The ontogeny of skeletal muscle adaptations that enable long deep dives in Weddell seals

Our objective was to determine the ontogenetic changes in the skeletal muscles of Weddell seals that transform a non‐diving pup into an elite diving adult. Muscle biopsies were collected from pups, juveniles and adults and analyzed for changes in fiber type, mitochondrial density, myoglobin concentrations, and aerobic, lipolytic and anaerobic enzyme activities. The fiber type results showed a decrease in type I fibers with a significant …