We are pleased to share our new publication in Royal Society Open Science titled Evidence that bottlenose dolphins can communicate with vocal signals to solve a cooperative task by StephanieL. King, Emily Guarino, Katy Donegan, Christina McMullen and Kelly Jaakkola.
Abstract: Cooperation experiments have long been used to explore the cognition underlying animals' coordination towards a shared goal. While the ability to understand the need for a partner in a cooperative task has been demonstrated in a number of species, there has been far less focus on cooperation experiments that address the role of communication. In humans, cooperative efforts can be enhanced by physical synchrony, and coordination problems can be solved using spoken language. Indeed, human children adapt to complex coordination problems by communicating with vocal signals. Here, we investigate whether bottlenose dolphins can use vocal signals to coordinate their behaviour in a cooperative button-pressing task. The two dolphin dyads used in this study were significantly more likely to cooperate successfully when they used whistles prior to pressing their buttons, with whistling leading to shorter button press intervals and more successful trials. Whistle timing was important as the dolphins were significantly more likely to succeed if they pushed their buttons together after the last whistle, rather than pushing independently of whistle production. Bottlenose dolphins are well known for cooperating extensively in the wild, and while it remains to be seen how wild dolphins use communication to coordinate cooperation, our results reveal that at least some dolphins are capable of using vocal signals to facilitate the successful execution of coordinated, cooperative actions.
The paper is OA and can be found here: https://royalsocietypublishing.org/doi/10.1098/rsos.202073
Over six episodes, Chris Packham’s Animal Einsteins looks at how Earth’s savviest species have sharpened their skills to thrive in the animal kingdom. Their cunning tricks and unique techniques are being brought to BBC Two by the BBC Studios Natural History Unit, based in Bristol.
In episode 2, Stephanie discussed how dolphins synchronise their calls with the calls of their peers to increase feelings of team bonding – a type of shared experience we used to think was unique to humans. Bottlenose dolphins can form alliances that last decades and they advertise these relationships with synchronised body movements, our research has shown that synchronised calls also play a vital role.
You can catch up with the episode here: https://www.bbc.co.uk/programmes/m000stfb
Pernille and Stephanie are working with the team at the Dolphin Research Center on an exciting new project investigating how anthropogenic noise affects cooperation in dolphins using acoustic and movement recording, non-invasive tags! This will be one of many exciting pieces of work from Pernille's PhD research.
Follow Pernille on twitter (@PernilleMS) for project updates.
Early April sees another paper out of our long-term dolphin research off Monkey Mia in the eastern gulf of Shark Bay. This research represents the fruition of an excellent Masters thesis by Bronte Moore.
Why is this interesting?
Allied male dolphins in Shark Bay use coercive vocalisations called “pops” to herd females. Pops are usually produced in trains by one male, but recent observations suggested multiple males might coordinate pop production...
Using acoustic localisation, we confirmed pops came from different bearings and that it was indeed two animals coordinating their pop trains (male A and male B). Further, males would match each other’s pop tempo and produce their pop trains in unison...
n humans, synchronised actions lead to increased feelings of bonding, foster cooperation and diminish the perceived threat of rivals. Male dolphins are also known for their remarkable motor synchrony...
Our study shows that acoustic coordination and synchrony is also important for allied male dolphins. We suggest that, like in humans, physical AND vocal coordination in dolphins promote cooperation and social bonding.
Full citation: Moore BL, Connor RC, Allen SJ, Krützen M, King SL. 2020 Acoustic coordination by allied male dolphins in a cooperative context. Proc. R. Soc. B 287: 20192944. http://dx.doi.org/10.1098/rspb.2019.2944
Watch this space for forthcoming updates on this remarkable dolphin population…
Congratulations to PhD candidate Pernille Meyer Sørensen for being awarded a Nat Geo Early Career Grant for her PhD research!
Big thanks to National Geographic for our new grant awarded to Pernille for her PhD research investigating how acoustic detection range changes as a function of habitat configuration, and how this may shape sociality and cooperative strategies within a single population of wild animals. #sharkbay
Follow @PernilleMS on Twitter for project updates
Title: Vocal behaviour of allied male dolphins during cooperative mate guarding.
Authors: King SL, Allen SJ, Krützen M, Connor RC.
Abstract: Coercive mate guarding, where males use aggression to control female movements, is a form of sexual coercion which functions to constrain female mate choice. Non-human primates, for example, herd females to keep them away from competing males, but male bottlenose dolphins (Tursiops aduncus) also herd females to keep them close to their alliance partners. Indeed, pairs and trios of male dolphins work together to sequester single estrus females and defend them from competing alliances. Yet how males facilitate such coordination remains unknown. Here, we investigate the vocal behaviour of allied male bottlenose dolphins during the herding of individual females, examining how the production of whistles and ‘pops’ (a threat vocalisation) varied with behavioural state and inter-animal distances. Allied males produced both whistles and pops significantly more often and at higher rates during social interactions, though they differed in function. Whistle rates increased significantly when new individuals joined the consorting group, consistent with previous work showing that whistles are part of a greeting sequence for this species. Whistle matching also appeared to play a role in within-alliance coordination. Pop vocalisations increased significantly when the nearest male to the female changed, likely inducing the female to remain close as the males coordinate a guard switch. Building upon prior research examining female movements in response to pops, we show that males approach the female and current guard whilst popping, leading to a guard switch. Our results provide new insights into the use of vocal signals during cooperative mate guarding between allied male dolphins.
Full citation: King SL, Allen SJ, Krützen M and Connor RC 2019. Vocal behaviour of allied male dolphins during cooperative mate guarding. Animal Cognition https://doi.org/10.1007/s10071-019-01290-1
Title: Multi-network-based diffusion analysis reveals vertical cultural transmission of sponge tool use within dolphin matrilines.
Authors: Wild S, Allen SJ, Krützen M, King SL, Gerber L, Hoppitt WJE.
Abstract: Behavioural differences among social groups can arise from differing ecological conditions, genetic predispositions and/or social learning. In the past, social learning has typically been inferred as responsible for the spread of behaviour by the exclusion of ecological and genetic factors. This ‘method of exclusion’ was used to infer that ‘sponging’, a foraging behaviour involving tool use in the bottlenose dolphin (Tursiops aduncus) population in Shark Bay, Western Australia, was socially transmitted. However, previous studies were limited in that they never fully accounted for alternative factors, and that social learning, ecology and genetics are not mutually exclusive in causing behavioural variation. Here, we quantified the importance of social learning on the diffusion of sponging, for the first time explicitly accounting for ecological and genetic factors, using a multi-network version of ‘network-based diffusion analysis’. Our results provide compelling support for previous findings that sponging is vertically socially transmitted from mother to (primarily female) offspring. This research illustrates the utility of social network analysis in elucidating the explanatory mechanisms behind the transmission of behaviour in wild animal populations.
Full citation: Wild S, Allen SJ, Krützen M, King SL, Gerber L, Hoppitt WJE. 2019 Multi-network-based diffusion analysis reveals vertical cultural transmission of sponge tool use within dolphin matrilines. Biol. Lett. 15: 20190227. http://dx.doi.org/10.1098/rsbl.2019.0227
Highlights: Diving into the behaviour of male dolphins that engage in tool-use for the first time and comparing them to non-tool-using males, we found that:
Please see full blog on our Shark Bay website: http://www.sharkbaydolphins.org/latest-news/
Title: Tool use and social homophily among male bottlenose dolphins.
Authors: Bizzozzero MR, Allen SJ, Gerber L, Wild S, King SL, Connor RC, Friedman WR, Wittwer S, Krützen M.
Abstract: Homophilous behaviour plays a central role in the formation of human friendships. Individuals form social ties with others that show similar phenotypic traits, independently of relatedness. Evidence of such homophily can be found in bottlenose dolphins (Tursiops aduncus) in Shark Bay, Western Australia, where females that use marine sponges as foraging tools often associate with other females that use sponges. ‘Sponging’ is a socially learned, time-consuming behaviour, transmitted from mother to calf. Previous research illustrated a strong female bias in adopting this technique. The lower propensity for males to engage in sponging may be due to its incompatibility with adult male-specific behaviours, particularly the formation of multi-level alliances. However, the link between sponging and male behaviour has never been formally tested. Here, we show that male spongers associated significantly more often with other male spongers irrespective of their level of relatedness. Male spongers spent significantly more time foraging, and less time resting and travelling, than did male non-spongers. Interestingly, we found no difference in time spent socializing. Our study provides novel insights into the relationship between tool use and activity budgets of male dolphins, and indicates social homophily in the second-order alliance composition of tool-using bottlenose dolphins.
Our 2019 field season has kicked off with PhD student @KathrynGHolmes1 project on the ontogeny of alliance formation in juvenile male dolphins. Our team will be here from May through November documenting dolphin alliance behaviour and we are looking forward to another exciting year of research in Shark Bay!