Consequences of culturally-driven ecological specialization: Killer whales and beyond
The following paper has just been published: Consequences of culturally-driven ecological specialization: Killer whales and beyond. by: Hal Whitehead and John K.B. Ford Journal of Theoretical Biology 456: 279-294 Abstract: Culturally-transmitted ecological specialization occurs in killer whales, as well as other species. We hypothesize that some of the remarkable demographic and ecological attributes of killer whales result from this process. We formalize and model (using agent-based stochastic models parametrized using killer whale life history) the cultural evolution of specialization by social groups, in which a narrowing of niche breadth is spread and maintained in a group through social learning. We compare the demographic and ecological results of cultural specialization to those of a similar model of specialization through natural selection. We found that specialization, through either the cultural or natural selection routes, is adaptive in the short term with specialization often increasing fitness. Generalization, in contrast, is rarely adaptive. The cultural evolution of specialization can lead to increased rates of group extirpation. Specialization has little effect on group size but tends to reduce population size and resource abundance. While the two specialization processes produce similar results, cultural specialization can be very much faster. The results are generally consistent with what we know of the formation and maintenance of specialist ecotypes in killer whales, and have implications for the persistence, nature and ecological effects of these apex predators. You can read a .pdf at: http://whitelab.biology.dal.ca/labpub.htm Hal Whitehead Dalhousie University hwhitehe@dal.ca
The following paper, which has a considerable focus on cetaceans, has just been published: "The reach of gene–culture coevolution in animals" by: Hal Whitehead, Kevin Laland, Luke Rendell, Rose Thorogood and Andrew Whiten Nature Communications 10:2405 (2019) It is Open Access and available at: https://www-nature-com.ezproxy.library.dal.ca/articles/s41467-019-10293-y Abstract: Culture (behaviour based on socially transmitted information) is present in diverse animal species, yet how it interacts with genetic evolution remains largely unexplored. Here, we review the evidence for gene–culture coevolution in animals, especially birds, cetaceans and primates. We describe how culture can relax or intensify selection under different circumstances, create new selection pressures by changing ecology or behaviour, and favour adaptations, including in other species. Finally, we illustrate how, through culturally mediated migration and assortative mating, culture can shape population genetic structure and diversity. This evidence suggests strongly that animal culture plays an important evolutionary role, and we encourage explicit analyses of gene–culture coevolution in nature. Hal Whitehead, Dalhousie University
The correct URL for this open access paper is: https://www.nature.com/articles/s41467-019-10293-y Apologies Hal Whitehead The following paper, which has a considerable focus on cetaceans, has just been published: "The reach of gene–culture coevolution in animals" by: Hal Whitehead, Kevin Laland, Luke Rendell, Rose Thorogood and Andrew Whiten Nature Communications 10:2405 (2019) Abstract: Culture (behaviour based on socially transmitted information) is present in diverse animal species, yet how it interacts with genetic evolution remains largely unexplored. Here, we review the evidence for gene–culture coevolution in animals, especially birds, cetaceans and primates. We describe how culture can relax or intensify selection under different circumstances, create new selection pressures by changing ecology or behaviour, and favour adaptations, including in other species. Finally, we illustrate how, through culturally mediated migration and assortative mating, culture can shape population genetic structure and diversity. This evidence suggests strongly that animal culture plays an important evolutionary role, and we encourage explicit analyses of gene–culture coevolution in nature. Hal Whitehead, Dalhousie University _______________________________________________ MARMAM mailing list MARMAM@lists.uvic.ca https://lists.uvic.ca/mailman/listinfo/marmam
The following paper has just been published: Whitehead, H. 2020. Cultural specialization and genetic diversity: killer whales and beyond. Journal of Theoretical Biology 490: 110164. It is available at: https://authors.elsevier.com/a/1aUli57im5agj [before 20 March 2020] or: http://whitelab.biology.dal.ca/labpub.htm Abstract: Culturally-transmitted ecological specialization can reduce niche breadths with demographic and ecological consequences. I use agent-based models, grounded in killer whale biology, to investigate the potential consequences of cultural specialization for genetic diversity. In these models, cultural specialization typically reduces the number of mitochondrial haplotypes, mitochondrial haplotype diversity, mitochondrial nucleotide diversity, and heterozygosity at nuclear loci. The causal route of this decline is mostly indirect, being ascribed to a reduction in absolute population size resulting from cultural specialization. However, small group size exacerbates the decline in genetic diversity, presumably because of increased founder effects at the initiation of each cultural ecotype. These results are concordant with measures of low genetic diversity in the killer whale, although culturally-transmitted ecological specialization alone might not be sufficient to fully account for the species’ very low mitochondrial diversity. The process may also operate in other species. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
The following paper has just been published: Whitehead H, Smith TD, Rendell L. 2021 Adaptation of sperm whales to open-boat whalers: rapid social learning on a large scale? Biology Letters 17: 20210030. https://doi.org/10.1098/rsbl.2021.0030 It is available at: https://royalsocietypublishing.org/doi/10.1098/rsbl.2021.0030 or: http://whitelab.biology.dal.ca/hw/Response%20of%20whales%20to%20whaling%20Bi... Abstract: Animals can mitigate human threats, but how do they do this, and how fast can they adapt? Hunting sperm whales was a major 19th Century industry. Analysis of data from digitized logbooks of American whalers in the North Pacific found that the rate at which whalers succeeded in harpooning (striking) sighted whales fell by about 58% over the first few years of exploitation in a region. This decline cannot be explained by the earliest whalers being more competent, as their strike rates outside the North Pacific, where whaling had a longer history, were not elevated. The initial killing of particularly vulnerable individuals would not have produced the observed rapid decline in strike rate. It appears that whales swiftly learned effective defensive behaviour. Sperm whales live in kin-based social units. Our models show that social learning, in which naïve social units, when confronted by whalers, learned defensive measures from grouped social units with experience, could lead to the documented rapid decline in strike rate. This rapid, large-scale adoption of new behaviour enlarges our concept of the spatiotemporal dynamics of non-human culture. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
The following paper has just been published: Whitehead, H., and M. Shin. 2022. Current global population size, post-whaling trend and historical trajectory of sperm whales. Scientific Reports 12: 19468. It is open access and available at: https://doi.org/10.1038/s41598-022-24107-7 Abstract: The sperm whale lives in most deep ice-free waters of the globe. It was targeted during two periods of whaling peaking in the 1840’s and 1960’s. Using a habitat suitability model, we extrapolated estimates of abundance from visual and acoustic surveys to give a global estimate of 736,053 sperm whales (CV = 0.218) in 1993. Estimates of trends in the post-whaling era suggest that: whaling, by affecting the sex ratio and/or the social cohesion of females, reduced recovery rates well after whaling ceased; preferentially-targeted adult males show the best evidence of recovery, presumably due to recruitment from breeding populations; several decades post-whaling, sperm whale populations not facing much human impact are recovering slowly, but populations may be declining in areas with substantial anthropogenic footprint. A theta-logistic population model enhanced to simulate spatial structure and the non-removal impacts of whaling indicated a pre-whaling population of 1,949,698 (CV = 0.178) in 1710 being reduced by whaling, and then then recovering a little to about 844,761 (CV = 0.209) in 2022. There is much uncertainty about these numbers and trends. A larger population estimate than produced by a similar analysis in 2002 is principally due to a better assessment of ascertainment bias. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
The following paper has just been published: Whitehead, H., J.K.B. Ford and A.G. Horn. 2023. Using culturally transmitted behavior to help delineate conservation units for species at risk. Biological Conservation It is open access and available at: https://www.sciencedirect.com/science/article/pii/S0006320723003403 [https://ars.els-cdn.com/content/image/1-s2.0-S0006320723X0007X-cov150h.gif]<https://www.sciencedirect.com/science/article/pii/S0006320723003403> Using culturally transmitted behavior to help delineate conservation units for species at risk<https://www.sciencedirect.com/science/article/pii/S0006320723003403> Culture (information or behavior acquired by social learning and shared by members of a community) is an inheritance system that that can contribute t… www.sciencedirect.com Abstract: Culture (information or behavior acquired by social learning and shared by members of a community) is an inheritance system that that can contribute to the designation of conservation units for species at risk. The phenotypic diversity produced by culture is of intrinsic value and behaviorally-cohesive communities or sets of communities may be suitable candidate conservation units. This paper considers how cultural information can contribute to the designation of conservation units, in particular when assessing the discreteness and/or evolutionarily significance of potential units. Call and song dialects are particularly useful for documenting discreteness, while differences in seasonal migrations, if consistent, can be evolutionarily significant. Distinctions in foraging behavior or diet can suggest discreteness and/or evolutionary significance but it is important to show these are not environmentally driven. Social and play behavior can also be used to show discreteness. In some cases, it may not be clear whether behavioral differences are genetically or culturally determined but this may not matter for the delineation of conservation units if the behavioral distinctions are heritable. Genetic correlations can indicate the stability of culturally-determined behavior when transmission processes are parallel (e.g., mitochondrial DNA and behavior learned from the mother). The explicit use of cultural data in the delineation of conservation units is currently rare, but should increase as more detailed and extensive behavioral databases are compiled and analytical methods are developed. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
The following paper has just been published: Whitehead, H., 2024. Sperm whale clans and human societies. Royal Society Open Science It is open access and available at: https://royalsocietypublishing.org/doi/full/10.1098/rsos.231353 Abstract: Sperm whale society is structured into clans that are primarily distinguished by vocal dialects, which may be symbolic markers of clan identity. However, clans also differ in non-vocal behaviour. These distinctive behaviours, as well as clan membership itself, are learned socially, largely within matrilines. The clans can contain thousands of whales and span thousands of kilometres. Two or more clans typically use an area, but the whales only socialize with members of their own clan. In many respects the closest arallel may be the ethno-linguistic groups of humans. Patterns and processes of human prehistory that may be instructive in studying sperm whale clans include: the extreme variability of human societies; no clear link between modes of resource acquisition and social structure; that patterns of vocalizations may not map well onto other behavioural distinctions; and that interacting societies may deliberately distinguish their behaviour (schismogenesis). Conversely, while the two species and their societies are very different, the existence of very large-scale social structures in both sperm whales and humans supports some primary drivers of the phenomenon that are common to both species (such as cognition, cooperation, culture and mobility) and contraindicates others (e.g. tool-making and syntactic language). Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
We have recently published two papers on trends in cetacean abundance in an offshore MPA from a 35-year study. Some good news! Both papers are open access. Whitehead, H., and L.J. Feyrer. 2026. Thirty-five years of cetaceans in a canyon: patterns, shifts, and surprises in the Gully marine protected area. Marine Ecology Progress Series 776: meps15045 https://www.int-res.com/abstracts/meps/v776/meps15045 Abstract The Gully, a large submarine canyon on the edge of the Scotian Shelf, was made a marine protected area (MPA) in 2004. Together with 2 neighbouring smaller canyons, it has a particularly high density and diversity of cetaceans. We compiled sightings made from vessels during summer months between 1988 and 2023 to describe temporal and spatial trends of occurrence for 9 commonly sighted cetacean species in the Gully MPA and nearby waters. We looked for correlations between species as well as potential drivers of trends. Sighting rates increased for Sowerby’s beaked whales Mesoplodon biden and long-finned pilot whales Globicephala melas; decreased for humpback whales Megaptera novaeangliae, Atlantic white-sided dolphins Leucopleurus acutus, and striped dolphins Stenella coeruleoalba; while northern bottlenose Hyperoodon ampullatus and fin whales Balaenoptera physalus showed U-shaped trajectories. White-sided dolphins were more abundant in June, when water temperatures are cooler, whereas most of the other species showed a preference for the warmer months. Blue whales Balaenoptera musculus were most abundant with sea temperatures of ~18°C. The northern bottlenose whale is exceptional in that a large portion of the population is in the Gully at any time, there was no seasonal variation in sighting rates, and the inter-annual U-shaped trend can be linked with some confidence to reduced anthropogenic impact following the introduction of the MPA. For the other species, drivers are more speculative but include changes in relative resource abundance due to oceanographic and ecological processes, climate change, and variation in anthropogenic impacts. Feyrer, L., S.F. Walmsley, M.A. Stewart, M.A. MacNeil and H. Whitehead. 2025. Reversing decline: The impact of spatial conservation on endangered northern bottlenose whales. Journal of Applied Ecology 62: 2464-2474 Journal article<https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.70122> Abstract 1. Despite the end of commercial whaling in 1972, the northern bottlenose whale (Hyperoodon ampullatus) remains endangered in Canada and faces multiple human threats. The effectiveness of marine protected areas (MPAs) in safeguarding highly mobile species like these whales is still unclear. We examined 35 years (1988–2023) of population trends in the Gully submarine canyon, off Canada's east coast and assessed spatial changes in human activities within protected and unprotected habitat on the Scotian Shelf. 2. We analysed population size and habitat use using sighting rates and photo-identification mark-recapture data. We also evaluated whether spatial protections implemented through the designation of the Gully MPA in 2004 were associated with changes in the spatial distribution of threats, including ship strikes, entanglement, pollution and military sonar. 3. We found the northern bottlenose whale population declined from 1988 until the mid-2000s. However, from 2004 to 2010, coinciding with the establishment of spatial protections, this trend reversed, with the population growing near its maximum biological potential (~4% per year). 4. Our analysis indicates that the intensity of two serious threats—commercial fishing and vessel traffic—has decreased within the highly protected Zone 1 area of the Gully MPA, where approximately 42% of the population can be found at any time. However, these activities now occur relatively more often in important habitat areas outside the MPA, indicating a spatial shift in fishing effort that raises concerns about potential displacement effects. 5. Synthesis and applications. Spatial protection of the Gully MPA in 2004 coincided with a shift in human activities and the first signs of population recovery for northern bottlenose whales. While this suggests that well-designed MPAs can contribute to conservation outcomes even for highly mobile species, long-term success likely depends on continued monitoring and effective threat reduction both within the MPA and across other important habitats. Coordinated management across fisheries, shipping, offshore energy and defence sectors is essential. The Gully stands out as a rare conservation success in the open ocean, but its gains are not guaranteed. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca) Laura Feyrer, University of Manitoba (laura.joan@gmail.com)
We have recently published the following open access paper: Whitehead, H., C.M.K. Clarke and A. Eguiguren.2026. Sperm whales habituate to research vessels engaged in photoidentification. PLOS-ONE 21: e0348681. Journal article<https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0348681> Data<https://zenodo.org/records/20332000> Abstract Wildlife research has the potential to affect the subject animals. These effects can be problematic from ethical and management perspectives, as well as for the effectiveness of the research process itself. For individually-based behavioral research, repeated identifications are often necessary, which can lead to habituation or sensitization as animal responses to the researchers change over time because of learning. Sperm whales (Physeter macrocephalus) photoidentified off the Galápagos Islands became more tolerant of vessels engaged in photoidentification as they gained more experience of the vessels (as indicated by reductions in both the proportion of poor photographs taken and the range to the photographed whales). Thus, the whales habituated to the photoidentification process, making it more effective and suggesting little deleterious impact. Studies of habituation or sensitization should be carried out when wild animals are repeatedly exposed to disturbance from research activities. Hal Whitehead, Dalhousie University (hwhitehe@dal.ca)
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