Rudy Giuliani and Bill de Blasio don’t agree on much. But when it comes to a mammal whose name derives from the Latin for “little thief,” they’ve both supported bans on New Yorkers letting these little guys into their homes.

We’re talking about ferrets, of course.

On Tuesday, the Board of Health considered a measure to repeal a ban on the critters, but it got only three of the six votes needed. Of the five who abstained, two were de Blasio appointees. Hizzoner said he was “comfortable with their judgment.”

This must have shocked ferret activists who have been outraged since 1999, when Giuliani’s Health Department banned ferrets as dangerous (sharp teeth), unhygienic and potentially feral.

Back then, Giuliani made headlines for a heated exchange with David Guthartz, president of New York Ferret’s Rights Advocacy.

Rudy told Guthartz his “excessive concern with little weasels” — “weasel” deemed a slur in the ferret community — is a “sickness” that required a “therapist.”

When asked about the Board of Health’s decision to reject the measure lifting the ferret ban, Guthartz said he wasn’t surprised.

And he said he wasn’t too keen about the bill anyway because it libeled ferrets even as it would have allowed New Yorkers to keep them as pets. “The bill called ferrets ‘vicious,’ ” said Guthartz. “We cannot have that out there.”

Giuliani, meanwhile, has mellowed and says he’d be fine with ferret legalization — if the Health Department and subsequent research is OK with it.

The state, meanwhile, allows ferrets as pets. Could the city’s decision on our furry friends be the start of another showdown between the mayor and the governor?