pubmed.ncbi.nlm.nih.gov

Energetic savings of bow-riding dolphins - PubMed

  • ️Mon Jan 01 2024

Energetic savings of bow-riding dolphins

Lorenzo Fiori et al. Sci Rep. 2024.

Abstract

Bow-riding occurs when dolphins swim in the pressure waves at the front of a vessel. Bow-riding is hypothesized to be "fun" for dolphins or to save them energy although the energetics have not been explored. An UAS (Unoccupied Aerial System) was used to follow and video-record adult dusky dolphins (Lagenorhynchus obscurus) bow-riding in front of a research vessel or free-swimming off Kaikoura, New Zealand. Videos of individual dolphins swimming in a linear direction at consistent speeds were analyzed with respiration rate used as a proxy for energy expenditure (bow riding n = 51; free-swimming n = 62). The respiration rates of bow-riding dolphins remained relatively constant across swimming speeds and were 45% lower than free-swimming dolphins at speeds exceeding 4 m/s, indicating substantial energetic savings. The respiration rates of free-swimming dolphins increased exponentially with speed, suggesting that dolphins incur comparatively high energetic expenditures from swimming rapidly. This research advances understanding of the biological function of bow-riding behavior and supports the energy saving hypothesis. Swimming energetics can be used to assess the impacts of anthropogenic disturbances to dolphin energy budgets.

Keywords: Anthropogenic interaction; Bow-riding; Dusky dolphins; Locomotion; Respiration; Unoccupied aerial system.

© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

PubMed Disclaimer

Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1

(a) Dolphins in bow-riding (D1) and not bow-riding (D0) positions. (b) The red angled line denotes the 90° area in front of the vessel where dolphins were considered bow-riding.

Fig. 2
Fig. 2

(a) Respiration rates of bow-riding (n = 27) and free-swimming (n = 27) dusky dolphins (Lagenorhynchus obscurus) travelling at the same speeds (2.2–6.6 m/s); Mean respiration rate was significantly lower for bow-riding dolphins (p < 0.001). (b) Respiration rates of bow-riding (n = 17) and free-swimming (n = 17) dusky dolphins (Lagenorhynchus obscurus) travelling at speeds > 4.0 m/s (4.3–6.6 m/s); Mean respiration rate was significantly lower for bow-riding dolphins (p < 0.001). Boxes represent first and third quartiles, solid horizontal lines inside boxes represent medians, crosses represent the mean, whiskers above and below boxes show 10th and 90th percentiles.

Fig. 3
Fig. 3

Respiration rate (breaths/min) as a function of swimming speed (0.9–6.9 m/s) for dusky dolphins (Lagenorhynchus obscurus). Black and white circles represent bow-riding (n = 62) and free-swimming (n = 51) dolphins, respectively. The dashed line represents the equation y = 4,48e0,0716x, which best describes the relationship between respiration rate and speed for bow-riding dolphins (R2 = 0.05). The solid black line represents the equation y = 2.71e0.279x, which best describes the relationship between respiration rate and speed for free-swimming dolphins (R2 = 0.82).

Fig. 4
Fig. 4

Respiration rates of dusky dolphins (Lagenorhynchus obscurus) bow-riding in group (n = 12; 2 to 4 individuals simultaneously) and individually (n = 12) travelling at the same speeds (2.6–5.4 m/s); Mean respiration rate did not differ significantly between the two contests (p = 0.315). Boxes represent first and third quartiles, solid horizontal lines inside boxes represent medians, crosses represent the mean, whiskers above and below boxes show 10th and 90th percentiles.

Similar articles

References

    1. Scholander, P. F. Wave-riding dolphins. Science130, 1658–1658. 10.1126/science.130.3389.1658.a (1959). - PubMed
    1. Williams, T. M. et al. Travel at low energetic cost by swimming and wave-riding bottlenose dolphins. Nature355, 821–823. 10.1017/S0952836902000298 (1992). - PubMed
    1. Hawkins, E. R. & Gartside, D. F. Interactive behaviours of bottlenose dolphins (Tursiops aduncus) during encounters with vessels. Aquat. Mamm.35, 259–268. 10.1578/AM.35.2.2009.259 (2009).
    1. Bose, N., Lien, J. & Lighthill, M. J. Energy absorption from ocean waves: A free ride for cetaceans. Proc. R. Soc. Lond. B Biol. Sci.240, 591–605. 10.1098/rspb.1990.0054 (1997). - PubMed
    1. O’Callaghan, S. A. & Massett, N. Short-beaked common dolphins (Delphinus delphis) observed bow-riding basking sharks (Cetorhinus maximus). Aquat. Mamm.46, 461–465. 10.1578/AM.46.5.2020.461 (2020).

MeSH terms

LinkOut - more resources