Hey Catbird. Interesting question. I decided to try and research it and I found that A LOT of people are asking the same question you are. Many just laugh and assume their cat is a little on the crazy side (but come on, what cat isn't?
) . Someone even said as soon as she lets her cat out, he runs to where he knows the webs usually are and is licking his lips in anticipation. When looking up what webs of made of this is what I found:
"Spider's silk is made up of chains of amino acids. In other words, it is simply a protein (see How Food Works for details on amino acids and proteins). The two primary amino acids are glycine and alanine. "
I then went on to look up any connection between glycine/alanine and animals and found this summary of an experiment on rats and dogs:
The metabolic pathways of the deaminated residues of glycine and of alanine
have been compared indirectly by two different methods.
Absorbed from the intestine or peritoneum, alanine readily increases the
store of glycogen in the livers of fasting rats, whereas glycine does not do so.
When these amino-acids are fed to fasting dogs, alanine causes a smaller
rise in the catabolism of protein than glycine presumably because alanine but
not glycine forms sugar and so saves protein.
It is suggested, therefore, that the metabolic pathways of the deaminated
residues of alanine and of glycine are different."
Now as for bringing it all together for one easy to understand answer, who knows! Best I can make is that the cats are eating webs because either they NEED the extra protein amino acids, or maybe there is something on the web that just simply tastes yummy. The reason we eat something isn't always because we NEED it....do we NEED french fries? Nope....but they sure taste good.