Who knew this phrase was animal-related?
Yup, kinda self-explanatory. And we have good ol' language maven Richard Lederer to thank for this one too.
"When a cat is attacked by a dog or other animals," he writes, "it aggressively arches its back, a response that suggested the phrase to get one's back up to describe humans aroused into anger."
Source: Richard Lederer, host of "A Way With Words," on KPBS, San Diego Public Radio
Image courtesy Shoeboxblog.com. Used with permission.
(We'd appreciate your kind thoughts tomorrow, as Maxwell goes in to have his teeth cleaned...!)