Great clans of oxygen breathers also do it, now and then.

The strangers were oxygen breathers, they had indicated in Code.

Most of the other oxygen breathers he passed also wore filters.

Fact is, there we were, the great power among oxygen breathers in the known galaxy.

There was a sucking sound as the oxygen breathers in- haled.

In the remote past they had probably been oxygen breathers, and their life processes still depended on the element.

"Might be oxygen breathers, or why would they pick the M-type?"

They have to have some place to live, and I'll bet they're oxygen breathers.

That chlorine is deadly stuff to all us oxygen breathers.

"But if we don't go in there fast the oxygen breathers will die," the Colonel replied.