scholarly journals Does Social Complexity Drive Vocal Complexity? Insights from the Two African Elephant Species

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3071
Author(s):  
Daniela Hedwig ◽  
Joyce Poole ◽  
Petter Granli
Keyword(s):  
Communication Systems ◽  
Social Complexity ◽  
Vocal Communication ◽  
Reproductive Rate ◽  
African Elephant ◽  
African Elephants ◽  
Savanna Elephant ◽  
The Social ◽  
Forest Elephant ◽  
Vocal Complexity

The social complexity hypothesis (SCH) for communication states that the range and frequency of social interactions drive the evolution of complex communication systems. Surprisingly, few studies have empirically tested the SHC for vocal communication systems. Filling this gap is important because a co-evolutionary runaway process between social and vocal complexity may have shaped the most intricate communication system, human language. We here propose the African elephant Loxodonta spec. as an excellent study system to investigate the relationships between social and vocal complexity. We review how the distinct differences in social complexity between the two species of African elephants, the forest elephant L. cyclotis and the savanna elephant L. africana, relate to repertoire size and structure, as well as complex communication skills in the two species, such as call combination or intentional formant modulation including the trunk. Our findings suggest that Loxodonta may contradict the SCH, as well as other factors put forth to explain patterns of vocal complexity across species. We propose that life history traits, a factor that has gained little attention as a driver of vocal complexity, and the extensive parental care associated with a uniquely low and slow reproductive rate, may have led to the emergence of pronounced vocal complexity in the forest elephant despite their less complex social system compared to the savanna elephant. Conclusions must be drawn cautiously, however. A better understanding of vocal complexity in the genus Loxodonta will depend on continuing advancements in remote data collection technologies to overcome the challenges of observing forest elephants in their dense rainforest habitat, as well as the availability of directly comparable data and methods, quantifying both structural and contextual variability in the production of rumbles and other vocalizations in both species of African elephants.

scholarly journals Tolerant and intolerant macaques show different levels of structural complexity in their vocal communication

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200439
Author(s):  
Nancy Rebout ◽  
Arianna De Marco ◽  
Jean-Christophe Lone ◽  
Andrea Sanna ◽  
Roberto Cozzolino ◽  
...  
Keyword(s):  
Communication Systems ◽  
Social Complexity ◽  
Vocal Communication ◽  
Rhesus Macaques ◽  
Structural Complexity ◽  
Social Environments ◽  
Social Tolerance ◽  
The Social ◽  
Vocal Signals ◽  
Complexity Hypothesis

We tested the social complexity hypothesis which posits that animals living in complex social environments should use complex communication systems. We focused on two components of vocal complexity: diversity (number of categories of calls) and flexibility (degree of gradation between categories of calls). We compared the acoustic structure of vocal signals in groups of macaques belonging to four species with varying levels of uncertainty (i.e. complexity) in social tolerance (the higher the degree of tolerance, the higher the degree of uncertainty): two intolerant species, Japanese and rhesus macaques, and two tolerant species, Tonkean and crested macaques. We recorded the vocalizations emitted by adult females in affiliative, agonistic and neutral contexts. We analysed several acoustic variables: call duration, entropy, time and frequency energy quantiles. The results showed that tolerant macaques displayed higher levels of vocal diversity and flexibility than intolerant macaques in situations with a greater number of options and consequences, i.e. in agonistic and affiliative contexts. We found no significant differences between tolerant and intolerant macaques in the neutral context where individuals are not directly involved in social interaction. This shows that species experiencing more uncertain social interactions displayed greater vocal diversity and flexibility, which supports the social complexity hypothesis.

scholarly journals Linking social complexity and vocal complexity: a parid perspective

2012 ◽  
Vol 367 (1597) ◽  
pp. 1879-1891 ◽  
Author(s):  
Indrikis Krams ◽  
Tatjana Krama ◽  
Todd M. Freeberg ◽  
Cecilia Kullberg ◽  
Jeffrey R. Lucas
Keyword(s):  
Social Complexity ◽  
Vocal Communication ◽  
Review Literature ◽  
Physiological Factors ◽  
Poecile Carolinensis ◽  
The Social ◽  
Complexity Hypothesis ◽  
The Relationship ◽  
Benefits And Costs ◽  
Vocal Complexity

The Paridae family (chickadees, tits and titmice) is an interesting avian group in that species vary in important aspects of their social structure and many species have large and complex vocal repertoires. For this reason, parids represent an important set of species for testing the social complexity hypothesis for vocal communication—the notion that as groups increase in social complexity, there is a need for increased vocal complexity. Here, we describe the hypothesis and some of the early evidence that supported the hypothesis. Next, we review literature on social complexity and on vocal complexity in parids, and describe some of the studies that have made explicit tests of the social complexity hypothesis in one parid—Carolina chickadees, Poecile carolinensis . We conclude with a discussion, primarily from a parid perspective, of the benefits and costs of grouping and of physiological factors that might mediate the relationship between social complexity and changes in signalling behaviour.

scholarly journals Airborne vocal communication in adult neotropical otters (Lontra longicaudis)

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251974
Author(s):  
Sabrina Bettoni ◽  
Angela Stoeger ◽  
Camilo Rodriguez ◽  
W. Tecumseh Fitch
Keyword(s):  
Communication Systems ◽  
Vocal Communication ◽  
Acoustic Parameters ◽  
Fundamental Frequencies ◽  
Phylogenetic Inertia ◽  
The Social ◽  
Evolution Of Communication ◽  
First Time ◽  
Aquatic Mammals ◽  
Lontra Longicaudis

Most aquatic mammals have complex social and communication systems. Interestingly, little is known about otters’ vocal communication compared to other aquatic mammals. Here, for the first time, we acoustically describe vocalizations of the neotropical otter (Lontra longicaudis), a solitary and endangered New World otter species. We recorded vocalizations and behavioral contexts from six captive neotropical otters at Projeto Lontra, Santa Catarina Island, Brazil. Analysis of acoustic parameters were used to classify the vocalizations according to structure and context. We describe six call types with highly tonal as well as chaotic vocalizations with fundamental frequencies ranging from 90 to 2500 Hz. Additionally, we identified sex differences in the usage of calls. Results suggest that the neotropical river otter has a rich vocal repertoire, similar in complexity to other solitary otter species, but less complex than that of the social giant otter. Despite differences in sociality, phylogeny and ecology, L. longicaudis seems to possess vocalizations homologous to those found in other otters (e.g. hah and chirp), suggesting phylogenetic inertia in otter communicative repertoire. Otters thus offer an interesting but neglected group to explore the evolution of communication systems.

scholarly journals Dwarf mongoose alarm calls: investigating a complex non-human animal call

2020 ◽  
Vol 287 (1935) ◽  
pp. 20192514
Author(s):  
Katie Collier ◽  
Andrew N. Radford ◽  
Sabine Stoll ◽  
Stuart K. Watson ◽  
Marta B. Manser ◽  
...  
Keyword(s):  
Communication Systems ◽  
Vocal Communication ◽  
Vital Role ◽  
Alarm Calls ◽  
Human Communication ◽  
Social Lives ◽  
Novel Approach ◽  
The Social ◽  
Wide Range ◽  
The Individual

Communication plays a vital role in the social lives of many species and varies greatly in complexity. One possible way to increase communicative complexity is by combining signals into longer sequences, which has been proposed as a mechanism allowing species with a limited repertoire to increase their communicative output. In mammals, most studies on combinatoriality have focused on vocal communication in non-human primates. Here, we investigated a potential combination of alarm calls in the dwarf mongoose ( Helogale parvula ), a non-primate mammal. Acoustic analyses and playback experiments with a wild population suggest: (i) that dwarf mongooses produce a complex call type (T 3 ) which, at least at the surface level, seems to comprise units that are not functionally different to two meaningful alarm calls (aerial and terrestrial); and (ii) that this T 3 call functions as a general alarm, produced in response to a wide range of threats. Using a novel approach, we further explored multiple interpretations of the T 3 call based on the information content of the apparent comprising calls and how they are combined. We also considered an alternative, non-combinatorial interpretation that frames T 3 as the origin, rather than the product, of the individual alarm calls. This study complements previous knowledge of vocal combinatoriality in non-primate mammals and introduces an approach that could facilitate comparisons between different animal and human communication systems.

scholarly journals Individual, unit and vocal clan level identity cues in sperm whale codas

2016 ◽  
Vol 3 (1) ◽  
pp. 150372 ◽  
Author(s):  
Shane Gero ◽  
Hal Whitehead ◽  
Luke Rendell
Keyword(s):  
Social Structure ◽  
Communication Systems ◽  
Social Complexity ◽  
Animal Communication ◽  
Sperm Whale ◽  
Ocean Basin ◽  
Photo Identification ◽  
The Social ◽  
Complexity Hypothesis ◽  
Social Units

The ‘social complexity hypothesis’ suggests that complex social structure is a driver of diversity in animal communication systems. Sperm whales have a hierarchically structured society in which the largest affiliative structures, the vocal clans, are marked on ocean-basin scales by culturally transmitted dialects of acoustic signals known as ‘codas’. We examined variation in coda repertoires among both individual whales and social units—the basic element of sperm whale society—using data from nine Caribbean social units across six years. Codas were assigned to individuals using photo-identification and acoustic size measurement, and we calculated similarity between repertoires using both continuous and categorical methods. We identified 21 coda types. Two of those (‘1+1+3’ and ‘5R 1 ’) made up 65% of the codas recorded, were shared across all units and have dominated repertoires in this population for at least 30 years. Individuals appear to differ in the way they produce ‘5R 1 ’ but not ‘1+1+3’ coda. Units use distinct 4-click coda types which contribute to making unit repertoires distinctive. Our results support the social complexity hypothesis in a marine species as different patterns of variation between coda types suggest divergent functions, perhaps representing selection for identity signals at several levels of social structure.

New research frameworks in the study of chimpanzee and gorilla sociality and communication

2019 ◽  
Author(s):  
Sam G. B. Roberts ◽  
Anna Roberts
Keyword(s):  
Social Evolution ◽  
Social Complexity ◽  
Brain Size ◽  
Social Systems ◽  
Strongly Correlated ◽  
The Social ◽  
Human Social Evolution ◽  
Research Frameworks ◽  
New Research ◽  
Large Groups

Group size in primates is strongly correlated with brain size, but exactly what makes larger groups more ‘socially complex’ than smaller groups is still poorly understood. Chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) are among our closest living relatives and are excellent model species to investigate patterns of sociality and social complexity in primates, and to inform models of human social evolution. The aim of this paper is to propose new research frameworks, particularly the use of social network analysis, to examine how social structure differs in small, medium and large groups of chimpanzees and gorillas, to explore what makes larger groups more socially complex than smaller groups. Given a fission-fusion system is likely to have characterised hominins, a comparison of the social complexity involved in fission-fusion and more stable social systems is likely to provide important new insights into human social evolution

scholarly journals Vocal plasticity in a reptile

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170451 ◽  
Author(s):  
Henrik Brumm ◽  
Sue Anne Zollinger
Keyword(s):  
Signal Detection ◽  
Communication Systems ◽  
Vocal Communication ◽  
Animal Communication ◽  
High Amplitude ◽  
Vocal Plasticity ◽  
Lombard Effect ◽  
Gekko Gecko ◽  
High Degree ◽  
Signalling Systems

Sophisticated vocal communication systems of birds and mammals, including human speech, are characterized by a high degree of plasticity in which signals are individually adjusted in response to changes in the environment. Here, we present, to our knowledge, the first evidence for vocal plasticity in a reptile. Like birds and mammals, tokay geckos ( Gekko gecko ) increased the duration of brief call notes in the presence of broadcast noise compared to quiet conditions, a behaviour that facilitates signal detection by receivers. By contrast, they did not adjust the amplitudes of their call syllables in noise (the Lombard effect), which is in line with the hypothesis that the Lombard effect has evolved independently in birds and mammals. However, the geckos used a different strategy to increase signal-to-noise ratios: instead of increasing the amplitude of a given call type when exposed to noise, the subjects produced more high-amplitude syllable types from their repertoire. Our findings demonstrate that reptile vocalizations are much more flexible than previously thought, including elaborate vocal plasticity that is also important for the complex signalling systems of birds and mammals. We suggest that signal detection constraints are one of the major forces driving the evolution of animal communication systems across different taxa.

scholarly journals Discrimination of natural acoustic variation in vocal signals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam R. Fishbein ◽  
Nora H. Prior ◽  
Jane A. Brown ◽  
Gregory F. Ball ◽  
Robert J. Dooling
Keyword(s):  
Zebra Finch ◽  
Acoustic Communication ◽  
Communication Systems ◽  
Vocal Communication ◽  
Relevant Information ◽  
Speech Sounds ◽  
Vocal Signals ◽  
Acoustic Variation ◽  
Zebra Finch Song ◽  
Human Listener

AbstractStudies of acoustic communication often focus on the categories and units of vocalizations, but subtle variation also occurs in how these signals are uttered. In human speech, it is not only phonemes and words that carry information but also the timbre, intonation, and stress of how speech sounds are delivered (often referred to as “paralinguistic content”). In non-human animals, variation across utterances of vocal signals also carries behaviorally relevant information across taxa. However, the discriminability of these cues has been rarely tested in a psychophysical paradigm. Here, we focus on acoustic communication in the zebra finch (Taeniopygia guttata), a songbird species in which the male produces a single stereotyped motif repeatedly in song bouts. These motif renditions, like the song repetitions of many birds, sound very similar to the casual human listener. In this study, we show that zebra finches can easily discriminate between the renditions, even at the level of single song syllables, much as humans can discriminate renditions of speech sounds. These results support the notion that sensitivity to fine acoustic details may be a primary channel of information in zebra finch song, as well as a shared, foundational property of vocal communication systems across species.

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