swimming through sand: using accelerometers to observe the cryptic, pre-emergence life-stage of sea turtle hatchlings

Animals that hatch within a subterranean nest, such as turtle hatchlings, expend some of their limited energy reserves digging out through sand or soil to reach the surface. In sea turtles, this emergence process can take the hatchlings 3 – 7 days. However, we have a poor understanding of this process as it is difficult to observe what is occurring underground. Here we utilize a novel method to characterise digging-out behaviour: affixing an accelerometer directly to newly hatched green turtles (Chelonia mydas) to record movement until nest emergence. Our data revealed that buried hatchlings maintained a head-up orientation, but did not move in the expected left and right swaying motion associated with alternating limb crawling. Rather, they moved using dorsal-ventral heaving and pitching as if swimming vertically through the sand to the surface. Movement activity was irregular and brief, interspersed by many short periods of inactivity, mostly lasting less than 10 minutes. The first 24..., , , # Data from: swimming through sand: using accelerometers to observe the cryptic, pre-emergence life-stage of sea turtle hatchlings

[https://doi.org/10.5061/dryad.c866t1gdd](https://doi.org/10.5061/dryad.c866t1gdd)

## Description of the data and file structure

**Dynamic Body Acceleration (DBA) & Results Summary Data**

Units of measurement for the data are in acceleration (g) that have been processed into Dynamic body acceleration (See the article’s Methods and Supplementary Information for details on data collection and analysis).

These CSV files contain the DBA validation and crawling data represented in** (Fig. 2)** and** (Fig. 3)**.

File name suffixes represent the orientation of the accelerometer (CU = accelerometer oriented with carapace pointed upward, HU = accelerometer oriented with head pointed upward). 

Within each CSV file: (Time = duration in seconds & DBA_x*,* DBA_y*,* DBA_z = the Dynamic body acceleration values for each individual x, y and z axis respectivel...