There are no reasons to believe that humans are exceptional, they have all required enzymes (DDO, DAO).
golden ratio | Golden ratio | aspect ratio | Signal-to-noise ratio | Sharpe ratio | Receivables turnover ratio | Ratio Institute | ratio | MRC (Maximum Ratio Combining) | Monetae cudendae ratio | Maximal-ratio combining | Loan-to-value ratio | human sex ratio | Gear ratio | Fineness ratio | Digit ratio | Common-mode rejection ratio | Aspect ratio (wing) | Aspect ratio (image) | Aspect ratio |