Bioacoustics - Wikiparency

# Bioacoustics ## Overview Study of animal communication and biological sound production. ## Acoustics bridge Herd health by ear, grain-bin level by echo ## Hub connections ### Engineering Center of Excellence Secondary acoustic application context (to be developed). ### Advanced Manufacturing Center of Excellence Secondary acoustic application context (to be developed). ### Transportation Center of Excellence Secondary acoustic application context (to be developed). ### Energy Center of Excellence Secondary acoustic application context (to be developed). ### IT Center of Excellence Secondary acoustic application context (to be developed). ### HealthForce Center of Excellence Secondary acoustic application context (to be developed). ### Northern Agricultural Center of Excellence (primary) This article bridges [[PORTAL_Acoustics]] to the [[WT!Northern_Agricultural_Center_of_Excellence]]. The acoustic signature of bioacoustics is central to northern agricultural operations. ### Southern Agricultural Center of Excellence Secondary acoustic application context (to be developed). ### Space Mining In Minnesota — Center Circle Secondary acoustic application context (to be developed). --- *Bridge article, scaffolded from [[PORTAL_Acoustics]]. Minimal content; awaiting expansion.* ## History Bioacoustics grew out of two older habits of listening: naturalists transcribing birdsong and animal calls by ear, and physicists and engineers building instruments — the phonograph, then the microphone and oscillograph — that could record and measure a sound instead of only describing it. Underwater listening for military purposes during and after the First and Second World Wars produced hydrophones sensitive enough to record whale and fish sounds, and the sound spectrograph, developed at Bell Telephone Laboratories in the 1940s, gave researchers a way to see a call's frequency content over time rather than only hear it, turning bird and animal sounds into a visual record that could be measured, compared and archived. Peter Marler's studies of bird dialects and Roger Payne and Scott McVay's 1971 identification of repeating, patterned song in humpback whales are among the field's founding results, the latter turning whale sound from a curiosity into a subject with its own grammar of study.[^payne1971] ## Importance Bioacoustics matters because sound is often the most practical channel for observing animals that are hard to see: nocturnal, underwater, underground, airborne at night, or simply too shy or too numerous to count visually. A recording captures behavior — territorial defense, mate attraction, alarm, echolocation — without disturbing the animal enough to change it, and a fixed recorder can listen continuously for weeks where a human observer cannot. The same tools serve conservation and land management directly: passive acoustic monitoring can establish which species are present at a site and how their calling activity changes with season, weather or disturbance, at a fraction of the cost of repeated field surveys. ## Methods ### Acoustic signals An animal sound is described by the same quantities that describe any acoustic signal: fundamental frequency and its harmonics, duration, amplitude envelope, and how frequency changes over time (a frequency-modulated sweep, as in many bat calls, versus a nearly constant tone). The spectrogram — a plot of frequency against time with amplitude shown as intensity or color — is the field's standard way of displaying a call, because it shows structure (chirps, pulses, syllables, harmonics) that a plot of pressure against time alone does not make obvious. ### Sound production, detection, and use in animals Animals produce sound by a wide range of mechanisms: vocal folds and air sacs in mammals and birds, stridulation (rubbing body parts together) in many insects, drumming or percussion against a substrate, and, in echolocating bats and toothed whales, specialized structures — the larynx or, in toothed whales, phonic lips and the melon — built to produce short, precisely timed, often ultrasonic pulses. Detection is equally varied: ears tuned to a species' own call frequencies, lateral lines and swim bladders in fish that sense pressure changes in water, and, in echolocating animals, an auditory system fast enough to time an echo's return to within microseconds. Sound in animals serves communication (territorial calls, mate attraction, alarm calls, parent-offspring contact), and, in bats, toothed whales and a small number of birds (oilbirds and some swiftlets), active sensing by echolocation — see [[Animal_echolocation|animal echolocation]] — in which the animal produces a call and reads its own echo to build a picture of range, size, texture and motion of objects around it. *Try: in the microsim, switch call type between FM and CF to compare the bat's two echolocation strategies — an FM sweep from 80 to 40 kHz resolves range precisely from its echo delay, while a constant-frequency call resolves the Doppler shift of a moving target instead; slide moth speed toward the bat and watch the echo's frequency shift.* ### Biomass estimation Because many species call at a rate that correlates with their local abundance, recorded call rate is used as one input to estimating the biomass or population density of a site — most developed for fish choruses, insect and amphibian choruses, and bird dawn choruses — though the relationship between calling rate and true abundance depends on species behavior and must be calibrated against independent counts rather than assumed universal. ### AI detection Automated classifiers, increasingly built on machine-learning models trained on large labeled call libraries, now do much of the work of finding and identifying calls in the enormous volume of audio a continuous recorder produces, work that was previously done by a human scanning spectrograms by eye. These classifiers let a single research group process recordings from dozens of sites and years of continuous listening, and they are a major reason passive acoustic monitoring has expanded from a specialist technique into a standard conservation tool. ## Animal sounds Animal sound spans roughly ten octaves once ultrasound and infrasound are included: from the roughly 14–35 Hz content of an elephant's rumble, at the edge of and below human hearing, to the ultrasonic clicks and FM sweeps of bats and toothed whales that reach well above 100 kHz.[^up17-2] Birdsong, insect stridulation, frog and toad chorusing, and the clicks, whistles and pulsed calls of marine mammals are the most intensively studied categories, each with its own repertoire of species-specific structure that bioacousticians use for species identification, individual recognition and behavioral study. ## Plant sounds A newer line of bioacoustics research investigates sounds produced by plants themselves, and by the water columns inside them, rather than only sounds that affect plants. Cavitation events — the sudden formation and collapse of air bubbles in a plant's water-transport tissue under drought stress — produce ultrasonic clicks that have been recorded and used as an indicator of water stress; more speculative work has reported airborne clicks from stressed plants detectable by nearby insects or other organisms, an active and still-developing area rather than a settled result. *Citation needed* for a specific verified figure on click rate or amplitude in this subfield. ## Minnesota *This section is specific to Wikitube.* No specific sourced Minnesota bioacoustics program is confirmed for this article. *Citation needed* if a Minnesota grain-elevator or dairy-herd acoustic monitoring program, of the kind gestured at in the "Acoustics bridge" note above, should be named here with a primary source. ## See also - [[Heart_sounds]] - [[Otoacoustic_emission]] - [[Animal_echolocation]] - [[Sound]] - [[Doppler_effect]] ## References [^payne1971]: Payne, Roger S.; McVay, Scott (1971). "Songs of humpback whales." *Science* 173 (3997), 585–597. https://doi.org/10.1126/science.173.3997.585 [^up17-2]: OpenStax, *University Physics Volume 1* (2016), ch. 17.2 "Speed of Sound," Figure 17.6 (a bat uses sound echoes to find its way about and to catch prey; the echo time is directly proportional to distance) and ch. 17.7 "The Doppler Effect."  **Microsim — three.js (Wikitube framework):** *Bioacoustics* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/acoustics/Bioacoustics.html" data-title="Bioacoustics"></div> *Built from `MICROSIM_GUIDE/specs/acoustics/sims/Bioacoustics.json`; part of the [[PORTAL_Acoustics|Acoustics portal]] spine (section sims and See-also variants).*  ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Bioacoustics) : [Wikitube](https://en.wikitube.io/wiki/Bioacoustics) - skeleton pinned to revision 1360619283 (2026-09-11).