Lend us a paw!

At school now we are getting the students to prepare an end of term presentation of "great inventions". To get them thinking about it I gave them some pictures from the chindogu website and had them try to name and describe the invention in their own words. This particular picture elicited a Japanese expression I was unfamiliar with.

猫の手も借りたい　
neko no te mo karitai
wanting to borrow a cat's paw

Apparently this is used when really really busy so for example 猫の手も借りたいほど忙しい actually means "...so busy I need all the help I can get...". But why a cat in particular is singled out as the source of a helping hand (or paw) in times of need remains a mystery. I wouldn't be surprised if this expression was the inspiration behind these ingenious duster slippers for cats though.