On the other side of the globe, the country of Chile, in the shape of a long strip, lives a unique species of tern, the Inca tern (Larosterna inca), and when they reach adulthood, the slate gray they grow beautiful white long whisker feathers under the eyes, and the extra eye-catching features also give them a unique genus.
While the long white whiskers are dazzling, what's even more interesting is their call – "meow meow" like a cat.
Learn to cat bark
In known nature, only inca terns would meow like this. Of course, except for parrots and mynas who live with humans, imitations are not counted.
Some birds are known to be very good at imitating sounds, which can include the same species, other species and even artificial sounds (such as the alarm sound of electric motorcycles). Although it has nothing to do with terns, why do birds such as parrots evolve super imitative abilities? Scientists have come up with many hypotheses, but any speculative functional hypothesis so far lacks strong support, so the answer is not known.
Let the scientists study it slowly, at least the meow of the tern, certainly not learned.
Obviously it is a bird, how do you meow?
The vocal organs of birds have a proper noun, called syrinx, which is a bone structure located at the bottom of the trachea, while the "larynx" of our mammals is located at the top of the trachea.
In addition to the song tubes, birds also have cavities — sound waves are produced by thin films through which birds force air through. Birds control tone by changing the tension on the membrane, and tone and volume by changing the exhalation force. Some birds can independently control the two sides of the trachea, so they can make two notes at the same time and form their own harmonies.
As for why Inca terns meow, scientists can only assume that their song, like most other birds, evolved through sexual selection, and they like to listen to it, for no reason.
Studies have shown that the quality of the tern's "meow" is an indicator of their good health. When infected with parasites and diseases, it will affect the frequency of the call, and it will not be able to meow.
Birds chirping & singing
Some birds are very different from singing, while others are quite ugly. In general, the distinction between a bird's song and a call is based on complexity, length, and context.
The songs are longer and more complex, most of the time related to courtship; Calls often serve as alarms or keep group members connected. Many authoritative works in science have subdivided various types of calls.
The "meow" of the Inca tern, which is mixed with courtship songs, is also used for territorial defense. Since call quality is a reliable indicator of physical health, it is only natural that the intensity of competitors can be discerned by sound and prevent a costly battle.
"Well, this cargo is full of gas, must have strong internal strength, count it, meow ~"
"Inhumane" experiments
Among the bird species, the vast majority of the birds with beautiful songs are male birds. The Inca tern is also a male bird that meows more often.
In order to understand the mystery, in 2009, mad scientists in the United States conducted a study called "Gender Differentiation of the Vocal System": "denaturing" female birds - treating them with testosterone or dihydrotestosterone in adulthood.
Under the action of hormones, the female's brain is also disturbed and will show a singing behavior similar to that of males.
Other similar studies have attempted castration of male birds, and the results show that brain structure is key to singing, and hormones can have an effect (to some extent altering bird brain structure), but not absolutely. Because small males who are castrated or given sex steroid inhibitors at birth will also have singing behavior when they grow up.
Oh, in case one day by being taken away by aliens to do experiments, I feel that I am not qualified to complain, who let us humans do this virtue?
Write at the end
Forget about the annoying experiments, the birds' calls and songs belong to the language of birds, and the tireless efforts of scientists have brought us closer and closer to the day when we truly understand them.
For example, in the book "The Cognitive and Communicative Ability of Grey Parrots" published by Harvard University, it is shown that parrots have innate grammatical structural abilities, including the existence of concepts such as nouns, adjectives and verbs; For example, jackdaws have their own "names" to identify the members of the group, and when they start to prepare for flight, those "quacks" are calling friends - calling out the name of another bird, thus forming a "chain of relatives and friends", and so on.
Ha, I feel that sooner or later, there will be the perfect translation software, let us communicate with birds, animals, and even bugs! That way, you can roar at the mosquitoes that bit me last night: "Sun Zèi, don't run!" ”
The author thanks you for your attention (- _-)