Rats will never be exterminated; we need to learn how to knock their numbers back without poisoning everything else in the food chain [“City rat infestation raises health concerns”, October 16-23]. Rat poison endangers children, pets, and wildlife, and poisoned rodents are killing our magnificent owls, hawks, and other predators.

There is a new product called Rat X on the market that only targets rodents. But poison is never the solution; rats will build up resistance within a few years anyway.

> Lisa Owens Viani