Bioacoustics 610760 224993540 2008-07-11T10:44:24Z 129.125.47.193 /* External links */ '''Bioacoustics''' is a cross-disciplinary [[science]] that combines [[biology]] and [[acoustics]]. Usually it refers to the investigation of [[sound]] production, dispersion through elastic [[medium|media]], and reception in [[animals]], including [[humans]]. This involves [[neurophysiology|neurophysiological]] and [[anatomy|anatomical]] basis of sound production and detection, and relation of acoustic [[signal]]s to the [[medium]] they disperse through. The findings give us some evidence about the [[evolution]] of acoustic mechanisms, and from that, the evolution of animals that employ them. In [[underwater acoustics]] and fisheries acoustics the term is also used to mean the effect of [[plants]] and animals on sound propagated underwater, usually in reference to the use of [[sonar]] technology for [[biomass]] estimation<ref>Medwin H. & Clay C.S. (1998). ''Fundamentals of Acoustical Oceanography'', [[Academic Press]]</ref><ref name="SimmondsMacLennan">Simmonds J. & MacLennan D. (2005). ''Fisheries Acoustics: Theory and Practice'', second edition. [[Blackwell]]</ref> ==History== Man has for a long time employed animal sounds to recognise and find them. Bioacoustics as a [[scientific discipline]] was established by the [[Slovenians|Slovenian]] biologist [[Ivan Regen]]. On [[31 August]] [[1925]] he used a special [[stridulation|stridulatory]] device to play in a duet with an [[insect]]. Later he put a male [[cricket]] behind a microphone and female crickets in front of a loudspeaker. The females were not moving towards the male but towards the loudspeaker.<ref>Kočar T. (2004). ''[http://www.gea-on.net/clanek.asp?ID=522 Kot listja in kobilic]'' (''As many as leaves and grasshoppers''). [[GEA (magazine)|GEA]], october 2004. [[Mladinska knjiga]], [[Ljubljana]] {{sl icon}}</ref> The most recent advances in bioacoustics concern the relationships among the animals and their environment and the impact of anthropogenic [[Noise (environmental)|noise]]. ==Methods in bioacoustics== [[Image:Underwater-microphone hg.jpg|thumb|80px|right|Hydrophone]] Listening is still one of the main methods used in bioacoustical research. Little is known about neuropyhsiological processes that play a role in production, detection and interpretation of sounds in animals, so [[animal behaviour]] and the signals themselves are used for gaining insight into these processes. ===Acoustic signals=== [[Image:Akhumps 128 016 0 500c.gif|thumb|200px|left|[[Spectrogram]] (above) and [[oscillogram]] (below) of the [[humpback whale]]'s calls]] An experienced observer can use animal sounds to recognize a "singing" animal [[species (biology)|species]], its location and condition in nature. Investigation of animal sounds also includes signal recording with electronic recording equipment. Due to the wide range of signal properties and media they propagate through, specialized equipment may be required instead of the usual [[microphone]]s, such as [[hydrophone]] (underwater sounds), [[ultrasound]] detector (very high-[[frequency]] sounds), or [[laser]] [[vibrometer]] (substrate-borne vibrational signals). [[Computer]]s are used for storing and analysis of recorded sounds. Specialized sound-editing [[software]] is used for describing and sorting signals according to their [[intensity]], [[frequency]], duration and other parameters. Animal sound collections, managed by [[museum of natural history|museums of natural history]] and other institutions, are an important tool for systematic investigation of signals. ===Sound production, detection, and use in animals=== [[Scientist]]s in the field of bioacoustics are interested in anatomy and neurophysiology of [[organ (anatomy)|organs]] involved in sound production and detection, including their shape, [[muscle]] action, and activity of [[neuronal network]]s involved. Of special interest is coding of signals with [[action potential]]s in the latter. But since the methods used for neurophysiological research are still fairly complex and understanding of relevant processes is incomplete, more trivial methods are also used. Especially useful is observation of behavioural responses to acoustic signals. One of such is [[phonotaxy]] - directional movement towards the signal source. By observing response to well defined signals in controlled environment, we can gain insight into signal function, [[sensitivity]] of the hearing apparatus, [[noise]] filtering capability, etc. ===Biomass estimation=== Biomass estimation uses [[sonar]] to detect [[fish]], etc.<ref name="SimmondsMacLennan"/> As the sound pulse travels through water it encounters objects that are of different density than the surrounding medium, such as fish, that reflect sound back toward the sound source. These echoes provide information on fish size, location, and [[abundance (ecology)|abundance]]. The basic components of the scientific [[echo sounder]] [[hardware]] function is to transmit the sound, receive, filter and amplify, record, and analyze the echoes. While there are many manufacturers of commercially available »fish-finders«, quantitative analysis requires that measurements be made with [[calibration|calibrated]] echo sounder equipment, having high [[signal-to-noise ratio]]s. ==Animal sounds== [[Image:Birdsinging03182006.JPG|thumb|right|200px|[[European starling]] singing]] Sounds used by animals that fall within the scope of bioacoustics include a wide range of frequencies and media, and are often not sound in the strict sense of the word, i.e. [[compression wave]]s that propagate through [[air]] and are detectable by the human [[ear]]. [[Katydid]] [[cricket]]s, for example, communicate by sounds with frequencies higher than 100 [[Hertz|kHz]], far into the ultrasound range.<ref>Mason A.C., Morris G.K., Wall P. (1991): ''High Ultrasonic Hearing and Tympanal Slit Function in Rainforest Katydids''. Naturwissenschaften '''78''': 365-367.</ref> Lower, but still in ultrasound, are sounds used by [[bat]]s for [[echolocation]]. On the other side of the frequency spectrum are low frequency-vibrations, often not detected by [[Hearing (sense)|hearing]] organs, but with other, less specialized sense organs. The examples include ground vibrations produced by [[elephants]] whose principal frequency component is around 15 Hz, and low- to medium-frequency substrate-borne vibrations used by most [[insect]] [[order (biology)|orders]]<ref>Virant-Doberlet M. & Čokl A. (2004): ''Vibrational communication in insects''. Neotropical Entomology '''33'''(2): 121-134</ref>. Many animal sounds, however, do fall within the frequency range detectable by a human ear, between 50 and 15,000 Hz. Mechanisms for sound production and detection are just as diverse as the signals themselves. ==See also== * [[Acoustic ecology]] * [[Acoustical oceanography]] * [[Animal communication]] * [[Animal language]] * [[Biomusic]] * [[Field recording]] * [[Natural sounds]] * [[Sonar]] * [[Underwater acoustics]] * [[Vocal learning]] * [[Whale song]] * [[Zoomusicology]] ==External links== *[http://www.marine.usf.edu/bio/fishlab/research.htm Marine Bioacoustics Centre] of the University of South Florida. Has fish sound recordings. *[http://www.lab.upc.es/ Laboratory of Applied Bioacoustics] *[http://www.bl.uk/collections/sound-archive/wild.html The British Library Sound Archive] has 150,000 recordings of over 10,000 species. *[http://www.ibac.info/ International Bioacoustics Council] links to many bioacoustics resources. *[http://blb.biosci.ohio-state.edu/ Borror Laboratory of Bioacoustics] at The Ohio State University has a large archive of animal sound recordings. * [http://www.bl.uk/listentonature Listen to Nature] 400 examples of animal songs and calls * [http://www.wildlife-sound.org/ Wildlife Sound Recording Society] * [http://www.xeno-canto.org xeno canto :: songs and calls of over 4000 bird species from the Americas, Africa and Asia on-line] * [http://beamreach.org Beam Reach Marine Science and Sustainability School] Killer whale sounds, some localized using hydrophone arrays * [http://www.birds.cornell.edu/brp/?lk=lpro/ Bioacoustic Research Program] at the [[Cornell Lab of Ornithology]] distributes a number of different free bioacoustics synthesis & analysis programs. * [http://www.birds.cornell.edu/macaulaylibrary/?lk=lpro Macaulay Library] at the [[Cornell Lab of Ornithology]] is the world's largest collection of animal sounds and associated video. *[http://www.avisoft.com/ Avisoft Bioacoustics] provides various hardware and software solutions for bioacoustic research. ==References== {{reflist}} ==Further reading== * Ewing A.W. (1989): ''Arthropod bioacoustics: Neurobiology and behaviour''. Edinburgh: Edinburgh Universitsy Press. ISBN 0-7486-0148-1 * Fletcher N. (2007): ''[http://www.springer.com/cda/content/document/cda_downloaddocument/sample%20chapter.pdf?SGWID=0-0-45-279393-p123153395 Animal Bioacoustics]''. IN: Rossing T.D. (ed.): ''[http://www.springer.com/east/home/generic/search/results?SGWID=5-40109-22-153743469-0 Springer Handbook of Acoustics]'', [[Springer Science+Business Media|Springer]]. ISBN 978-0-387-33633-6 {{animal language}} [[Category:Acoustics]] [[Category:Zoosemiotics]] [[el:Βιοακουστική]] [[pl:Bioakustyka]] [[pt:Bioacústica]] [[sl:Bioakustika]]