Shank's mare

I came across "shank's mare" in the book I finished yesterday, mentioned to two friends over dinner that I hadn't heard the phrase in years, and discovered neither of them (both well-read women) had ever heard of traveling by shank's mare.  They had no idea what I was talking about.  I looked up Merriam-Webster's definition just now to email it to them.

"A horse! a horse! my kingdom for a horse!"  Many travelers in centuries past would have agreed with King Richard's famous lines from Shakespeare's Richard III — when you needed to travel any distance in the days before automobiles, you definitely wanted a horse.  When one wasn't available, you had to rely on your built-in transportation equipment, your feet and legs.  The word "shank" has been used to mean "the lower leg" since before the 12th century, and "shank's mare" first appeared in writing in the late 1700s.  Another vivid expression connecting people and horses was "horse with ten toes," but that one is now relegated to history.

Merriam-Webster wanted to know why I looked up "shank's mare," so here's the quote from the book:

"I feel as if there are two Elspeths:  One who wears expensive, stylish clothes, travels in taxicabs, dines on duck, and goes across the country on a whim to meet handsome young Americans.  And the other, who wears broken-in homemade clothes, travels by shank's mare, dines on porridge, and goes across the country on a whim to meet handsome young Americans."
— found in Letters from Skye by Jessica Brockmole (2013), set in early 20th century Scotland (location 1563 in the un-paged Kindle edition)

Maybe knowing this unusual phrase confirms my Scottish (not Scotch) ancestry, but that's a word discussion for another day.  The difference between "Scottish" and "Scotch" also came up over dinner last night.