A. The sound of Baleen Whales is the loudest produced by any animal on earth and travels for many kilometres underwater. It may be used for long-range contact, meeting calls, in their search for mates, as a greeting, threat or individual identification. They produce mostly low-frequency sounds, which are for long distance communication, orientation and navigation. Whale communication occurs through low-frequency moans, as well as high-frequency whistles that are produced by the whales. Whales also communicate by means of body language such as slapping their tails. Whale noises such as forceful spouts of water may signal annoyance, and the slapping of flippers indicates excitement or aggression.
B. Whales use beautiful lyrical sounds called whale song to communicate with each other. As whales are so large and powerful, they make very loud sounds that can be heard for many kilometres. Whales have been known to generate about 20,000 acoustic watts of sound at 163 decibels.
C. Some whale species produce a pattern of regular and predictable whale sounds, the most notable being the Humpback Whale. It has been compared with human music, with these creatures being the ‘composers’. On the other hand, most toothed whales do not produce whale song, but instead produce rapid bursts of high-frequency clicks and whistles. Single clicks are known to be used in echolocation; however, a collection of clicks together is for communication. Male Humpback Whales make these sounds during the mating season, which suggests that the purpose of their songs is to select a mate. It is unknown whether it is also their means of defining territory or even flirting between males and females.
D. Whales occupying the same geographical location tend to sing similar whale songs, only varying them slightly. However, whales from different areas sing different songs. A study over a period of 19 years found that the same song combinations never occurred, suggesting that whales never reuse old song patterns. Whales in one area sing the same song at any point in time, a song which constantly and slowly changes over time. Over any given period, one song will start with increasing frequency but may slowly flatten to become more constant. A whale will typically repeat the same phrase of song over and over again for two to four minutes at a time. This is known as a theme, of which a collection makes a song. The whale repeats the same song, which may last up to 30 minutes and even for days at a time.
E. The mechanisms used by whales to produce sound vary from one species to another. Most whales produce whale sounds by passing air through a structure in the head called the phonic lips. The lips vibrate as the air passes through them and these vibrations can be consciously controlled with great sensitivity. They pass through to the melon of the head, which shapes and directs the sound into a beam for echolocation. The air may be recycled back to be used for sound creation yet again, or passed out through the blowhole. All toothed whales, except for the Sperm Whale, have two sets of phonic lips; therefore they are capable of making two sounds independently. Baleen Whales do not have phonic lip structures, only a larynx that appears to play a role in producing whale sound.
F. Marine creatures are largely dependent on sound for communication and sensation, as their other senses are limited due to their watery habitat. Environmentalists appear to be concerned about whales being harmed and not being able to find mates because of the increased noise levels at sea caused by ships and other sources. The Humpback Whale songs for instance are often disrupted and this causes immense panic in the group.
28 Từ Vựng Nâng Cao
- Long-range (adj) – /ˌlɒŋˈreɪndʒ/ – able to be used or effective over long distances – Tầm xa.
- Identification (n) – /aɪˌden.tɪ.fɪˈkeɪ.ʃən/ – the process of recognizing and naming someone or something – Sự nhận dạng, nhận diện.
- Low-frequency (adj) – /ˌləʊˈfriː.kwən.si/ – having a small number of waves in a particular period of time – Tần số thấp.
- Orientation (n) – /ˌɔː.ri.enˈteɪ.ʃən/ – the ability to know your position in relation to your surroundings – Sự định hướng.
- Navigation (n) – /ˌnæv.ɪˈɡeɪ.ʃən/ – the act of directing a ship, aircraft, etc., from one place to another – Sự điều hướng, định vị.
- Aggression (n) – /əˈɡreʃ.ən/ – spoken or physical behaviour that is threatening or involves harm to someone or something – Sự hung hăng, gây hấn.
- Lyrical (adj) – /ˈlɪr.ɪ.kəl/ – expressing personal thoughts and feelings in a beautiful or imaginative way – Trữ tình, giàu chất thơ.
- To generate (v) – /ˈdʒen.ə.reɪt/ – to cause something to exist; to produce – Tạo ra, phát ra.
- Acoustic (adj) – /əˈkuː.stɪk/ – relating to sound or hearing – (Thuộc về) âm thanh, âm học.
- Predictable (adj) – /prɪˈdɪk.tə.bəl/ – happening or behaving in a way that you expect – Có thể đoán trước, có quy luật.
- Notable (adj) – /ˈnəʊ.tə.bəl/ – important and deserving attention – Đáng chú ý, nổi bật.
- Bursts (n) – /bɜːsts/ – short, sudden periods of activity – Các chuỗi (âm thanh) ngắn, dồn dập.
- High-frequency (adj) – /ˌhaɪˈfriː.kwən.si/ – having a large number of waves in a particular period of time – Tần số cao.
- Echolocation (n) – /ˌek.əʊ.ləʊˈkeɪ.ʃən/ – the use of reflected sound to find objects – Định vị bằng tiếng vang.
- Territory (n) – /ˈter.ɪ.tər.i/ – an area that an animal or person treats as their own – Lãnh thổ.
- Typically (adv) – /ˈtɪp.ɪ.kəl.i/ – in a way that shows all the characteristics that you would expect from a particular group – Một cách điển hình, thường lệ.
- Theme (n) – /θiːm/ – a short, simple tune on which a piece of music is based – Một chủ đề, một đoạn (trong bài hát của cá voi).
- Mechanism (n) – /ˈmek.ə.nɪ.zəm/ – a part of a machine, or a set of parts that work together; a system for achieving a result – Cơ chế, cơ cấu.
- Phonic (adj) – /ˈfɒn.ɪk/ – relating to the sounds of spoken language – (Thuộc về) âm thanh, phát âm.
- To vibrate (v) – /vaɪˈbreɪt/ – to shake with small, rapid movements – Rung, dao động.
- Consciously (adv) – /ˈkɒn.ʃəs.li/ – in a way that is intentional and that you are aware of – Một cách có ý thức, chủ động.
- Beam (of sound) (n) – /biːm/ – a line of energy such as light, or a signal such as radio waves, sent in a particular direction – Chùm, luồng (âm thanh).
- To recycle (v) – /ˌriːˈsaɪ.kəl/ – to use something again for a new purpose – Tái sử dụng, tuần hoàn.
- Blowhole (n) – /ˈbləʊ.həʊl/ – a hole in the top of the head of a whale, through which it breathes – Lỗ phun nước.
- Independently (adv) – /ˌɪn.dɪˈpen.dənt.li/ – without being influenced or controlled by other things or people – Một cách độc lập.
- Larynx (n) – /ˈlær.ɪŋks/ – a structure in the throat containing the vocal cords – Thanh quản.
- Habitat (n) – /ˈhæb.ɪ.tæt/ – the natural environment in which an animal or plant usually lives – Môi trường sống.
- To disrupt (v) – /dɪsˈrʌpt/ – to prevent something from continuing as expected – Làm gián đoạn, phá vỡ.
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