I am pleased to announce the publication of our recent work on communication in Shark Bay’s male alliances…
Citation: King SL, Friedman W, Allen SJ, Gerber L, Jensen F, Wittwer S, Connor RC, Krützen M 2018. Bottlenose dolphins retain individual vocal labels in multi-level alliances. Current Biology https://doi.org/10.1016/j.cub.2018.05.013.
Field methods at a glance: A trio of dolphins forages in the shallows near Peron Peninsula. The research team confirms their identity’s with photo-identification, records their vocalisations with a four-hydrophone array and obtains aerial video with either a helikite- or a drone-mounted HD video camera (photo: Simon J Allen).
Summary: Cooperation between allied individuals and groups is ubiquitous in human societies, and vocal communication is known to play a key role in facilitating such complex human behaviours. In fact, complex communication may be a feature of the kind of social cognition required for the formation of social alliances, facilitating both partner choice and the execution of coordinated behaviours. As such, a compelling avenue for investigation is what role flexible communication systems play in the formation and maintenance of cooperative partnerships in other alliance-forming animals. Male bottlenose dolphins in some populations form complex multi-level alliances, where individuals cooperate in the pursuit and defense of an important resource: access to females. These strong relationships can last for decades and are critical to each male’s reproductive success. Convergent vocal accommodation is used to signal social proximity to a partner or social group in many taxa, and it has long been thought that allied male dolphins also converge onto a shared signal to broadcast alliance identity. Here, we combine a decade of data on social interactions with dyadic relatedness estimates to show that male dolphins that form multi-level alliances in an open social network retain individual vocal labels that are distinct from those of their allies. Our results differ from earlier reports of signature whistle convergence among males that form stable alliance pairs. Instead, they suggest that individual vocal labels play a central role in the maintenance of differentiated relationships within complex nested alliances.
Figure 1 from the paper deftly illustrates the strength of social bonds between first- and second-order alliance partners, while the spectrograms display the whistle contours of each individual male dolphin (King et al. 2018). Note the differences between contours relative to the strength of particular social bonds.
Media: There was some very nice coverage from funders National Geographic (which you can view at: https://news.nationalgeographic.com/2018/06/dolphins-animals-courtship-friends/#), a great summary appeared in The Conversation (http://theconversation.com/male-dolphins-use-their-individual-names-to-build-a-complex-social-network-97780) and, 48 hours later, it’s pretty much everywhere!
The Shark Bay Dolphin Research Alliance have just returned from the Society for Marine Mammalogy's biennial conference on the biology of marine mammals, which was held in Halifax, Nova Scotia. We were out in force with 8 oral talks and 1 poster on our long-term work on the behaviour, ecology, genetics and vocal communication of the Shark Bay dolphin population. Go team!
The article can be found here
Photo Credit: Simon J Allen
We are pleased to announce our new paper entitled 'Multi-modal sexual displays in Australian humpback dolphins' has been published in Scientific Reports.
Abstract: Sexual displays enriched by object carrying serve to increase individual male fitness, yet are uncommon phenomena in the animal kingdom. While they have been documented in a variety of taxa, primarily birds, they are rare outside non-human mammals. Here, we document marine sponge presenting associated with visual and acoustic posturing found in several, geographically widespread populations of Australian humpback dolphins (Sousa sahulensis) over ten years of observation. Only adult males presented marine sponges, typically doing so in the presence of sexually mature females, although social groups predominantly consisted of mixed age and sex classes. Male humpback dolphins appear to be using sponges for signalling purposes in multi-modal sexual displays. Further, based on limited behavioural and genetic data, we hypothesise that pairs of adult male Sousa form at least temporary coalitions or alliances. The use of objects in sexual displays by non-human mammals is rare and, moreover, cooperation between males in the pursuit of an indivisible resource is an evolutionary hurdle relatively few species have overcome. These findings suggest a hitherto unrecognised level of social complexity in humpback dolphins.
The paper can be downloaded here
The team arrived in Monkey Mia on the 3rd June for a three month stint in the field; collecting data on the vocal behaviour of the Shark Bay male alliances. We have already seen lots of familiar fins, have observed our first consortships of the season and have recorded some great whistle exchanges (a priority for this year) - watch this space for more news as the season progresses!
I am pleased to announce that the National Geographic Society has awarded me with a research grant to support my 2017 field season in Shark Bay, Western Australia, for my project entitled “Machiavellian Males: the evolution of vocal strategies in a complex system of dolphin alliances”.
National Geographic Society Research Grants are given to bold people and transformative ideas in the fields of exploration, scientific research, conservation, education, and storytelling. By giving a grant, the National Geographic Society invites a scientist to join a passionate community of like-minded, global leaders, called the National Geographic Explorers.
Read more about National Geographic Society Research Grants
I'm pleased to announce the publication of our review paper entitled "Vocal matching: the what, the why and the how" in Biology Letters. In this review, we use cetaceans and songbirds to describe and clarify the term vocal matching as an interactive vocal behaviour.
The abstract is as follows: Over the years, vocal matching has progressed beyond being an interesting behavioural phenomenon to one that now has relevance to a wide range of fields. In this review, we use birds and cetaceans to explain what vocal matching is, why animals vocally match and how vocal matching can be identified. We show that while the functional aspects of vocal matching are similar, the contexts in which matching is used can differ between taxa. Whereas vocal matching in songbirds facilitates mate attraction and the immediate defence of resources, in parrots and cetaceans it plays a role in the maintenance of social bonds and the promotion of behavioural synchrony. We propose criteria for defining vocal matching with the aim of stimulating more matching studies across a wider range of taxa, including those using other, non-vocal, communication modalities. Finally, we encourage future studies to explore the importance of vocal learning in the development of vocal matching, and the information it may provide to third parties in the communication network.
You can download the article here: http://rsbl.royalsocietypublishing.org/content/12/10/20160666
The acoustic team have now finished their 2016 field season, have packed up in Monkey Mia and returned to Perth. It's been an unusual year in terms of the many windy days we have had - but when we have made it out on the water we have collected some excellent data. The males can be incredibly vocal and have entertained us with their vocal and physical displays. So far, we have collected acoustic data from 13 second-order alliances (approximately 85 males) and have documented over 30 consortships.
I will now spend the Australian summer analysing the data collected so far, which will not only help us identify which males we need to target next year and but also hopefully result in a paper or two!
Cooperation or dolphin ‘tug-of-war’? Comment on Kuczaj et al.and Eskelinen et al
Stephanie L. King, Simon J. Allen, Richard C. Connor & Kelly Jaakkola
Two recent papers by Kuczaj et al. (2015) and Eskelinen et al. (2016) claim to have demonstrated that (i) bottlenose dolphins (Tursiops truncatus) cooperated to solve a novel task and, (ii) vocal signals were important for coordinating these cooperative efforts. Although it is likely that bottlenose dolphins may share communicative signals in order to achieve a common goal, we suggest that this has not been demonstrated in the aforementioned studies. Here, we discuss the two main problems that preclude any definitive conclusions being drawn on cooperative task success and vocal communication from these studies. The first lies in the experimental design. The ‘cooperative task’, involving an apparatus that requires two dolphins to pull in opposite directions in order to achieve a food reward, is not conducive to cooperation, but could instead reflect a competitive ‘tug-of-war’. It is therefore of questionable use in distinguishing competitive from cooperative interactions. Second, the suggestion that the occurrence of burst-pulsed signals in this task was indicative of cooperation is disputable, as (i) this study could not determine which dolphins were actually producing the signals, and (ii) this sound-type is more commonly associated with aggressive signalling in dolphins. We commend the authors for investigating this exciting and topical area in animal communication and cognition, but the question of whether dolphins cooperate and communicate to solve a cooperative task remains as yet unanswered.
It was a quick trip back to Perth for me this week as I was presenting at the UWA Faculty of Science Rising Star Awards 2016 - where ten early career researchers (each nominated by their school) present their research in 3 minutes. It was a fantastic evening - showcasing the breadth of research across the faculty - and I was very happy to be representing the School of Animal Biology.