Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals

Katsufumi Sato*, Kagari Aoki, Yuuki Y. Watanabe, Patrick J. O. Miller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)
4 Downloads (Pure)


Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.

Original languageEnglish
Article numbere2205
Number of pages5
JournalScientific Reports
Publication statusPublished - 16 Jul 2013


  • Energetic advantages
  • Stroking patterns
  • Elephant seals
  • Body density
  • Fish
  • Whales
  • Depth
  • Sink


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