Hydrodynamic properties of fin whale flippers predict maximum rolling performance

Area of Science:

• Marine Biology
• Biomechanics
• Hydrodynamics

Background:

• Maneuverability is crucial for animal locomotion but poorly understood in cetaceans.
• Cetacean flippers are hypothesized to act as control surfaces for maneuvers, yet quantitative data are scarce.

Purpose of the Study:

• To quantitatively test the hypothesis that cetacean flippers generate lift for maneuvers.
• To develop and validate a hydrodynamic model for fin whale roll performance.

Main Methods:

• Constructed a simple hydrodynamic model to predict fin whale longitudinal-axis roll.
• Collected kinematic data from 27 free-swimming fin whales using on-board sensors.
• Compared model predictions with field data for roll velocity at various speeds and roll excursions.

Main Results:

• The hydrodynamic model accurately predicted fin whale roll velocity based on field data.
• Calculated roll velocity from kinematic data closely matched model predictions.
• Flipper lift appears sufficient to account for most observed fin whale rolls.

Conclusions:

• Flipper-generated lift is a primary driver of longitudinal-axis rolls in fin whales.
• The findings support the role of flippers as control surfaces in cetacean locomotion.
• This study provides quantitative evidence for the hydrodynamics of whale maneuvering.