For the ancient world, don't forget the army of Xerxes, which according to Herodotus starved entire towns in Thrace and drank rivers dry. Not that Herodotus would exaggerate or anything....
Also, Alexander's army surely had some serious foraging requirements, being upwards of 20,000 men.
At some point, Xenophon's, Hannibal's, and Alexander's armies all resorted to eating pack animals.
Well I would have to say it all depend upon what land we are talking about. Each army of the ancient would were in different areas with different climates and different types of events. dontVoteBarack2016 stated that " Xenophon's, Hannibal's, and Alexander's armies all resorted to eating pack animals" which was true. But that's not quite living off the land. And if you think about it most armies don't really live off that land much. Lets start off with Ancient. I will use the Romans for this because I feel it is easiest and in my mind the idea "living off the land" . Historians have founded out that Roman Legions were every good at keep itself up to a fight. Or at least some Legions anyways. After the Marian Reforms each legionary was required to keep about 15 days worth of food and a waterskin. Now given that the reforms took place in 107 BC. I would say the Legion would be a little on the dangerous side of food and water. And at that time the Legion did well in clothing, arming, and fielding I would say their a bit weak in feeding. But taking into account that they had hunting training I would say there were the best for their. Medieval is a bit harder and I don't know much on it so I leave it be and let someone else take it. Modern is a bit more complex. You referred to things of the 19th and 20th century. I will agree with you that that the Zulu were the best at 'living off the land" But the British during the Anglo-Zulu Wars were a bit more modern in the arming, healing, and I say 50% of fielding but they did get cocky.. I'll bring it up a bit in time to the 21st century and say that if we had all the world's armies in this they would all and most likely tie. For the the simple reason of what we have today. Really we don't have to worry about much of the other requirement but feeding and clothing. Soldier carry about 5 to maybe 8 MREs in a standard pack for a patrol. They'd be screwed if they got into a two week siege or something of that nature. Their clothing at the coolest in the world. Plus they call on average 80 plus in gear. So you got to rest from time to time. I hope you found everything to your liking and if I answer your question. Im sorry if it so long.
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