Laura Kloepper

Laura Kloepper
Saint Mary's College Indiana | SMC · Biology

PhD

About

41
Publications
4,102
Reads
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301
Citations
Citations since 2017
0 Research Items
165 Citations
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2017201820192020202120222023051015202530
Introduction
Bioacoustician researching dynamics of echolocation. Creator of soundintheclassroom.org, an outreach website aimed at helping middle and high school students conduct their own quantitative bioacoustics investigations.
Skills and Expertise
Additional affiliations
August 2015 - present
Saint Mary's College
Position
  • Professor (Assistant)
June 2012 - August 2015
Brown University
Position
  • Affiliate Appointment
Description
  • Post-doctoral researcher on NSF Fellowship
June 2012 - present
University of Massachusetts Dartmouth
Position
  • Researcher
Description
  • Post-doc on NSF Fellowship

Publications

Publications (41)
Article
Full-text available
The decline of bats demands more widespread monitoring of populations for conservation and management. Current censusing methods are either prone to bias or require costly equipment. Here, we report a new method using passive acoustics to determine bat count census from overall acoustic amplitude of the emerging bat stream. We recorded the video an...
Article
Full-text available
The echolocation system of the Risso's dolphin (Grampus griseus) remains poorly studied compared to other odontocete species. In this study, echolocation signals were recorded from a stationary Risso's dolphin with an array of 16 hydrophones and the two-dimensional beam shape was explored using frequency-dependent amplitude plots. Click source para...
Conference Paper
Aiming the sonar beam directly at a potential target maximizes the detection information available to an echolocating animal. In contrast, estimating the angular location of a target relies on changes in the received echo spectrum due to the frequency dependence of the transmit beam pattern. The Fisher Information quantifies the available informati...
Article
The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar beam might be actively focused, narrowing depending on target distance. In this study, we further tested this beam focusing hypothesis in a false killer whale. Using three linear arrays of hydroph...
Conference Paper
The social media service and link aggregator reddit is one of the most popular and influential websites on the internet. Boasting 174 million unique visitors per day, a high percentage of those high school and college aged students, reddit provides the perfect audience for science outreach. One of the features of reddit is Science AMA, or Ask Me An...
Conference Paper
The sonar beamwidth of mouth-emitting echolocating bats is hypothesized to change according to mouth gape angle, with a narrowing of the beam predicted with wider mouth openings. To investigate the relationship between mouth gape angle and beam size, we recorded both the emitted sonar beam as well as the mouth opening for four bats during a target...
Conference Paper
Bats easily identify targets of interest and reject clutter in the wild. A bat's transmit and receive beampatterns are frequency dependent, so it is possible that they exploit spectral cues to distinguish on-axis targets from off-axis clutter. The frequency dependent beampattern can also be interpreted as a different lowpass filter for each an...
Conference Paper
Twitter is an effective, powerful tool for scientists looking to keep abreast of trends in their field, communicate their research, and act as public advocates of science. With a simple 140-character Tweet, a person can announce new publications, comment on current events, share photos and updates of research, connect with budding young scientists,...
Conference Paper
Full-text available
Studies have shown that echolocation signals of some odontocete species are projected in both single and sometimes vertically dual-lobed beam shapes. In this study, the echolocation beam of a Risso's dolphin (Grampus griseus) was measured from a captive individual ensonifying an underwater target. Clicks were recorded with an array of 16 hydro...
Conference Paper
Full-text available
Increasing atmospheric CO2 will cause the ocean to become more acidic with pH values predicted to be more than 0.3 units lower over the next 100 years. These lower pH values have the potential to reduce the absorption component of transmission loss associated with dissolved boron. Transmission loss effects have been well studied for deep water wher...
Article
Bats perform high-resolution echolocation by comparing temporal and spectral features of their transmitted pulses to the received echoes. In complex environments with moving prey, dynamically adapting the transmitted pulses can increase the probability of successful target representation and interception. This study further investigates the adaptiv...
Conference Paper
The big brown bat (Eptesicus fuscus) produces echolocation sounds in its larynx and emits them through its open mouth. Individual mouth-opening cycles last for about 50 ms, with the sound produced in the middle, when the mouth is approaching or reaching maximum gape angle. In previous work, the mouth gape-angle at pulse emission only weakly predict...
Conference Paper
Acoustics Today has recently launched our twitter feed, @acousticsorg. Come learn how we plan to spread the mission of Acoustics Today, promote the science of acoustics, and connect with acousticians worldwide! We will also discuss proposed upcoming social media initiatives and how you, an ASA member, can help contribute. This presentation will inc...
Conference Paper
The odontocete sound production system is complex and composed of tissues, air sacs, and a fatty melon. Previous studies suggested that the emitted sonar beam might be actively focused, narrowing depending on target distance. In this study, we further tested this beam focusing hypothesis in a false killer whale (Pseudorca crassidens) in a laborator...
Article
Full-text available
Echolocating animals adjust the transmit intensity and receive sensitivity of their sonar in order to regulate the sensation level of their echoes; this process is often termed automatic gain control. Gain control is considered not to be under the animal's cognitive control, but previous investigations studied animals ensonifying targets or hydroph...
Chapter
Echolocating bats and dolphins project sounds into their surroundings and listen to the returning echoes to detect and identify objects. These animals must assemble images to locate and classify objects while dealing with a wide variety of acoustic interference that is dependent on the acoustic medium and the amount of clutter, or the distribution...
Conference Paper
The big brown bat (Eptesicus fuscus) produces echolocation sounds in its larynx and emits them through its mouth. The bat is presumed to change the directionality of the emitted echolocation beams by modifying its mouth opening width. We analyzed infrared video sampled at 240 fps synchronized to ultrasonic recordings from a Knowles Electret microph...
Conference Paper
The big brown bat, Eptesicus fuscus, uses echolocation for foraging and orientation. Bats can change the echolocation calls dependent on the environments. Therefore, it is necessary to clarify the changes of acoustic characteristics of these calls. In this study, the flight path of the bat were tracked by computing the time differences of arrivals...
Conference Paper
The echolocating big brown bat, Eptesicus fuscus, must both avoid background objects that it may collide with such as vegetation or clutter, and identify insect prey targets. When bats fly through clutter, they emit groups of echolocation sounds in rapid succession called strobe groups. Here, we investigate the limitations of strobe grouping for fl...
Article
Measurements of the transmit beam patterns emitted by echolocating bats have previously been limited to cross-sectional planes or averaged over multiple signals using sparse microphone arrays. To date, no high-resolution measurements of individual bat transmit beams have been reported in the literature. Recent studies indicate that bats may change...
Conference Paper
While flying in dense clutter or close to objects, bats often produce "strobe groups," pairs of pulses emitted at short pulse intervals followed by longer pulse intervals. Previous studies of free-flying bats demonstrate relatively consistent trends in strobe groups depending on the degree of clutter. To investigate strobe group production in stati...
Conference Paper
Although termed "automatic gain control," previous field and laboratory investigations into source level distance compensation in bats and odontocetes have relied on animals echolocating targets or arrays at predictable distances. To test the "automatic" nature of gain control in the bottlenose dolphin, the source level distance compensation was me...
Conference Paper
Echolocating bats use their active sonar to locate, discriminate, and capture flying prey. A special challenge is tracking and pursuing a discrete moving object, sometimes in cluttered surroundings. Bats rely on head aim to follow their prey's location throughout an entire capture sequence. By directing the sound emission organ (mouth or noseleaf)...
Article
Full-text available
A two-dimensional array of 16 hydrophones was created to map the spatial distribution of different frequencies within the echolocation beam of a Tursiops truncatus and a Pseudorca crassidens. It was previously shown that both the Tursiops and Pseudorca only paid attention to frequencies between 29 and 42 kHz while echolocating. Both individuals tig...
Article
Full-text available
Some odontocetes and bats vary both click intensity and receiver sensitivity during echolocation, depending on target range. It is not known how this so-called automatic gain control is regulated by the animal. The source level of consecutive echolocation clicks from a harbour porpoise was measured with a hydrophone array while the animal detected...
Article
Full-text available
The odontocete sound production system is highly complex and produces intense, directional signals that are thought to be focused by the melon and the air sacs. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation beam shape, investigations of beam focusing must account for frequency-...
Conference Paper
Measurements of the transmit beam patterns in bats have previously been limited to a single cross-sectional plane or averaged over multiple in-flight approaches with sparse microphone arrays. No high-resolution measurements have been published to date of individual transmitted beams jointly in azimuth and elevation. Toward this goal, a high density...
Conference Paper
Odontocete echolocation signals are thought to be focused by the melon and air sacs, although active focusing has yet to be demonstrated empirically. Because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation beam shape, investigations of beam focusing must account for frequency-related bea...
Article
The improvement in tagging technology and passive listening devices has allowed researchers to measure the echolocation clicks of many species of free-ranging odontocetes. Although the data collected by these instruments provide valuable information on the clicks these animals produce, these tags cannot provide information on the hearing abilities...
Article
The hearing of marine mammals has been extensively studied in the last decades and has focused primarily on species available in captivity such as the bottlenose dolphin Tursiops truncatus. Recent work has shown that mass stranding events could be related to anthropogenic sound exposure such as naval sonar activities, seismic surveys, or oil drilli...
Article
Recent studies indicate some odontocetes may produce echolocation beams with a dual-lobed vertical structure. The shape of the odontocete echolocation beam was further investigated in a false killer whale performing an echolocation discrimination task. Clicks were recorded with an array of 16 hydrophones and frequency-dependent amplitude plots were...
Article
The auditory filter shape of delphinid odontocetes was previously considered to be typically mammalian constant-quality in which filter bandwidths increase proportionally with frequency. Recent studies with porpoises demonstrate constant-bandwidth portions of the auditory filter. The critical ratios for a bottlenose dolphin were measured between 40...
Article
A 2D array of hydrophones was created to determine the spatial distribution of frequencies within the echolocation beam of a Tursiops truncatus. This Tursiops was shown previously to only pay attention to frequencies between 29 and 42 kHz while echolocating. It was found that the 30 kHz frequency was tightly focused, and the spatial location of the...
Article
High‐frequency hearing loss has been correlated with a reduction both in echolocation click parameters and in echolocation discrimination abilities in a false killer whale. During a 15‐year time period, the whale demonstrated a significant decrease in peak frequency, center frequency, and source level of outgoing clicks between two studies. Echoloc...
Article
Full-text available
Toothed whales and dolphins possess a hypertrophied auditory system that allows for the production and hearing of ultrasonic signals. Although the fossil record provides information on the evolution of the auditory structures found in extant odontocetes, it cannot provide information on the evolutionary pressures leading to the hypertrophied audito...
Article
The echolocation signals of a false killer whale (Pseudorca crassidens) were collected during a wall thickness discrimination task and compared to clicks recorded during an identical experiment in 1992. During the sixteen year time period, the subject demonstrated a loss of high frequency hearing of about 70 kHz. Clicks between the two experiments...
Article
Full-text available
Long-finned pilot whales are highly social odontocetes found in temperate and subpolar regions. This species is particularly known for its interaction with fisheries as well as its mass strandings. Recent tagging work has provided some information about pilot whales in the wild but, even though they have been successfully kept in captivity, little...
Conference Paper
Tremendous variation in individual echolocation click parameters has been shown for odontocetes, making trend analysis of individual clicks within a click train necessary to understand their generalized echolocation behavior. The frequency dependent spatial echolocation beam profile of clicks for a single false killer whale (Pseudorca crassidens) p...

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