Why Is a Swordfish’s Sword So Strong?

Turns out that remodeling–the same process used by mammals to repair bone–happens somewhat differently in rostral bone of marlin and swordfish (their “sword”).   In mammals, two different types of cells are responsible for strengthening damaged bone.  The swordfish, researchers discovered in a study of billfish bone remodeling, repairs bone without these two cells, but the result is much stronger, perhaps because the repairs were much smaller and made by a more complex process that is not fully understood yet by scientists.  From Proceedings of the National Academy of Sciences of the United States of America.