Audiogram and auditory critical ratios of two Florida manatees (Trichechus manatus latirostris)

  title={Audiogram and auditory critical ratios of two Florida manatees (Trichechus manatus latirostris)},
  author={Joseph Gaspard and Gordon B Bauer and Roger Reep and Kimberly Dziuk and Adrienne Cardwell and Latoshia Read and David A. Mann},
  journal={Journal of Experimental Biology},
  pages={1442 - 1447}
SUMMARY Manatees inhabit turbid, shallow-water environments and have been shown to have poor visual acuity. Previous studies on hearing have demonstrated that manatees possess good hearing and sound localization abilities. The goals of this research were to determine the hearing abilities of two captive subjects and measure critical ratios to understand the capacity of manatees to detect tonal signals, such as manatee vocalizations, in the presence of noise. This study was also undertaken to… 
The influence of age and sex on the vocal repertoire of the Antillean manatee (Trichechus manatus manatus) and their responses to call playback
The acoustic signals of 15 Antillean manatees in captivity were recorded to describe their acoustic repertoire, investigate the influence of sex and age on vocalization, and examine manatee responses to call playback.
CMS Family Guidelines on Environmental Impact Assessment for Marine Noise-generating Activities
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The relationship between acoustic habitat, hearing and tonal vocalizations in the Antillean manatee (Trichechus manatus manatus, Linnaeus, 1758)
It is concluded that frequency transmission depends mainly on river depth and bottom characteristics, also motorboat sounds mask signals from 3.5  kHz to 8 kHz, which overlaps the peak frequency of tonal calls, and manatees utilize bands that transmit efficiently in all subhabitats.
The influence of variations in background noise on Florida manatee (Trichechus manatus latirostris) detection of boat noise and vocalizations
A manatee’s primary modality to detect a vessel on a possible collision course is hearing as underwater visibility is limited in many manatee habitats and their visual acuity is poor. We estimate a
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A shadowing-effect produced by the body may explain the relatively low occurrence of front-back confusions in the localization study.
The Role of Backreef Soundscapes and their Spatial Structure for Recruitment of Tropical Marine Larvae
Review of sensory modalities of sirenians and the other extant Paenungulata clade
Manatees have a higher frequency range for hearing than elephants, who have the best low‐frequency hearing range known to mammals, while the hearing range of hyraxes is unknown, and all paenungulates have vibrissae assisting in tactile abilities such as feeding and navigating the environment and share relatively small eyes and dichromatic vision.
The Relevance of Ecological Transitions to Intelligence in Marine Mammals
It would still be prudent to follow Macphail’s caution that it is premature to make strong comparative statements without more empirical evidence, but an approach that includes learning more about how animals flexibly link information across multiple representations could be a productive way of comparing species by allowing them to use their specific strengths within comparative tasks.
Gentoo penguins (Pygoscelis papua) react to underwater sounds
The fact that penguin can detect and react to underwater stimuli may indicate that they make use of sound stimuli for orientation and prey detection during dives, and suggests that penguins may be sensitive to anthropogenic noise, like many species of marine mammals.
The Antillean manatee produces broadband vocalizations with ultrasonic frequencies.
Spectral analysis revealed broadband vocalizations with frequencies up to 150 kHz and a high proportion of calls with ultrasonic components, which may be important to manatee communication.


The underwater audiogram of the West Indian manatee (Trichechus manatus).
This is the first behavioral audiogram measured for any Sirenian, as well as the first underwater infrasonic psychometric test with a marine mammal, and demonstrates a wider range of hearing and greater sensitivity than was suggested from evoked potential and anatomical studies.
Hearing in Vertebrates: A Psychophysics Databook
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All major hard and soft tissues of the peripheral auditory system of T. manatus are described, new information on specialized cranial features that may be important for sound conduction are presented, and morphometrybased estimates of the frequency range and sensitivity of West Indian manatee ears are provided.
Fourchoice sound localization abilities of two Florida manatees, Trichechus manatus latirostris
  • J. Exp. Biol. 212, 2105-2112.
  • 2009
Auditory temporal resolution of the manatee (Trichechus manatus latirostris) auditory system
  • J. Comp. Physiol. A 191, 903-908.
  • 2005
Temporal resolution of the Florida manatee (Trichechus manatus latirostris) auditory system
Auditory evoked potential measurements of two Florida manatees were measured in response to amplitude modulated tones, and Audiograms estimated from the input–output functions of the EPs greatly underestimate behavioral hearing thresholds measured in two otherManatees.
Four-choice sound localization abilities of two Florida manatees, Trichechus manatus latirostris
It is demonstrated that manatees are able to localize frequency bands with wavelengths that are both shorter and longer than their interaural time distances and suggested that they have the ability to localized both manatee vocalizations and recreational boat engine noises.
Behavioral Methodology in Echolocation by Marine Mammals
Despite the fact that a preponderance of the investigations dealing with echolocation by marine mammals has been done with intact animals performing some characteristic behavior, only a single paper
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Masked thresholds were obtained by the method of behavioral audiometry fur each of four cats at eleven frequencies over the range from 125 to 16 000 cps. Bands of noise, which were approximately one
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