The results showed:

• There is a U-shaped correlation between olfactory detection thresholds and carbon chain length of unbranched carboxylic acids, with decreasing thresholds from propanoic acid to butanoic acid, followed by an increase in thresholds from pentanoic acid to octanoic acid.
• The branching of the carbon backbone has an effect on detectability of pentanoic and hexanoic acids, but not on butanoic acids.
• A correlation between threshold values and the position of the methyl group attached to the carbon backbone of pentanoic acids.
• A comparison of the present data with those obtained in other species found no clear correlation between a species’ olfactory sensitivity and the size of its olfactory receptor repertoire.