Optimization of swim depth across diverse taxa during horizontal travel

Semi-aquatic taxa, including humans, often swim at the air-water interface where they waste energy generating surface waves. For marine animals, theory predicts the most cost-efficient depth-use pattern for migrating, air-breathing species that do not feed in transit is to travel at around 2–3 times the depth of their body diameter, to minimise vertical distance travelled whilst avoiding wave drag close to the surface. This has rarely been examined, however, due to depth measurement resolution issues at the surface. Using satellite-relayed data for green turtles (Chelonia mydas), high-resolution depth-accelerometry and video data for little penguins (Eudyptula minor) and loggerhead turtles (Caretta caretta), and literature data for further sea turtle, penguin and whale species, we show that near-surface swimming is likely used broadly across non-foraging diving animals to minimise the cost of transport., See methods detailed in 'Optimization of swim depth across diverse taxa during horizontal travel' and Supporting Information. , , ReadMe file for data associated with the paper 'Optimization of swim depth across diverse taxa during horizontal travel'

K. L. Stokes, N. Esteban, P. Casale, A. Chiaradia, Y. Kaska, A. Kato, P. Luschi, Y. Ropert-Coudert, H. J. Stokes, G. C. Hays

[https://doi.org/10.5061/dryad.rn8pk0pks](https://doi.org/10.5061/dryad.rn8pk0pks)

The below lists files containing animal tracking data from the above publication

For dive summary data and comparative literature data see Tables S1–S3 in supplementary materials

'NA' indicates data is not relevant for that cell

1\. Green turtles (Chelonia mydas)

6x2022Cm_all_dives.txt

PTT: identifies the individual turtle

What: \"Dive\" - each row is an individual dive >= 5 m depth

Number: \"1\" - the number of dives detailed in the current row

Shape: \"Square\", \"V\" or \"U\" - describes the shape of the dive according to definition set by Wildlife Computers

Date: year/month/day (UTC)

Time: hours:minutes:seconds (UTC)

AveLat: the average latitude calcula...