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Structure and variability of bat social calls: implications for specificity and individual recognition
- J Zool
, 2003
"... Communication sounds or ‘social calls ’ of 16 European bat species (Chiroptera, Vespertilionidae) were recorded at a range of roost and foraging sites. A comparative analysis of more than 5400 individual calls for general structures and for inter- as well as intraspecific variability resulted in 50 ..."
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Communication sounds or ‘social calls ’ of 16 European bat species (Chiroptera, Vespertilionidae) were recorded at a range of roost and foraging sites. A comparative analysis of more than 5400 individual calls for general structures and for inter- as well as intraspecific variability resulted in 50 types of calls, which differed by their specific structure and by the calling species. These types could be grouped into four different general types of calls, according to the kind and complexity of their structure, independent of the calling species. Distinct types of calls seem to have similar functions in different bat species. One general type may be used predominantly in female–infant interactions as an isolation or direction call, which serves as mutual recognition. This type of social call was also used in ‘tandem flights ’ of pairs of bats, which might increase individual knowledge of roost sites and foraging success. A second type was used in mate attraction, and a further one in an aggressive context. The fourth one was used by hindered or distressed bats. The group of ‘aggressive ’ calls is least variable, but the complex mating calls and isolation calls are very diverse. Species-specific sound structures were identified, which allowed a computational species distinction. The measured inter-individual variability of social calls should be significant for their functions in individual recognition. So, beyond common features concerning the frequency structure of bat social calls, interspecific differences, as well as the intraspecific variability of details of sonagraphic parameters, should elucidate the specific functions of the calls. Key words: bats, Chiroptera, communication, individual recognition, social calls
Teeling E C. The evolution of echolocation in bats
- Trends Ecol. Evol
, 2006
"... Recent molecular phylogenies have changed our perspective on the evolution of echolocation in bats. These phylogenies suggest that certain bats with sophisticated echolocation (e.g. horseshoe bats) share a common ancestry with non-echolocating bats (e.g. Old World fruit bats). One interpretation of ..."
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Recent molecular phylogenies have changed our perspective on the evolution of echolocation in bats. These phylogenies suggest that certain bats with sophisticated echolocation (e.g. horseshoe bats) share a common ancestry with non-echolocating bats (e.g. Old World fruit bats). One interpretation of these trees presumes that laryngeal echolocation (calls produced in the larynx) probably evolved in the ancestor of all extant bats. Echolocation might have subsequently been lost in Old World fruit bats, only to evolve secondarily (by tongue clicking) in this family. Remarkable acoustic features such as Doppler shift compensation, whispering echolocation and nasal emission of sound each show multiple convergent origins in bats. The extensive adaptive radiation in echolocation call design is shaped largely by ecology, showing how perceptual challenges imposed by the environment can often override phylogenetic constraints. Echolocation and the diversity of bats Bats are perhaps the most unusual and specialized of all mammals. Together with birds, they are the only extant vertebrates that are capable of powered flight. Bats have mastered the night skies largely by using echolocation (biosonar) to perceive their surroundings
Dynamics of jamming avoidance in echolocating bats
, 2004
"... Animals using active sensing systems such as echolocation or electrolocation may experience interference from the signals of neighbouring conspecifics, which can be offset by a jamming avoidance response (JAR). Here, we report JAR in one echolocating bat (Tadarida teniotis: Molossidae) but not in an ..."
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Animals using active sensing systems such as echolocation or electrolocation may experience interference from the signals of neighbouring conspecifics, which can be offset by a jamming avoidance response (JAR). Here, we report JAR in one echolocating bat (Tadarida teniotis: Molossidae) but not in another (Taphozous perforatus: Emballonuridae) when both flew and foraged with conspecifics. In T. teniotis, JAR consisted of shifts in the dominant frequencies of echolocation calls, enhancing differences among individuals. Larger spectral overlap of signals elicited stronger JAR. Tadarida teniotis showed two types of JAR: (i) for distant conspecifics: a symmetric JAR, with lower- and higher-frequency bats shifting their frequencies downwards and upwards, respectively, on average by the same amount; and (ii) for closer conspecifics: an asymmetric JAR, with only the upper-frequency bat shifting its frequency upwards. In comparison, ‘wave-type ’ weakly electric fishes also shift frequencies of discharges in a JAR, but unlike T. teniotis, the shifts are either symmetric in some species or asymmetric in others. We hypothesize that symmetric JAR in T. teniotis serves to avoid jamming and improve echolocation, whereas asymmetric JAR may aid com-munication by helping to identify and locate conspecifics, thus minimizing chances of mid-air collisions.
Article Classification of Echolocation Calls from 14 Species of Bat by Support Vector Machines and Ensembles of Neural Networks
"... Abstract: Calls from 14 species of bat were classified to genus and species using discriminant function analysis (DFA), support vector machines (SVM) and ensembles of neural networks (ENN). Both SVMs and ENNs outperformed DFA for every species while ENNs (mean identification rate – 97%) consistently ..."
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Abstract: Calls from 14 species of bat were classified to genus and species using discriminant function analysis (DFA), support vector machines (SVM) and ensembles of neural networks (ENN). Both SVMs and ENNs outperformed DFA for every species while ENNs (mean identification rate – 97%) consistently outperformed SVMs (mean identification rate – 87%). Correct classification rates produced by the ENNs varied from 91 % to 100%; calls from six species were correctly identified with 100 % accuracy. Calls from the five species of Myotis, a genus whose species are considered difficult to distinguish acoustically, had correct identification rates that varied from 91 – 100%. Five parameters were most important for classifying calls correctly while seven others contributed little to classification performance.
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"... Ten species of bats occur in the Oregon Coast Range and are hypothesized to be associated with late-successional forests. The development of characteristics of late-successional forests in young forest stands can be accelerated through silvicultural practices such as thinning I examined the effects ..."
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Ten species of bats occur in the Oregon Coast Range and are hypothesized to be associated with late-successional forests. The development of characteristics of late-successional forests in young forest stands can be accelerated through silvicultural practices such as thinning I examined the effects of thinning on the use of forests by bats in the Oregon Coast Range. I used automated ultrasonic detectors to record bat calls in 50- to 100-year-old thinned and =thinned stands as well as in old-growth (2200- year-old) stands in 11 sites in the Oregon Coast Range during the summers of 1994 and 1995. I compared bat activity levels among the 3 stand types. In addition, I classified bat calls into
3348 The Journal of Experimental Biology 213, 3348-3356 © 2010. Published by The Company of Biologists Ltd
, 2010
"... doi:10.1242/jeb.044818 Effects of competitive prey capture on flight behavior and sonar beam pattern in paired big brown bats, Eptesicus fuscus ..."
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doi:10.1242/jeb.044818 Effects of competitive prey capture on flight behavior and sonar beam pattern in paired big brown bats, Eptesicus fuscus
Humpback Whale Song or Humpback Whale Sonar? A Reply to Au et al.
"... Abstract—Au and colleagues ’ arguments against the hypothesis that humpback whale songs function as long-range sonar are based on questionable assumptions rather than on empirical data. Like other echolocating mammals (e.g., bats), singing humpback whales: 1) localize targets in the absence of visua ..."
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Abstract—Au and colleagues ’ arguments against the hypothesis that humpback whale songs function as long-range sonar are based on questionable assumptions rather than on empirical data. Like other echolocating mammals (e.g., bats), singing humpback whales: 1) localize targets in the absence of visual information; 2) possess a highly innervated peripheral auditory system; and 3) modulate the temporal and spectral features of their sounds based on environmental conditions. The sonar equation is inadequate for determining whether humpback whale songs generate detectable echoes from other whales because it does not account for temporal variables that can strongly affect the detectability of echoes. In particular, the sonar equation ignores the fact that much of the noise encountered by singing humpback whales is spectrally and temporally predictable, and that audition in mammals is a dynamic and plastic process. Experiments are needed to test the hypothesis that singing humpback whales listen for and respond to echoes generated by their songs. Index Terms—Baleen whale, cetacean, environmentally-adaptive sonar, low-frequency sonar, mysticete.
unknown title
, 2009
"... Determinants of echolocation call frequency variation in the Formosan lesser horseshoe bat (Rhinolophus monoceros) ..."
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Determinants of echolocation call frequency variation in the Formosan lesser horseshoe bat (Rhinolophus monoceros)
ZOOTAXA
"... Morphological, bioacoustical, and genetic variation in Miniopterus bats from eastern Madagascar, with the description of a new species ..."
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Morphological, bioacoustical, and genetic variation in Miniopterus bats from eastern Madagascar, with the description of a new species
Hearing and Hunting in Red Bats . . .
- J. exp. Biol
, 1997
"... This report describes aspects of hearing in the red bat and relates these to its well-described echolocation and foraging behavior (e.g. Acharya and Fenton, 1992; Balcombe and Fenton, 1988; Dunning et al. 1992; Hickey and Fenton, 1990; Obrist, 1995; Salcedo et al. 1995; Shump and Shump, 1982). Red b ..."
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This report describes aspects of hearing in the red bat and relates these to its well-described echolocation and foraging behavior (e.g. Acharya and Fenton, 1992; Balcombe and Fenton, 1988; Dunning et al. 1992; Hickey and Fenton, 1990; Obrist, 1995; Salcedo et al. 1995; Shump and Shump, 1982). Red bats use sonar signals in the range 30--70 kHz. ABR audiograms demonstrate peak sensitivity in the range 25--30 kHz. Measurements of the sound pressure transformation of the external ear show that the ear creates significant vertical and horizontal localization cues and that these cues are most pronounced at frequencies near 40 kHz. We believe that these properties may reflect adaptations related to the red bat's need to track sonar prey.
