Dear colleagues,

My co-authors and I would like to share our recently published paper on odontocete whale body morphology and testing for possible linkages to life history:

Ferguson, Steven H., Jeff W. Higdon, Chloe Schmidt, Corinne Pomerleau, Cory J.D. Matthews. 2023. Investigating the Relationship Between Body Shape and Life History Traits in Toothed Whales: Can Body Shape Predict Fast-Slow Life Histories? Evolutionary Biology https://doi.org/10.1007/s11692-023-09605-4 or as a PDF here https://link.springer.com/content/pdf/10.1007/s11692-023-09605-4.pdf.

ABSTRACT: A widespread pattern in vertebrate life-history evolution is for species to evolve towards either fast or slow life histories;

however, the underlying causes of this pattern remain unclear. Toothed whales (Odontoceti) are a diverse group with a

range of body sizes and life histories, making them an ideal model to investigate potential drivers of this dichotomy. Using

ancestral reconstruction, we identified that certain groups of odontocetes evolved more-streamlined, presumably faster, body

shapes around the same time that killer whales (Orcinus orca) evolved into whale predators approximately 1 Mya during

the Pleistocene. This suggests that the evolution of a streamlined body shape may have been an adaptation to escape killer

whale predation, leading to longer life-history events. To test this hypothesis, we performed a cluster analysis of odontocete

whales and confirmed the dual pattern of life-history traits, with one group referred to as ‘reproducers’ characterized by early

age of maturity, short gestation, short interbirth interval, and short lifespan, and the other group referred to as ‘bet-hedgers’

exhibiting the opposite pattern. However, we found that life history grouping was relatively unrelated to whale shape (i.e.,

more streamlined or less streamlined). Therefore, we incorporated principal component results into mixed effects models, and

the model results indicated that body shape was positively related to neonate length (a measure of investment in progeny),

but not significantly related to the temporal life-history traits. Thus, whale body shape is not a sufficient explanation for the

evolution of fast-slow life histories in odontocete whales.

Please let me know if you'd like a PDF copy. Thanks,

Steven Ferguson, Fisheries and Oceans Canada, University of Manitoba: steve.ferguson@dfo-mpo.gc.ca