat in its vocal apparatus. To produce a song of such an extremely high pitch, the throat structure of this particular whale must be very unusual, and this unusual throat structure cannot be caused by a damaged sense of hearing because there’s typically no connection between hearing and throat structure. 

Third, it’s also unlikely that the 52-hertz whale is the only known member of a rare species. Even if the species was rare, the whale had to have parents. Those parents would have also sung at the 52 frequency. But the technology that detects the whales’ sounds underwater has been in use for many decades, so if other 52-hertz whales, such as the parents of today’s whale, had been around at a relatively recent time, scientists would have heard them. But no such whale song has even been heard before this one.

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