Did American soldiers live in the jungle during WWII hiding from the Japanese?

My grandfather was a WWII veteran who was in the Pacific Theater. He claimed to have escaped captivity from the Japanese & to have lived in the jungle. He died in the 1960's so I was wondering if his story could possibly be true. The family story is that he escaped the Bataan Death March but I find that hard to believe judging from accounts I have read...but could have that have possible also?