Compared to most humanoid species, Takarans have an unusual anatomy and physiology, with internal organs distributed much more evenly around their body, tissue-regeneration genes and very thick hides. This results in a very high resistance to injury. Takarans also have voluntary control over their physiology, enabling them to put a part of their body in stasis (to slow injury in specific areas and thereby reduce the overall effects of the injury), or to put their whole body in stasis to a point that resembled death.
In 2381, Takarans were not Federation members. When Lonnoc Kedair emigrated to the Federation in order to join Starfleet, she was surprised that other humanoid species were much more vulnerable than hers. (TNG episode: "Suspicions", ST - Destiny novel: Gods of Night)