Myth: Violin strings were once made out of cat guts.

Violin strings were not made out of actual cat guts. Catgut is (and was) made from the walls of various animal intestines though. Generally sheep or goat intestines are preferred, but occasionally other intestines are used, such as intestines from pigs and cows. This practice of making strings and cord from animal intestines can be found going all the way back to the Ancient Egyptians, who revered cats, by the way. Both the Ancient Egyptians and catgut makers all the way up to today tend to prefer making these cords and strings from herbivorous, rather than carnivores, like cats.

So if catgut was never made from actual cat intestines, where did the name come from? One theory is that it came from “cattle-gut” and was eventually shortened down to just “catgut”. An equally plausible argument is that it derived from “kit-string” also known as “kit-gut”, a “kit” being a fiddle.

Another theory, which is probably dubious, is that makers of these strings in the 17th century chose the word to fool people into thinking the strings were actually made from catgut, thus, protecting their trade secrets.

Bonus Facts:

• Catgut strings are prepared by cleaning the intestines of fat and other undesirable additions. They do this by soaking the guts in water, then using a knife to scrape off the various things, such as fat, attached to the intestines. From there, the intestines are soaked in an alkaline substance and smoothed out. The surviving microbes on the catgut are then killed via sulfuric fumes. From there, the intestines are ready to be stretched/wound/etc. into appropriately sized strings.
• Animals that are quite lean tend to produce significantly higher quality strings than animals that poss large amounts of fat. This is one of the reasons pig gut isn’t typically preferred.
• Catgut isn’t just used for instruments, but is also often used in very high quality tennis rackets; bow-strings; for hanging weights on high-end clocks; and sometimes used for stitching wounds, though that practice has gradually given way to using cotton and synthetic threads, which seem to make wounds less prone to infection.