Varts & Frevets of Gor
This research is done on the series of books written by John Norman, the comments in italics are mine and my point of view.
Woman of Gor
Varts

Perhaps I most dreaded those nights filled with the shrieks of the vart pack, a blind, batlike
swarm of flying rodents, each the size of a small dog. They could strip a carcass in a matter of
minutes, each carrying back some fluttering ribbon of flesh to the recesses of whatever dark cave
the swarm had chosen for its home. Moreover, some vart packs were rabid.

Frevets

"That is not an urt," said the proprietor. "They usually come out after dark. There is too much
nose and movement for them during the day." The small animal skittered backward, with a sound
of claws on the boards. Its eyes gleamed in the reflected light of the lamp. "Generally, too, they
do not come this high," said the proprietor. "That is a frevet." The frevet is a small, quick,
mammalian insectivore. "We have several in the house," he said. "They control the insects, the
beetles and lice and such."

Boabissia was silent.

"Not every insula furnishes frevets, said the proprietor."They are charming as well as useful
creatures. You will probably grow fond of them. You will probably wish to keep your door open at
night, for coolness, and to give access to them. They cannot gnaw through walls like urts, you
know." Mercenaries of Gor, page 276
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