Cantilever-like structures such as long necks and antennae of many organisms stabilize via circular, tapering structure.

References

"Organisms most often use beams that are circular (or elliptical) in cross section, and for these the common engineering handbooks…don't give such direct solutions. Denny (1988) faced the matter in admirably direct fashion. Some degree of taper, though, is virtually universal, for the branches of trees, for long necks and upheld tails, for archy's long, thin cockroach antennae as well as for the cat's whiskers of mehitabel (Marquis 1927)." (Vogel 2003:373)

Book
Comparative Biomechanics: Life's Physical World, Second EditionPrinceton University PressMay 26, 2017
Steven Vogel

Living System/s

Organism
PlantsPlantaeKingdom

Organism
TrochochaetidaeFamily