Sperm whale social units: variation and change

Christal, Jenny; Whitehead, Hal; Lettevall, Erland

doi:10.1139/cjz-76-8-1431

Cited by 60 publications

(108 citation statements)

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“…We wanted to know whether genetic variation could account for behavioural variation between clans. Referring to the expectations we laid out in the introduction, we have shown that mtDNA haplotypes are shared extensively among clans, which is inconsistent with a largely genetic casual basis for vocal variation, but is consistent with photo-identification studies showing females occasionally n #a #b #c #e #g #i #j #d #o #n #f #m #h switching social units and more rarely, clans (Christal et al 1998;Rendell and Whitehead 2003a). We did find a correlation between vocal and genetic similarities between groups, but the variance component associated with vocal clan membership was swamped by the components attributed to variation between and within groups-depending on the analysis, between 92 and 98% of the genetic variation we observed occurred within clans-and the statistical Table 2 Segregating sites in the 399 bp 5 0 mtDNA control region sequence.…”

Section: Discussionsupporting

confidence: 79%

“…Female and immature sperm whales live in long-term bond groups called social units, which are partially matrilineal but may contain two or more unrelated matrilines (Christal et al 1998;Lyrholm and Gyllensten 1998;Mesnick 2001). At sea, these units are usually encountered in temporary association with other units, forming what have been termed social groups (Christal et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus?

et al. 2011

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Sperm whale social groups can be assigned to vocal clans based on their production of codas, short stereotyped patterns of clicks. It is currently unclear whether genetic variation could account for these behavioural differences. We studied mitochondrial DNA (mtDNA) variation among sympatric vocal clans in the Pacific Ocean, using sequences extracted from sloughed skin samples. We sampled 194 individuals from 30 social groups belonging to one of three vocal clans. As in previous studies of sperm whales, mtDNA control region diversity was low (π = 0.003), with just 14 haplotypes present in our sample. Both hierarchical AMOVAs and partial Mantel tests showed that vocal clan was a more important factor in matrilineal population genetic structure than geography, even though our sampling spanned thousands of kilometres. The variance component attributed to vocal dialects (7.7%) was an order of magnitude higher than those previously reported in birds, while the variance component attributed to geographic area was negligible. Despite this, the two most common haplotypes were present in significant quantities in each clan, meaning that variation in the control region cannot account for behavioural variation between clans, and instead parallels the situation in humans where parent-offspring transmission of language variation has resulted in correlations with neutral genes. Our results also raise questions for the management of sperm whale populations, which has traditionally been based on dividing populations into geographic 'stocks', suggesting that culturally-defined vocal clans may be more appropriate management units.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus?

et al. 2011

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“…The use of a daily sampling interval removes demographic effects (Whitehead & Dufault, 1999); and (3) '2 h', the approximate duration of two dive cycles in this species, which provides more samples while maintaining independence, and has proven useful in previous work on this species (Christal & Whitehead, 2001;Christal et al, 1998). Three combinations of sampling period and association measure are uninformative: 'dateedate' and '2 he2 h', in which the sampling period is equal to the measure of association, and '2 hedate', in which the measure of association is longer than the sampling period.…”

Section: Defining Associations Between Unitsmentioning

confidence: 98%

“…In general, clusters were small (mean ± SD ¼ 1.75 ± 1.24 individuals) and were visually distinct at sea being separated by hundreds to thousands of metres based on GPS locations of identification photographs (Gero et al, 2014). Social differentiation within units was estimated, using a half-weight index (HWI) of association (Cairns & Schwager, 1987), defining association as being sighted in the same cluster, and using 2 h sampling periods as in previous work in this species (Christal, Whitehead, & Lettevall, 1998;Christal & Whitehead, 2001;Gero et al, 2009Gero et al, , 2008Gero et al, , 2013. The likelihood method described by Whitehead (2008a) was used to calculate values of social differentiation and its standard error (SE) was estimated using the nonparametric bootstrap with sampling periods chosen randomly with replacement for each of 1000 bootstrap samples.…”

Section: Social Differentiation Within Unitsmentioning

confidence: 99%

Individualized social preferences and long-term social fidelity between social units of sperm whales

2015

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“…To investigate the stability of groups over time, we defined the term "unit" following the procedure proposed by Christal et al (1998) in sperm whales and Ottensmeyer and Whitehead (2003) for long-finned pilot whales. Individuals sighted in at least five different years, each observation of the individual in a group separated from the preceding one by a gap of at least 180 days, were identified as "key individuals".…”

Section: Unit Membershipmentioning

confidence: 99%

Long-term social structure of long-finned pilot whales (Globicephala melas) in the Strait of Gibraltar

et al. 2008

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The Strait of Gibraltar is inhabited by around 216 pilot whales, which are present all year round, and nothing is known about their social structure. The aim of this study is to analyse the inter-individual association patterns within this pilot whales community to (1) provide an insight on their long-term social system and (2) to assess the relationship between sexes within this social system. Between 1999 and 2006, 23,004 km was sampled in the Strait of Gibraltar, and 4,887 images of dorsal fins of pilot whales were taken from 226 groups. The sex of 56 of the individuals could be determined genetically. The strength of the behavioural relationships between dyads of individuals was calculated, and the temporal aspects of the social structure were evaluated, showing in a non-random social structure made by constant companions. The preferred associations between individuals consisted in associations of males-females. Eight long-term units could be found with different degrees of association rates. Consequently, we propose that, in the Strait, the pilot whales exhibit a hierarchical social system composed of a population encompassing several clans of pilot whales each containing several pods. Pods will then be formed by several line units, similar to killer whale matrilineal units.

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Sperm whale social units: variation and change

Cited by 60 publications

References 0 publications

Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus?

Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus?

Individualized social preferences and long-term social fidelity between social units of sperm whales

Long-term social structure of long-finned pilot whales (Globicephala melas) in the Strait of Gibraltar

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