Elephants develop wrinkles through both form and function

2024

Miscellaneous

hi

Elephant trunks have prominent folds and wrinkles from birth, but we have little information on how wrinkle patterns differ between elephant species and how elephant trunks and their wrinkles develop. We assessed wrinkle patterns in Asian (Elephas maximus) and African savanna (Loxodonta africana) elephants. We find that adult Asian elephants have more dorsal trunk wrinkles (~126) than African elephants (~83). In both species, we find more dorsal than ventral trunk wrinkles and a closer spacing of wrinkles in the distal than in the proximal trunk. We also observed slight (10%) differences in wrinkle numbers as a function of trunk-lateralization, suggesting the wrinkle-pattern is use-dependent. MicroCT imaging revealed that the outer elephant trunk skin has a relatively constant thickness, whereas the inner skin parts are thicker between folds than in folds. In both elephant species in early fetuses the trunk shows the greatest length growth of all body parts and the ventral trunk tip develops before the dorsal trunk finger. In development, trunk wrinkles are added in two distinct phases, an early exponential phase and a later, slower phase. We suggest that wrinkles improve the ability of trunk skin to bend, and that differential flexibility requirements might explain dorsoventral, proximal-distal, left-right side, and species differences in wrinkle distribution.

@misc{Kaufmann24-SICB-wrinkle,
  title = {Elephants develop wrinkles through both form and function},
  author = {Kaufmann, Lena and Schulz, Andrew and Reveyaz, Neomie and Ritter, Cindy and Hildebrandt, Thomas and Brecht, Michael},
  booktitle = {Society of Integrative and Comparative Biology},
  address = {Seattle, USA},
  month = jan,
  year = {2024},
  doi = {},
  month_numeric = {1}
}