01884nas a2200169 4500008004100000022001400041245012300055210006900178260001600247300001600263490000800279520131300287100002801600700001901628700001601647856005101663 2018 eng d a0001-496600aAutomatic acoustic estimation of sperm whale size distributions achieved through machine recognition of on-axis clicks0 aAutomatic acoustic estimation of sperm whale size distributions  cJan-12-2018 a3485 - 34950 v1443 a

The waveforms of individual sperm whale clicks often appear as multiple pulses, which are the product of a single pulse reverberating throughout the spermaceti organ. Since there is a relationship between spermaceti organ size and total body size, it is possible to estimate a whale's length by measuring the inter-pulse intervals (IPIs) within its clicks. However, if a click is recorded off-axis, the IPI corresponding to spermaceti organ length is usually obscured. This paper presents an algorithm for automatically estimating the “true” IPIs of sperm whales in a recording by measuring them from on-axis clicks only. The routine works by classifying detected clicks with a support vector machine, assessing the stability of their IPIs, and then clustering the stable IPIs using Gaussian mixture models. Results show that the routine is very accurate in obtaining reliable IPIs, but has a high false negative rate. Nonetheless, since sperm whales click very frequently, it is possible to obtain useful IPI distributions with only a few minutes of recording. This algorithm makes it possible to estimate the body lengths of multiple sperm whales automatically with only one hydrophone. An implementation is available for download at http://whitelab.biology.dal.ca/CABLE/cable.htm.

1 aBeslin, Wilfried, A. M.1 aWhitehead, Hal1 aGero, Shane uhttp://asa.scitation.org/doi/10.1121/1.508229102438nas a2200277 4500008004100000022001300041245011600054210006900170260001600239300001400255490000800269520143800277653001201715653001201727653001601739653001601755653001601771653001901787653001701806100002601823700002501849700001801874700001901892700001601911856023301927 2018 eng d a0003347200aKinship and association do not explain vocal repertoire variation among individual sperm whales or social units0 aKinship and association do not explain vocal repertoire variatio cJan-11-2018 a131 - 1400 v1453 a

Vocal learning often results in distinct dialects among individuals or groups, but the forces selecting for these phenomena remain unclear. Female sperm whales, Physeter macrocephalus, and their dependent offspring live in matrilineally based social units, and the units associate within sympatric clans. The clans have distinctive dialects of codas (patterns of clicks), as do, to a lesser extent, the units within clans. We examined the similarity of coda repertoires of individuals and units from the eastern Caribbean and related these to patterns of kinship and social association. Similarity in coda repertoires was not discernibly correlated with close kinship or association rates for either individuals or units (matrix correlation coefficients <0.12 for all tests using whole repertoires and data from all units). This supports the prevailing hypothesis that these vocalizations are culturally transmitted. The lack of correlation also indicates that vocal learning may occur broadly within clans, rather than preferentially from close kin or close social associates within social units, or that biases in vocal learning at lower levels of social structure are diffused by clan-level processes, such as conformity. Finally, an absence of signals of kinship in vocalization patterns suggests that a different mechanism, perhaps familiarity through repeated association, mediates kin selection among sperm whales.

10adialect10akinship10amatrilineal10asocial unit10asperm whale10avocal learning10avocalization1 aKonrad, Christine, M.1 aFrasier, Timothy, R.1 aRendell, Luke1 aWhitehead, Hal1 aGero, Shane uhttps://linkinghub.elsevier.com/retrieve/pii/S0003347218302811https://api.elsevier.com/content/article/PII:S0003347218302811?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302811?httpAccept=text/plain02009nas a2200181 4500008004100000022001400041245013400055210006900189260001600258300001400274490000800288520140200296100002001698700001601718700002301734700001901757856005101776 2018 eng d a0001-496600aVariability of the inter-pulse interval in sperm whale clicks with implications for size estimation and individual identification0 aVariability of the interpulse interval in sperm whale clicks wit cJan-07-2018 a365 - 3740 v1443 a

Sperm whales generate multi-pulsed clicks for echolocation and communication with an inter-pulse interval (IPI) determined by the size of their hypertrophied sound producing nose. The IPI has therefore been used to estimate body size and distinguish between individuals, and it has been hypothesized that conspecifics may use IPIs to recognize each other. However, the degree to which IPIs vary within individuals has not explicitly been tested, and therefore the inherent precision of this measure and its applicability for size estimation for researchers and sperm whales alike remain unknown. Here, the variability in IPI from both animal-borne Dtags and far-field recordings from echolocating and communicating sperm whales is quantified. Three different automatic methods (envelope, cepstrum, and cross-correlation) are tested and it is found that the envelope approach results in the least dispersion. Furthermore, it is shown that neither growth, depth, nor recording aspect fully explains the observed variability among clicks recorded from the same individual. It is proposed that dynamics in the soft structures of the nose are affecting IPIs, resulting in a variation of approximately 0.2 ms. Therefore, it is recommended that this variation be considered in IPI studies and that IPIs may have limited functionality as an identity cue among large groups of conspecifics.

1 aBøttcher, Anne1 aGero, Shane1 aBeedholm, Kristian1 aWhitehead, Hal uhttp://asa.scitation.org/doi/10.1121/1.5047657