Scientists Discover Mechanical Forces Behind Crocodile Head Scale Formation

New research reveals that crocodile head scales form through compressive skin folding during embryonic development, rather than genetic programming.

Crocodile head scales develop through mechanical processes, specifically compressive folding, rather than being dictated by genetics like most other vertebrate skin structures.
Researchers observed that the skin on a Nile crocodile embryo grows faster than the underlying tissue, leading to irregular folds that eventually form polygonal scales.
Experiments injecting embryos with Epidermal Growth Factor (EGF) confirmed that skin growth rate and stiffness are key factors in scale formation, with altered growth creating exaggerated patterns.
Advanced imaging techniques, such as light-sheet fluorescence microscopy, allowed scientists to map tissue growth and collagen fiber organization, enabling accurate computer simulations of scale development.
The findings suggest that variations in mechanical properties, rather than genetic changes, drive the diversity of head scale patterns across crocodilian species, offering new insights into evolutionary processes.