Krogan are exceptionally hardy, having evolved in a crucible of lethal conditions and monstrous predators. 240-degree vision, normally a feature of prey animals, gives krogan a broad awareness of their environment and approaching enemies. Their tough hides can withstand stabbings and gunfire, and multiple redundant organs allow them to survive internal injuries. An electro-conductive secondary circulatory system, rather than a central nervous system, makes krogan almost impossible to paralyze, while the "hump" on their backs stores valuable water and fats.
The extremely high birth rate of krogan, a response to Tuchanka's harsh environment, once saw them overrun gentler worlds within a few decades. The genophage has reduced live births to a relative handful.
Krogan physiology is also highly resistant to radioactive or toxic environments. This allows them to live comfortably on planets hostile to other life. Initiative scientists have studied krogan cellular regeneration while developing first-in colonist radiation treatments.