Recently, we
wrote about the unusual acoustics of man-made spaces and natural locations. Today we publish interesting sounds of nature, discovered by scientists.
Which of the animals sounds like jazz music, and who can imitate the human voice - tell in our compilation.
Photo by DickDaniels CC BY-SAHummingbird males control the sound of their flight
In the process of evolution, birds have developed unusual behavior in order to attract their mating partners: tent-birds make intricate nests, and the color of wings of some paradise birds is so dark that it resembles a natural
vantablack . The changes also affected the bird vocalizations - male hummingbirds of the species
Kalipta Kosta (Latin Calypte costae) manipulate the sound of their flight to attract a female.
“People like hummingbirds, their performances are always exciting and attractive, but we know little about them,” said Christopher Clark (
Christofer Clark ) researcher at the University of California at Riverside.
Scientists
have studied the behavior of hummingbirds during a dance for a female. The study measured the sound and direction of flight, used microphones and devices that can display sound, its intensity and source, and even the wind tunnel. As a result of the experiment, it turned out that males dive aside, instead of “dancing” directly in front of the female - they want to demonstrate their physical strength, showing how fast they are.
Males “tune” the sound of a dive: they twist part of the tail and change the flight path. All this
helps them to minimize the Doppler effect for the observer (female) - and thus not allow her to more accurately determine the speed of flight. In addition, the hummingbird male moves the tail feathers towards the female, which also affects the volume. However, it remains unknown how female hummingbirds actually react to different combinations of loudness and pitch — whether they measure them, and which variant they prefer. Evaluation of the reaction of the female individual is the next step in the study of the sexual selection and communication of these birds.
The sounds of a swarm of midges
The sensitivity of blackflies to sound was discovered as far back as the 1960s and is still being researched. Swarms are entirely made up of male midge. Males have long antennae and flap their wings twice as often as females. Attracted by high-pitched sounds, females fly to the swarm in the hope of reproducing offspring, which makes the swarm a complicated ritual associated with reproduction.
Photo by michael clarke stuff CC BY-SAScientists Nicolas Wheelet (
Nicholas T. Ouelette ) and Rui Ni (
Rui Ni ) in one of their experiments recorded the sound of the buzz of a swarm, and then played it before the midges. The recorded sound influenced them unusually. With the change in sound volume (loud, quiet, loud, quiet), the area of greatest density of the midges also shifted. When only the sound of the female was reproduced through the speaker (they can be easily distinguished by the absence of antennae), the whole swarm of male midges flew in and sat down on the sound device. Scientists continue to explore the nature and mechanism of such collective behavior.
The behavior of insects and animals in complex groups (swarming, movement of schools of fish and flocks of migratory birds) has attracted scientists for decades. However, it was not until the 1980s that computer graphics specialist
Craig Reynolds developed the
boids program that simulates collective behavior in the animal kingdom. The program, by the way, was popular not only among scientists, but also in Hollywood - for example, Tim Burton used it in
Batman Returns to model groups of computer bats.
Greenland whales are versatile virtuosos of the Arctic
Greenland whales have a surprisingly diverse and ever-changing vocal repertoire. “If humpback whales songs resemble classical music, Greenland whales are jazz,”
says Kate Stafford, an oceanographer at the Applied Physics Laboratory at the University of Washington. “There is more improvisation in their sounds. Judging by the acoustic data, they have their own set of songs in each season. ” Greenland whales sing loudly, 24 hours a day, from November to April. The study was conducted using hydrophones - underwater microphones.
Photo by Olga Spak CC BY-SAThe songs of animals are not the same as calls or individual sounds. The structure of the songs is more complex - it consists of various musical phrases that require close study. Many birds and mammals use songs to identify with a group or, on the contrary, to stand out. “People are mostly visuals, but marine mammals live in three-dimensional habitats, where sound and acoustic information is what helps them navigate, find food, and socialize,” adds Stafford.
At present, little is known about singing whales in Greenland: whether the sounds are made only by males, whether individual individuals can share songs and, most importantly, why their melody changes all the time - scientists will have to answer all these questions in future studies.
Melodious mice
The little brown mouse found in the forests of Central America, like other rodents, communicates with a squeak, which is often not heard by the human ear. Male mice of the species
Scotinomys teguina sing very loudly and do it in order to attract a female.
Scientists wondered why some males of the species put more effort into singing than others. Researcher from the University of Texas Tracy Burkhard (
Tracy Burkhard ) and her team
followed the songs of mice, and then compared the level of certain hormones and nutrients in the blood of rodents. Males, who sang more and more often, had a higher concentration of
leptin , which was released in proportion to the amount of body fat in the animal.
The study showed that males can put more effort into singing if they feel enough energy in themselves, while retaining their strength to fight and flee in case of danger.
The singing mouse makes long trills — something between the sound of a cricket and a little bird. The song can last up to 20 seconds, while ordinary mice make sounds no longer than three seconds. Females of this species also sing, but males do it more often and louder.
Killer whales say hello and bye-bye
Not only parrots can imitate human speech, but also killer whales - scientists have come to this
conclusion . During the research, the 14-year-old orca was able to say such words as Amy, bye-bye, hello, imitating the trainer. Previously, she was trained to obey the “copy it” manual signal, which was initially given to her as an instruction to imitate another orca, which shoots water into the air. Then the scientists turned on the sounds she had never heard - 5 sounds of other killer whales and 6 phrases uttered by the trainers - and asked them to repeat. Killer whale responded to the command and reproduced similar sounds.
Killer whales have group differentiated vocal dialects that are supposedly acquired not genetically, but by means of familiarization with the “tradition”. Scientists believe that the killer whale's ability to imitate various sounds may be the key to studying their communication and interaction with each other.
Studying vocal imitation, dialects, sound signals and vocalizations helps scientists better understand auditory perception, reaction time and cognitive abilities of animals, and in some cases
compare their development with human evolution.
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