From Longman Dictionary of Contemporary Englishdumb animals/creaturesdumb animals/creaturesHBAused to talk about animals when you want to emphasize that humans often treat them badly and they cannot protect themselves → dumb
Examples from the Corpus
dumb animals/creatures• You don't have to look far to see these dumb creatures crawling across the branches of many organizations today.• Would that as many animal lovers were as quick to speak and defend dumb animals instead of staying silent as so many do.• We would become like dumb animals, oxen, or go crazy, and probably both. 