CAREER: Investigating Fitness Trade-offs In A Southern Ocean Predator, The Leopard Seal

Baylor University, Waco TX

Investigators

Abstract

Trait differences between males and females are widespread across the animal kingdom. Because these traits often lead to trade-offs that affect reproductive success and survival, understanding them is a fundamental question in biology. Leopard seals are large predators in the Southern Ocean and an extreme example of female-biased size dimorphism in mammals, where females are the larger than males. This project will investigate the causes and consequences of the size differences in leopard seals and will generate new data on the life history, reproductive physiology, and breeding biology of this important and difficult to study polar predator. The information is critical for understanding leopard seals’ past, present, and future—from how the species evolved to predicting their resilience to environmental variation. The project also has a strong education component. It aims to increase polar biology research participation by training, mentoring, and supporting two postdocs, two grad students, and 25+ undergraduates. It will also engage students and the public in scientific research through outreach activities at local, national, and international scales. Trait differences can lead to important trade-offs that affect biological processes at multiple scales, from intraspecific differences in fitness to species-level life history strategies. Leopard seals exhibit an extreme form of female-biased size dimorphism. However, for solitary, wide-ranging polar species like leopard seals, it is difficult to study their life history and reproductive biology. As a result, it is unknown how leopard seals’ size dimorphism relates to other aspects of their biology. The goal of this project is to examine fitness trade-offs associated with female-biased dimorphism in leopard seals. Specifically, this study will (1) assess differences in male and female morphology and life history, (2) compare reproductive physiology between males and females, (3) investigate their breeding behavior and reproductive activities, and (4) conduct a cross-clade synthesis of female-biased dimorphism in mammals. The team will analyze existing specimens from biological collections and conduct field efforts to generate novel, complementary data. This information is critical for understanding how leopard seals evolved to survive and persist in the variable environment of the Southern Ocean. The research aligns with NSF’s Strategic Vision for Investments in Antarctic and Southern Ocean Research and supports ongoing efforts to create and utilize open polar research software, as well as data and sample reuse in polar research. This project relies on strong collaborations across academia, non-profits, and government institutions worldwide, and the results will be broadly shared with global audiences. As a CAREER award, this project has a strong polar education component that includes developing a research-intensive undergrad course (SEAL Lab) and providing graduate students and postdocs with hands-on leadership and mentoring experiences. The project will also engage students and the public in polar research, as students will conduct research in museum, field, and lab-based settings. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.