Pinkie and Brownie are a very small bug ferret family, which normally have between 8 to 30 married adults. Brownie is a cellular biotechnologist and Pinkie is an electrician. Pinkie is grouchy and protective with short patience for anyone other than Brownie. Brownie is prone to fretting and doing mothering behaviors to any sophont younger than them. Pinkie and Brownie are their English nicknames, because as with most bug ferrets their sign names can't be easily "transliterated."
Pinkie antisocial and easily overstimulated by ferret standards, and has been family-married several times, all ending in divorce. Brownie was the lone survivor of decompression disaster that left them in isolation for 6 days before rescue crews arrived, a harrowing experience. Brownie is prone to panic attacks in large groups of ferrets due to bad memories, but still has an intense need for constant social interaction typical of ferrets. Pinkie and Brownie are now inseparable partners, because they get just the right amount of interaction and company from one another.
They are ferry passengers on the Runaway later in the story, after working with Gillie and Idrisah on a language decoding project.
More art and comics of Pinkie and Brownie can be found in their tags on my tumblr blog.