To Susan, Ginko is mostly the guy who takes care of the animals. Not that it's a problem or anything - Susan thinks the animals here are pretty cool actually, and even though visiting the animals isn't even close to his job, he still probably goes to visit often, so he's at least passingly familiar with Ginko. Especially since his brother's job is performing with the animals so he's probably there a lot too.

Overall Ginko seems like a cool dude he thinks, and he's not at all bothered by him maybe not being the chattiest guy around or anything (he's way more personable than his brother is at least so he doesn't even think Ginko is weird at all or anything). He probably wouldn't go to him for any kind of deep conversation, but as a guy he can chat to and visit the animals, Susan likes him pretty well.