That doesn't hold true either Victor. The 158th was sent to Panama to train and to protect the canal zone, arriving on 2 January 1942. There were British and Indian units that had been fighting in the jungles since 08 Dec '41. By the time the 158th deployed to the pacific (arriving in Australia on 16 January 1943) There were a number of US units more experienced in jungle fighting than them, combat experience. The 1st and 2d marine Divisions had spent months fighting on Guadalcanal, the multiple Marine Raider battalions and Parachute battalions, the Army's 25th Infantry Division (27th, 35th, and 161st Regiments arrived in late 1942 but had trained intensively in Hawaii), the Americal Division (132d, 164th and 182d Regiments and had recieved fairly extensive weapons and jungle training during it's time in New Caledonia), the 164th in particular had established a very strong combat reputation. The Army's 32d Division had been fighting on New Guinea since September 1942, though they were ill trained and turned in a less than stellar performance, as much or more so, due to command and support issues as to failings within the ground combat element itself. There are a plethora of Australian units with vast amounts of jungle experience. As for martial arts, bayonet fighting and hand to hand combat training were a standard part of training well before the war and the "Bushmasters" were definately not unique or better trained in that area. Then as Terry stated earlier, there were British and Indian troops in the CBI with extensive jungle experience.
I stand corrected again......furthermore I understand I shouldn't say anything and will attempt to minimize my posts.