Interesting! I wonder if the relative shortness of the chameleon digestive tract would make it difficult to foster a sufficiently large population of commensal gut flora.Yes, sugar is present in all living things. Didn’t mean to imply that wasn’t the case. The bacterial metabolism angle is an interesting one, but if we are talking about fructose, it’s a simple sugar not a complex one. So there’s not too much more to breakdown compared to the well-described breakdown of complex carbs by microbes that you indicate. but maybe the microbes in chameleons do so with fructose and we just aren’t aware of it. And this still leaves us with the interesting issue that it seems veiled chameleons don’t have the fructose transporter homologous to humans and snakes itself. So if this were the case it might mean fructose breakdown is more reliant on microbes in chameleons than other organisms, which would be interesting. Perhaps sucrose is another sugar worth considering in addition to fructose.