@article {58401,
	title = {Allometric escape and acoustic signal features facilitate high-frequency communication in an endemic Chinese primate},
	year = {2021},
	abstract = {<p>The principle of acoustic allometry\&mdash;the larger the animal, the lower its calls\&$\#$39; fundamental frequency\&mdash;is generally observed across terrestrial mammals. Moreover, according to the Acoustic Adaptation Hypothesis, open habitats favor the propagation of high-frequency calls compared to habitats with complex vegetational structures. We carried out playback experiments in which the calls of the Guizhou snub-nosed monkey (Rhinopithecus brelichi) were used as stimuli in sound attenuation and degradation experiments to test the hypothesis that propagation of Guizhou snub-nosed monkey calls is favored above vs through the forest floor vegetation. We found that low-pitched Guizhou snub-nosed monkey vocalizations suffered less attenuation than its high-pitched calls. Guizhou snub-nosed monkeys were observed emitting high-pitched calls from 1.5 to 5.0 m above the ground. The use of high-pitched calls from these heights coupled with the concomitant behavior of moving about above the understory may provide a signal for receivers which maximizes potential transmission and efficacy. Our results support the Acoustic Adaptation Hypothesis and suggest that by uncoupling its vocal output from its size, this monkey can produce a high-pitched call with a broad spectral bandwidth, thereby increasing both its saliency and the frequency range over which the animal may more effectively communicate in its natural habitat.</p>
},
	keywords = {acoustic adaptation hypothesis, Principle of acoustic allometry, Rhinopithecus brelichi, Snub-nosed monkey, Sound propagation},
	doi = {10.1007/s00359-021-01465-7},
	url = {http://link.springer.com/10.1007/s00359-021-01465-7},
	author = {Riondato, Isidoro and Gamba, Marco and Tan, Chia L. and Niu, Kefeng and Narins, Peter M. and Yang, Yeqin and Giacoma, Cristina}
}
@article {53066,
	title = {Call and be counted! Can we reliably estimate the number of callers in the indri{\textquoteright}s (Indri indri) song?},
	journal = {PLOS ONE},
	volume = {13},
	year = {2018},
	month = {Mar-08-2018},
	pages = {e0201664},
	abstract = {<p>Estimating the number of animals participating in a choral display may contribute reliable information on animal population estimates, particularly when environmental or behavioral factors restrict the possibility of visual surveys. Difficulties in providing a reliable estimate of the number of singers in a chorus are many (e.g., background noise masking, overlap). In this work, we contributed data on the vocal chorusing of the indri lemurs (Indri indri), which emit howling cries, known as songs, uttered by two to five individuals. We examined whether we could estimate the number of emitters in a chorus by screening the fundamental frequency in the spectrograms and the total duration of the songs, and the reliability of those methods when compared to the real chorus size. The spectrographic investigation appears to provide reliable information on the number of animals participating in the chorusing only when this number is limited to two or three singers. We also found that the Acoustic Complexity Index positively correlated with the real chorus size, showing that an automated analysis of the chorus may provide information about the number of singers. We can state that song duration shows a correlation with the number of emitters but also shows a remarkable variation that remains unexplained. The accuracy of the estimates can reflect the high variability in chorus size, which could be affected by group composition, season and context. In future research, a greater focus on analyzing frequency change occurring during these collective vocal displays should improve our ability to detect individuals and allow a finer tuning of the acoustic methods that may serve for monitoring chorusing mammals.</p>
},
	doi = {10.1371/journal.pone.0201664},
	url = {http://dx.plos.org/10.1371/journal.pone.0201664},
	author = {Torti, Valeria and Valente, Daria and De Gregorio, Chiara and Comazzi, Carlo and Miaretsoa, Longondraza and Ratsimbazafy, Jonah and Giacoma, Cristina and Gamba, Marco},
	editor = {Reby, David}
}
