The phrase "crawled on fours" refers to someone or something moving on their hands and knees. There are several synonyms for this phrase, including "crept on all fours," "scuttled on hands and knees," "crawled on hands and knees," "scurried on hands and knees," and "shuffled on all fours." Each of these phrases conveys the same general idea of someone or something moving close to the ground in a quadrupedal fashion. Depending on the context, each of these synonyms may be more or less appropriate, so it is important to choose the one that best conveys the intended meaning.