Every cat I have ever met absolutely loves the taste of human earwax; if you present them with a finger that you’ve just used to scratch the inside of your ear (bad idea, I know), they’ll lick it off with a good deal of gusto.
Have there been any theories advanced to why this is the case, or is this phenomenon unexplained?
This can give you a starting point:
The primary component of ear wax is keratin (derived from dead skin). Ear wax thus differs slightly from cerumen which is the secretory product of the ceruminous glands in the external auditory canal (Hawke, 2002).
Different individuals vary considerably in the amount and consistency of their ear wax. There are two types described, wet and dry, which are inherited. Dry wax is common in Asia, while wet wax is common in western Europe. Dry wax, also known as “rice-bran wax”, contains by weight about 20% lipid (fat). Oddly enough, rice-bran wax is associated with a lower incidence of breast cancer (Hawke, 2002).
Wet wax consists of approximately 50% lipid (Burkhart et al, 2000).
Cats do a lot of self licking, so it might benefit them to enjoy the taste of skin and skin products.