Alliance-specific habitat selection by male Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia

O’Brien, Orfhlaith; Allen, S. J.; Krützen, Michael; Connor, Richard C.

doi:10.1016/j.anbehav.2020.03.014

Cited by 12 publications

(5 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We did not include male age in our analyses because age is a significant predictor of alliance formation, i.e., second-order allies tend to be of a similar age ( 27 ), age does not influence a male’s number of paternities ( 25 ), and mature males of all ages participate in third-order alliances ( 24 , 29 ). We have suggested that alliance partners are selected strategically based on social and ecological homophily, because alliances with broadly overlapping ranges differ in preferred foraging habitat and behavior (( 37 , 38 ), see SI Appendix ). Our finding that second-order alliance size is unrelated to consortship rate and duration is unsurprising if second-order alliance size is related to alliance variation in foraging behavior ( 38 ) and perhaps demographic variation in the availability of potential partners.…”

Section: Discussionmentioning

confidence: 99%

“…We have suggested that alliance partners are selected strategically based on social and ecological homophily, because alliances with broadly overlapping ranges differ in preferred foraging habitat and behavior (( 37 , 38 ), see SI Appendix ). Our finding that second-order alliance size is unrelated to consortship rate and duration is unsurprising if second-order alliance size is related to alliance variation in foraging behavior ( 38 ) and perhaps demographic variation in the availability of potential partners. However, we have shown that the strategic investment in third-order alliance relationships does increase access to a contested resource, through an increase in the duration of consortships.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Strategic intergroup alliances increase access to a contested resource in male bottlenose dolphins

Connor

Krützen

Allen

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Efforts to understand human social evolution rely largely on comparisons with nonhuman primates. However, a population of bottlenose dolphins in Shark Bay, Western Australia, combines a chimpanzee-like fission-fusion grouping pattern, mating system, and life history with the only nonhuman example of strategic multilevel male alliances. Unrelated male dolphins form three alliance levels, or “orders”, in competition over females: both within-group alliances (i.e., first- and second-order) and between-group alliances (third-order), based on cooperation between two or more second-order alliances against other groups. Both sexes navigate an open society with a continuous mosaic of overlapping home ranges. Here, we use comprehensive association and consortship data to examine fine-scale alliance relationships among 121 adult males. This analysis reveals the largest nonhuman alliance network known, with highly differentiated relationships among individuals. Each male is connected, directly or indirectly, to every other male, including direct connections with adult males outside of their three-level alliance network. We further show that the duration with which males consort females is dependent upon being well connected with third-order allies, independently of the effect of their second-order alliance connections, i.e., alliances between groups increase access to a contested resource, thereby increasing reproductive success. Models of human social evolution traditionally link intergroup alliances to other divergent human traits, such as pair bonds, but our study reveals that intergroup male alliances can arise directly from a chimpanzee-like, promiscuous mating system without one-male units, pair bonds, or male parental care.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Strategic intergroup alliances increase access to a contested resource in male bottlenose dolphins

Connor

Krützen

Allen

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The shallow and protected estuary habitat provides resources that allow dolphins to reside year-round, with prey availability being continuous and more dependable than that in coastal habitats (McCluskey et al 2016). Habitat and prey selection is therefore likely to influence how dolphins associate (Holyoake et al 2010;O'Brien et al 2020;McCluskey et al 2021;Nicholson et al 2021).…”

Section: Discussionmentioning

confidence: 99%

Evidence of male alliance formation in a small dolphin community

et al. 2022

View full text Add to dashboard Cite

The photo-identification of uniquely marked individuals has revealed much about mammalian behaviour and social structure in recent decades. In bottlenose dolphins (Tursiops spp.), for example, the long-term tracking of individuals has unveiled considerable variation in social structure among populations and various spatio-temporal aspects of group formation. In this study, we investigated associations among individual males in a small community of Indo-Pacific bottlenose dolphins (T. aduncus) residing in an urbanized estuary in southwestern Australia. Given the relative proximity of our study area to other populations in which complex male alliances form for the purpose of mate acquisition, we used long-term photo-identification records and social analyses to assess whether such alliances also occur in smaller and more isolated settings. Our work revealed strong social bonds and long-term, non-random associations among individual males, suggesting the occurrence of male alliances. Behavioural observations of alliances interacting with potentially receptive adult females from the estuary community and from adjacent communities, and exhibiting sexual display behaviours near females, suggest that these alliances occur in a reproductive context. As the first formal analysis indicating the occurrence of male alliances outside Shark Bay along the vast western coastline of Australia, this study complements previous research and extends our understanding of the evolutionary and ecological processes that drive alliance formation.

show abstract

“…The male bottlenose dolphins in Shark Bay participate in up to three levels or orders of alliances in a large, open society of resident dolphins with a dynamic fission–fusion grouping pattern (Connor and Krützen 2015 ; Gerber et al 2020 , 2021 ; King et al 2021 ). Males have larger ranges than females but retain their natal range in their adult home range (Connor et al 2000 ; Krützen et al 2004 ; Tsai and Mann 2013 ) and both sexes exhibit a continuous mosaic of overlapping home ranges (Watson-Capps 2005 ; Randić et al 2012 ; O’Brien et al 2020 ). Second-order alliances contain 4–14 males, may endure for decades, and are considered the core unit of male social organization in Shark Bay.…”

Section: Introductionmentioning

confidence: 99%

Inter-group alliance dynamics in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

et al. 2023

View full text Add to dashboard Cite

The social intelligence hypothesis holds that complex social relationships are the major selective force underlying the evolution of large brain size and intelligence. Complex social relationships are exemplified by coalitions and alliances that are mediated by affiliative behavior, resulting in differentiated but shifting relationships. Male Indo-Pacific bottlenose dolphins in Shark Bay, Australia, form three alliance levels or ‘orders’, primarily among non-relatives. Strategic alliance formation has been documented within both first- and second-order alliances and between second-order alliances (‘third-order alliances’), revealing that the formation of strategic inter-group alliances is not limited to humans. Here we conducted a fine-scale study on 22 adult males over a 6-year period to determine if third-order alliance relationships are differentiated, and mediated by affiliative interactions. We found third-order alliance relationships were strongly differentiated, with key individuals playing a disproportionate role in maintaining alliances. Nonetheless, affiliative interactions occurred broadly between third-order allies, indicating males maintain bonds with third-order allies of varying strength. We also documented a shift in relationships and formation of a new third-order alliance. These findings further our understanding of dolphin alliance dynamics and provide evidence that strategic alliance formation is found in all three alliance levels, a phenomenon with no peer among non-human animals.

show abstract

Alliance-specific habitat selection by male Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia

Cited by 12 publications

References 69 publications

Strategic intergroup alliances increase access to a contested resource in male bottlenose dolphins

Strategic intergroup alliances increase access to a contested resource in male bottlenose dolphins

Evidence of male alliance formation in a small dolphin community

Inter-group alliance dynamics in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

Contact Info

Product

Resources

About