But they don't seem to wish to kill entire species.

Your race seems to have some developed natural defenses because you can tolerate rems that would kill most other species.

You were never the kind who went in for killing or torturing intelligent species.

Concentrations of salt up to 20% are required to kill most species of unwanted bacteria.

Why is it acceptable to kill certain species and not others?

Under the revised law, anyone selling, breeding and killing endangered species will be subject to jail terms up to seven years.

At times, the winter water temperatures are too cold and, in the summer months, the water is too hot, killing certain species.

"Killing endangered species in order to save them doesn't seem that rational."

They are able to extract minerals from the rock that would kill other species.

There is the added benefit of killing other invasive species.