|MadSci Network: Evolution|
Dear Michael I've delayed replying because you have posed a really interesting question that I have been puzzling over for. I think there may be a third option to the two you suggest, or maybe it is part of your first answer, and that is that there are animals who do not recognize that the lemon is sour. In other words, they may not even detect the taste that we label as sourness. The problem is, I can find no evidence in support of this, at least with regard to lemons. However, birds do not seem to be affected by the capsaicin that makes chilli peppers hot, so there may be a precedent. Right now I don't have time to pursue this further but the Monell Chemical Senses Center is where I would go if I did. There's also the fact that most wild citrus fruits are pretty sour. Domestication seems to have added sweetness and maybe removed sourness, but something must have been eating all those wild citrus fruits. Jeremy p.s. If you are who I think you are, I'd be intrigued to know why you're thinking of lemons.
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