@article {53227,
	title = {Wolf howls encode both sender- and context-specific information},
	journal = {Animal Behaviour},
	volume = {145},
	year = {2018},
	month = {Jan-11-2018},
	pages = {59 - 66},
	abstract = {<p>Loud, long-distance calls serve varied functions across animal species including marking territory, attracting mates and signalling one\&$\#$39;s identity. Here, we examined the types of sender- and context-specific information encoded in the howls of captive timber wolves, Canis lupus. We analysed 913 howls from nine individuals across three packs and investigated whether howl structure varied consistently as a function of phenotypic factors (age class, sex, pack and identity of the caller) in addition to the context in which the call was produced: specifically, whether the call was produced in a \&lsquo;spontaneous\&rsquo; context just after sunrise or was \&lsquo;elicited\&rsquo; by the absence of a group member. Calls were correctly classified by individual identity and production context, but not by any other factors. Principal components analyses indicated that individual differences were primarily associated with frequency-based measures, whereas acoustic variation between production contexts was associated with a variety of frequency-, intensity- and energy-based measures. Recognition of individual differences in vocalizations is likely to be important for navigating social relationships in wolves and further work is required to determine which life history factors may shape these individual differences. Differences resulting from production context are suggestive that these howl variants may serve different functions. The extent to which these individual and contextual differences are understood by receivers remains an open question.</p>
},
	issn = {00033472},
	doi = {10.1016/j.anbehav.2018.09.005},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0003347218302756https://api.elsevier.com/content/article/PII:S0003347218302756?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302756?httpAccept=text/plain},
	author = {Watson, Stuart K. and Townsend, Simon W. and Range, Friederike}
}
@article {52573,
	title = {Call concatenation in wild meerkats},
	journal = {Animal Behaviour},
	volume = {134},
	year = {2017},
	month = {Jan-12-2017},
	pages = {257 - 269},
	abstract = {<p>Repertoire size, frequently determined by the number of discrete call types, has been used to assess vocal complexity in animals. However, species can also increase their communicative complexity by using graded signals or by combining individual calls. Animal call sequences can be divided into two main categories, each subdivided into two classes: repetitions, with either an unlimited or finite number of iterations of the same call type, and mixed call combinations, composed of two or more graded or discrete call types. Social contexts involve a wide range of behaviours and, unlike predation contexts, can be associated with both positive and negative emotions. Therefore, interactions linked to social contexts may place additional demands on an animal\&$\#$39;s communicative system and lead to the use of call com- binations. We systematically documented call combinations produced by wild meerkats, Suricata sur- icatta, a highly social carnivore, in social contexts in their natural habitat. We observed 12 distinct call combinations belonging to all four classes of combination, produced in all the observed behavioural contexts. Four combinations were each produced in a specific context whereas the remaining eight were produced in several contexts, albeit in different proportions. The broad use of combinations suggests that they represent a non-negligible part of meerkat social communication and that they can be used in flexible ways across various behavioural contexts. Comparison with combinations produced in predation contexts indicated that social call combinations are more varied in number of classes and structural complexity than the former, perhaps due to the greater variety of social contexts. However, in meerkats, combinations of functionally referential calls have been documented in predation but not social contexts, suggesting that both social and predation pressures may play a role in the evolution of combinatoriality in animal communication.</p>
},
	keywords = {call combination, meerkat, natural observations, social context, vocal communication},
	issn = {00033472},
	doi = {10.1016/j.anbehav.2016.12.014},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347216303463},
	author = {Collier, Katie and Townsend, Simon W.}
}
