[MARMAM] Kinship in sperm whales

Hal Whitehead Hal.Whitehead at Dal.Ca
Sat Nov 10 09:13:58 PST 2018


We are pleased to announce the publication of two papers on how kinship relates to alloparental care and vocal repertoire in sperm whales, respectively:

Konrad, C.M., T. Frasier, H. Whitehead and S. Gero. 2018. Kin selection and allocare in sperm whales. Behavioral Ecology

Konrad, C.M., T. Frasier, L. Rendell, H. Whitehead and S. Gero. 2018. Kinship and association do not explain vocal repertoire variation among individual sperm whales or social units. Animal Behaviour 145: 131-140.

PDF's of both papers are available at our lab. website: http://whitelab.biology.dal.ca/labpub.htm

Hal Whitehead, Dalhousie University

Abstracts:
Konrad, C.M., T. Frasier, H. Whitehead and S. Gero. 2018. Kin selection and allocare in sperm whales. Behavioral Ecology
Cooperative care and defense of young are hypothesized to be foundational to the societies of several species, including the sperm whale (Physeter macrocephalus). However, the extent of allocare among sperm whales and the mechanisms driving it have not been well-characterized. Sperm whale social units are matrilineally based, making kin selection a likely key driver of allocare, but the relationship between kinship and calf care is essentially unknown. We investigate calf care in the context of kinship, by combining association and interaction data with genetic profiles for 16 calves from 7 eastern Caribbean social units. Mothers were the primary associate for 62.5% of calves, and the primary nurse for 87.5%, so behavioral observations are not always sufficient for assigning maternity. Babysitting and allonursing were frequent in some cases, particularly for calves less than a year old. Within social units, babysitting rates were correlated with relatedness (rs = 0.4, P < 0.05), and allonurses were, on average, closer maternal relatives of the calves they nursed than were available females who were not allonurses (Δr = 0.14, P = 0.054). Exceptions to the overall positive relationship between allocare and kinship suggest that additional factors influencing allocare among sperm whales may include reciprocity, group augmentation and gaining maternal experience.

Konrad, C.M., T. Frasier, L. Rendell, H. Whitehead and S. Gero. 2018. Kinship and association do not explain vocal repertoire variation among individual sperm whales or social units. Animal Behaviour 145: 131-140.
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.



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