Elephants and Sirenians: A Comparative Review across Related Taxa in Regard to Learned Vocal Behavior

Baotic, Anton; Brady, Beth; Ramos, Eric A.; Stoeger, Angela S.

doi:10.3819/ccbr.2022.170004

Cited by 2 publications

(1 citation statement)

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“…Many studies have established sound navigation and ranging (SONAR) scans as a valuable method of underwater detection of Antillean manatees (T. m. manatus) in their turbid waters of Mexico and Central America, with manatee detection frequencies of up to 93% (Gonzalez-Socoloske et al, 2009;Gonzalez-Socoloske and Olivera-Gomez, 2012;Guzman and Condit, 2017;Puc-Carrasco et al, 2017;Castelblanco-Martıńez et al, 2018). In addition, manatees produce a variety of vocalizations including squeaks, screeches, whines, and trills (Umeed et al, 2018;Brady et al, 2020;Baotic et al, 2022) shown to be important for their underwater communication and emitted across various behavioral states (Bengtson and Fitzgerald, 1985;O'Shea and Poche, 2006;Brady et al, 2021). Passive acoustics have been used in many studies to monitor manatees and have yielded up to 100% detection frequencies (LaCommare et al, 2008;Kikuchi et al, 2013;Rivera Chavarria et al, 2015;Rycyk et al, 2021;Rycyk et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Acoustic methods improve the detection of the endangered African manatee

Factheu

Rycyk²,

Kekeunou³

et al. 2023

Front. Mar. Sci.

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The African manatee (Trichechus senegalensis) is an elusive, data-deficient, and endangered species which inhabits marine and freshwater systems throughout Western and Central Africa. A major challenge in understanding the species ecology and distribution is the difficulty in detecting it using traditional visual surveys. The recent invasion of Giant Salvinia (Salvinia molesta) at the most important site for the species in Cameroon further limits their detectability and may restrict their movements and habitat use. To investigate methods’ effectiveness in detecting African manatees, we conducted monthly vessel surveys from which visual point scans, 360° sonar scans, and passive acoustic monitoring were conducted simultaneously at ten locations and over 12 months in Lake Ossa, Cameroon. Manatee detection frequency was calculated for each method and the influence of some environmental conditions on the methods’ effectiveness and manatee detection likelihood was assessed by fitting a binary logistic regression to our data. Detection frequencies were significantly different between methods (p < 0.01) with passive acoustics being the most successful (24.17%; n = 120), followed by the 360° sonar scan (11.67%; n = 120), and the visual point scan (3.33%; n = 120). The likelihood of detecting manatees in Lake Ossa was significantly influenced by water depth (p = 0.02) and transparency (p < 0.01). It was more likely to detect manatees in shallower water depths and higher water transparency. Passive acoustic detections were more effective in uninvaded areas of the Lake. We recommend using passive acoustics to enhance African manatee detections in future surveys.

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Section: Introductionmentioning

confidence: 99%

Acoustic methods improve the detection of the endangered African manatee

Factheu

Rycyk²,

Kekeunou³

et al. 2023

Front. Mar. Sci.

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Vocal usage learning and vocal comprehension learning in harbor seals

Duengen,

Jadoul,

Ravignani

2024

BMC Neurosci

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Background Which mammals show vocal learning abilities, e.g., can learn new sounds, or learn to use sounds in new contexts? Vocal usage and comprehension learning are submodules of vocal learning. Specifically, vocal usage learning is the ability to learn to use a vocalization in a new context; vocal comprehension learning is the ability to comprehend a vocalization in a new context. Among mammals, harbor seals (Phoca vitulina) are good candidates to investigate vocal learning. Here, we test whether harbor seals are capable of vocal usage and comprehension learning. Results We trained two harbor seals to (i) switch contexts from a visual to an auditory cue. In particular, the seals first produced two vocalization types in response to two hand signs; they then transitioned to producing these two vocalization types upon the presentation of two distinct sets of playbacks of their own vocalizations. We then (ii) exposed the seals to a combination of trained and novel vocalization stimuli. In a final experiment, (iii) we broadcasted only novel vocalizations of the two vocalization types to test whether seals could generalize from the trained set of stimuli to only novel items of a given vocal category. Both seals learned all tasks and took ≤ 16 sessions to succeed across all experiments. In particular, the seals showed contextual learning through switching the context from former visual to novel auditory cues, vocal matching and generalization. Finally, by responding to the played-back vocalizations with distinct vocalizations, the animals showed vocal comprehension learning. Conclusions It has been suggested that harbor seals are vocal learners; however, to date, these observations had not been confirmed in controlled experiments. Here, through three experiments, we could show that harbor seals are capable of both vocal usage and comprehension learning.

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Elephants and Sirenians: A Comparative Review across Related Taxa in Regard to Learned Vocal Behavior

Cited by 2 publications

References 107 publications

Acoustic methods improve the detection of the endangered African manatee

Acoustic methods improve the detection of the endangered African manatee

Vocal usage learning and vocal comprehension learning in harbor seals

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