Communication / Vocal / Hearing
Clemins, P.J., M.T. Johnson, K.M. Leong, and A. Savage (2005). Automatic classification and speaker identification of African elephant (Loxodonta africana) vocalizations. Journal of the Acoustical Society of America 117(2): 956-63.
NAL Call Number: QC221.A27
Abstract: A hidden Markov model (HMM) system is presented for automatically classifying African elephant vocalizations. The development of the system is motivated by successful models from human speech analysis and recognition. Classification features include frequency-shifted Mel-frequency cepstral coefficients (MFCCs) and log energy, spectrally motivated features which are commonly used in human speech processing. Experiments, including vocalization type classification and speaker identification, are performed on vocalizations collected from captive elephants in a naturalistic environment. The system classified vocalizations with accuracies of 94.3% and 82.5% for type classification and speaker identification classification experiments, respectively. Classification accuracy, statistical significance tests on the model parameters, and qualitative analysis support the effectiveness and robustness of this approach for vocalization analysis in nonhuman species.
Descriptors: phonetics, signal processing, computer assisted, sound spectrography classification, speech acoustics, vocalization, animal classification, acoustics, animal identification systems classification, fourier analysis, Markov chains, reproducibility of results, sound spectrography statistics and numerical data.
Garstang, M. (2004). Long-distance, low-frequency elephant communication. Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology 190(10): 791-805.
NAL Call Number: QP33.68
Descriptors: communication, physiology, auditory threshold, hearing physiology, sex behavior, social behavior, sound, sound localization, vocalization, weather.
Garstang, M. (2005). Long-distance, low-frequency elephant communication (vol 190, pg 791, 2004). Journal of Comparative Physiology A Neuroethology Sensory Neural and Behavioral Physiology 191(3): 299. ISSN: 0340-7594.
NAL Call Number: QP33.68
Descriptors: long distance communication, low frequency communication.
Leighty, K.A., J. Soltis, K. Leong, and A. Savage (2008). Antiphonal exchanges in African elephants (Loxodonta africana): collective response to a shared stimulus, social facilitation, or true communicative event? Behaviour 145(Part 3): 297-312. ISSN: 0005-7959; Online: 1568-539X.
Descriptors: African elephant, Loxodonta africana, communication, social relationship, vocal response, rumble vocalization, shared stimulus, antiphonal exchange, true communicative event.
Leighty, K.A., J. Soltis, C.M. Wesolek, and A. Savage (2008). Rumble vocalizations mediate interpartner distance in African elephants, Loxodonta africana. Animal Behaviour 76(Part 5): 1601-1608. ISSN: 0003-3472; Online: 1095-8282.
Descriptors: African elephant, Loxodonta africana, communication, social organization, rumble vocalization, antiphonal exchange, spatial cohesion, interpartner distance, close distance social interaction.
Leong, K.M., K. Burks, C.E. Rizkalla, and A. Savage (2005). Effects of reproductive and social context on vocal communication in captive female African elephants (Loxodonta africana). Zoo Biology 24(4): 331-347. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: zoo animals, vocalization, social dominance, estrous cycle, hormone secretion, females, males, social behavior.
Leong, K.M., A. Ortolani, L.H. Graham, and A. Savage (2003). The use of low-frequency vocalizations in African elephant (Loxodonta africana) reproductive strategies. Hormones and Behavior 43(4): 433-43.
NAL Call Number: QP801.H7H64
Abstract: Fertility-advertisement calls in females are predicted to occur in nonmonogamous species where males and females are widely separated in space. In African elephants, low-frequency vocalizations have thus been suggested as a reproductive strategy used by fertile females to attract mates. This study examined the use of low-frequency vocalizations with respect to different phases of the estrous cycle in African elephants by simultaneously monitoring vocalizations, behavior, and hormonal profiles. Subjects were one male and six female African elephants housed at Disney's Animal Kingdom. No acoustically distinct vocalizations were restricted to the ovulatory follicular phase. However, overall rate of low-frequency vocalization as well as the rate of one acoustically distinct vocalization changed over the estrous cycle, with highest rates of calling related to the first period of follicular growth, or anovulatory follicular phase. Elevated rates of vocalization thus were not restricted to behavioral estrus and occurred much earlier in the estrous cycle than in most species that produce fertility-advertisement calls. Both herd composition and elephant identity also affected rates of vocalization. Vocalizations therefore may not be reliable signals of actual fertility. However, the increase in vocalizations in advance of estrus may attract males to the herd prior to ovulation, facilitating both male-male competition and female choice. Once present in the herd, males may then switch strategies to use more reliable chemical and visual cues to detect ovulating females.
Descriptors: physiology, sex behavior, animal physiology, vocalization, estrous cycle physiology, luteinizing hormone blood, ovulation physiology, reproduction physiology, social behavior.
Leong, K., A. Ortolani, K. Burks, J. Mellen, and A. Savage (2003). Quantifying acoustic and temporal characteristics of vocalizations for a group of captive African elephants Loxodonta africana. Bioacoustics 13(3): 213-231. ISSN: 0952-4622.
Descriptors: African elephant, Loxodonta africana, coumminication, acoustic signals, vocalizations, acoustic and temporal characteristics, low frequency, rumbles, complex repertoire.
McComb, K., D. Reby, and L. Baker (2003). Long-distance communication of acoustic cues to social identity in African elephants. Animal Behaviour 65: 317-29.
NAL Call Number: Film S-1802
Descriptors: communication, acoustic cues, long distance, social identity, infrasonic calls, low frequencies.
Meyer, J.M., T.E. Goodwin, and B.A. Schulte (2008). Intrasexual chemical communication and social responses of captive female African elephants, Loxodonta africana. Animal Behaviour 76(1): 163-174. ISSN: 0003-3472.
Descriptors: African elephant, Loxodonta africana, social behavior, communication, ovulation, zoo animals.
O' Connell Rodwell, C.E., J.D. Wood, T.C. Rodwell, S. Puria, S.R. Partan, R. Keefe, D. Shriver, B.T. Arnason, and L.A. Hart (2006). Wild elephant (Loxodonta africana) breeding herds respond to artificially transmitted seismic stimuli. Behavioral Ecology and Sciobiology 59(6): 842-850. ISSN: 0340-5443.
NAL Call Number: QL751.B4
Abstract: Seismic communication is known to be utilized in insects, amphibians, reptiles, and small mammals, but its use has not yet been documented in large mammals. Elephants produce low-frequency vocalizations, and these vocalizations have seismic components that propagate in the ground, but it has not yet been demonstrated that elephants can detect or interpret these seismic signals. In this study, we played back seismic replicates of elephant alarm vocalizations to herds of wild African elephants in their natural environment and observed significant behavioral changes indicating that they had detected these signals. Seismic communication may provide an important complement to existing communication modes used by elephants. Seismic sensitivity may also provide elephants with an additional modality for sensing important environmental cues such as changes in weather patterns or seismic disturbances.
Descriptors: African elephant, Loxodonta africana, Elephant seismic communication, seismic stimuli, replicas, elephant alarm vocalizations.
O'connell Rodwell, C.E., J.D. Wood, C. Kinzley, T.C. Rodwell, J.H. Poole, and S. Puria (2007). Wild african elephants (Loxodonta africana) discriminate between familiar and unfamiliar conspecific seismic alarm calls. Journal of the Acoustical Society of America 122(2): 823-830. ISSN: 0001-4966.
Descriptors: African elephant, Loxodonta africana, communication, call discrimination, vibration communication, conspecific seismic alarm call.
Payne, K.B., M. Thompson, and L. Kramer (2003). Elephant calling patterns as indicators of group size and composition: The basis for an acoustic monitoring system. African Journal of Ecology 41(1): 99-107. ISSN: 0141-6707.
NAL Call Number: 409.6 EA7
Descriptors: African elephants, Loxodonta africana, behavior, acoustic activity analysis, acoustic monitoring, acoustic signals, calling patterns, variation, group size, composition, Namibia, vocal activity, remote monitoring, calls, low frequency, high frequency.
Language of Text: English, with English and French summaries.
Soltis, J., K.A. Leighty, C.M. Wesolek, and A. Savage (2009). The expression of affect in African elephant (Loxodonta africana) rumble vocalizations. Journal of Comparative Psychology 123(2): 222-225. ISSN: 0735-7036.
Descriptors: African elephant, Loxodonta africana, communication, social interaction, dominance interaction, rumble vocalization.
Soltis, J., K. Leong, and A. Savage (2005). African elephant vocal communication. I. antiphonal calling behaviour among affiliated females. Animal Behaviour 70(3): 579-87.
NAL Call Number: Film S-1802
Descriptors: vocal communication, calling behavior, females, antiphonal.
Soltis, J., K. Leong, and A. Savage (2005). African elephant vocal communication. II. rumble variation reflects the individual identity and emotional state of callers. Animal Behaviour 70(3): 589-99.
NAL Call Number: Film S-1802
Descriptors: vocal communication, rumble variation, individual identity.
Wesolek, C.M., J. Soltis, K.A. Leighty, and A. Savage (2009). Infant african elephant rumble vocalizations vary according to social interactions with adult females. Bioacoustics 18(3): 227-239. ISSN: 0952-4622.
Descriptors: African elephant, Loxodonta africana, communication, custom designed audio recording collar, maternal responsiveness, rumble vocalization, affiliative social interaction.
Wood, J.D., B. Mccowan, W.R. Langbauer Jr., J.J. Viljoen, and L. Hart (2005). Classification of African elephant, Loxodonta africana, rumbles using acoustic parameters and cluster analysis. Bioacoustics 15(2): 143-161. ISSN: 0952-4622.
Descriptors: African elephant, rumbles, acoustic parameters, cluster analysis, calls, types, vocalizations, feeding, resting, categorized.