Wilderness Survival: A Warrior Foundational Skill
There is no military supremacy without self-sufficiency and associated resilience
Throughout history, one of the greatest challenges of any military leader has been logistics to maintain the troops hydrated, fed and relatively clean (lack of hygiene leading to disease outbreaks, and thus, potential disaster). Some basic military concepts, such as sieges or embargo, are also meant to bring enemies to their knees by essentially cutting off supply chains and starving them. Or simply psychologically breaking their men.
Guerrilla warfare, originally specific to irregular forces, but arguably also applicable to special forces facing a much larger and better armed enemy, is based on the ability to survive in the wilderness or other harsh and inhospitable environments, in near total self-sufficiency, and on the long-term.