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...在地下巢穴中孵化的动物（如刚孵化的海龟幼崽）会消耗部分有限的能量储备，以挖掘穿过沙层或土层抵达地表。对于海龟而言，这一出巢过程可能需要幼崽花费3~7天。但由于难以观测地下发生的过程，我们对该过程的认知仍较为匮乏。本研究采用一种新颖的方法对掘洞行为进行表征：将加速度计（accelerometer）直接安装于刚孵化的绿海龟（Chelonia mydas）体表，记录其运动直至幼崽成功出巢。数据显示，被掩埋的幼崽始终保持头部朝上的朝向，但并未出现预期的伴随四肢交替爬行的左右摇摆运动。相反，它们通过背腹方向的起伏与俯仰运动移动，仿佛在沙层中垂直游动以抵达地表。运动活动呈现不规则且短暂的特征，其间穿插大量短暂的静止时段，多数静止时长不足10分钟。原文后续内容截断 # 数据来源：《沙中遨游：利用加速度计观测海龟幼崽隐秘的出巢前生命阶段》 https://doi.org/10.5061/dryad.c866t1gdd ## 数据集与文件结构说明 **动态身体加速度（Dynamic Body Acceleration, DBA）与结果汇总数据集** 本数据集的测量单位为加速度（g），经处理后得到动态身体加速度值（数据采集与分析的详细方法参见论文的方法部分与补充材料）。 本批CSV文件包含论文图2与图3中呈现的DBA验证数据及爬行运动数据。 文件名后缀代表加速度计的安装朝向：CU表示加速度计以背甲朝上的方向安装，HU表示加速度计以头部朝上的方向安装。 每个CSV文件内包含以下字段：（Time = 以秒为单位的时长；DBA_x、DBA_y、DBA_z = 对应x、y、z三轴的动态身体加速度值，原文后续内容截断）