I'll bet you're right (KMG) that your snakes got confused feeling what they thought (hoped) was the fur of their prey- snakes do recognize things by feel & I think their skin, even with scales, is sensitive enough to feel the difference.
(But that begs the question, why don't I get bit- with my long hair that my snakes are always tangling with? Maybe because there's a lot more "human scent" in my case, so they know it's not prey? But I'm just guessing...)
As you said, most snake bites are just quick little pin-pricks- over so fast, & a bit of bleeding that's of no real consequence. More startling to us than anything- not like the damage that bites from dogs & birds, or scratches from cats, can do- & happily snake bites don't tend to get infected either.