Elephants develop wrinkles through both form and function

Elephant trunks have folds and wrinkles, but we don’t know how wrinkles differ between elephant species and how trunks and their wrinkles develop. Adult Asian elephants have significantly more dorsal major trunk wrinkles (~126 ± 25 SD) than African elephants (~83 ± 13 SD). There are more dorsal than ventral major trunk wrinkles and there is a closer wrinkle spacing distally than proximally. Wrinkle numbers differed slightly as a function of trunk-lateralization. MicroCT-imaging revealed a relatively constant thickness of the outer elephant trunk skin, whereas the inner skin parts are thicker between folds than in folds. The trunk shows the greatest fetal length growth of elephant body parts. Trunk wrinkles are added in an early exponential phase, where wrinkles double every 20 days, and a later phase, where wrinkles are added slowly and at a faster rate in Asian compared to African elephants. We suggest wrinkles improve the ability of trunk skin to bend., The full methods section is included in both the manuscript and the supplement. , , # Data from: Elephants develop wrinkles through both form and function

[https://doi.org/10.5061/dryad.zkh1893g4](https://doi.org/10.5061/dryad.zkh1893g4)

## Description of the data and file structure

The data is included on two Excel files. For reading and understanding data all files are labeled with headers that indicate the specific figure/table that the data is used for.

The relationship between the two Excel files is separate as one of the files is from microCT data gathered and exported from ImageJ where the other Excel file is from elephant wrinkle counts and comparisons between African and Asian elephants as well as across different developmental stages.

### Files and variables

#### File: MicroCT\_AmpWaveData.xlsx

**Description:**  One Excel file contains (MicroCT Ampthe data gathered from ImageJ for the amplitude and wavelength data of the MicroCT scans of the baby African and Asian elephants included in the manuscript (shown in Figure 4 and plotted in Figure 5). On the ...