How many in-game days take the coyotes in coyote's den or in goodspring cave to respawn?

I'm trying to beat the overkill challenge but I ran out of coyotes...


To beat that challenge you must kill any animal (not only coyotes but also ravens and dogs). But note that "Mutated animals do not count, only regular animals such as ravens, coyotes, and all types of dog, including NCR, Legion, and Fiend dogs.", as said in Fallout Wiki.