SOURCE: Star Man's Son (Ace Books 1952) aka Daybreak 2250 AD by Andre Norton

DESCRIPTION: "They were probably no taller than he but their emaciated bodies perched on stick legs made them seem to top him. The grayish skin which was stretched tight over their sharp bones was deep grained, almost scaly, and their bodies were bare save for strips of filthy tattered stuff worn about their loins. But their faces—! Fors forced himself to study, to study and file in memory what he saw. He tried to view those masks of borrow with detachment. In general outline they were remotely human. But the eyes deep set in bone-rimmed pits, the elongated jaws above which the nose was only two slits-jaws equipped with a hunting beast's fangs—sharp fangs never fully covered by thin vestiges of lips—those were not human. They were—he recoiled from the picture formed in his mind—they were rats!" (Star Man's Son by Andre Norton)

NOTES:  The Beast men are a race of cunningly wicked creatures inhabiting the old cities of Earth. high radiation from the nuclear war has changed them from men into monsters. There are rumors that they may have been experiments on splitting animal genes with human genes before the war. The beast men use guerilla warfare tactics and favor sneaky weapons like poisonous darts and ambushing travelers. They also have special rat wranglers that that carry hundreds of rats on their backs in cages. The rats are used for torture and other evil deeds. Beast man social organization is based on might. The beast men come out of their city in an attempt to wipe out and conquer the humans when one beast man is born with a larger brain. This genius is killed in a battle but wise men know others like him might appear in the future.

HISTORY: Norton's beast men are obviously inspired by H. G. Wells' beast men. Despite this her villains have a quality all their own and don't feel like an imitation. She imbues them with a cunning and evil logic that Wells' creatures don't have. (Except maybe the Hyena man.) She also does a great job of keeping them largely unseen until almost half way through the novel, building great suspense.