Fact: Birds can’t taste chilli.
Due to a quirk of biology a pigeon could wolf down your vindaloo while you whimper and sweat in the corner like a little girl.
This strange fact comes down to the fact that chillies are a fruit. Plants work exceptionally hard to produce fruit, so they don’t just give it away. It comes packaged with seeds which will pass through the animal and return to the world when that animal egests them (aka goes for a poo). That poo acts as fertiliser to help those seeds grow into the next generation.
However, not all poo was created equal. Birds have a rather simple digestive system, so chilli seeds pass through very quickly and aren’t damaged in the process, so they can still grow into new plants. Mammals, on the other hand, have a slower, more complicated digestive system including teeth and lots of stomach acid. Molars grind down seeds while stomach acid breaks them down and effectively kills them.
So the chilli plant developed an ingenious tactic to stop us pesky mammals stealing its fruit. It pumped capcaisin (the molecule that makes chillies taste ‘hot’) into its fruit. Birds don’t have the right receptors in their mouths to detect capcasin, so they can eat the fruit without feeling the pain. Mammals however do have the receptor, and so get put off from nibbling on the fruits of the chilli plant’s labours.
So the chilli burn is the plant’s defence mechanism to stop mammals wasting chilli seeds. Except humans covet the chilli plant precisely because of this burning sensation. It would seem the tactic has somewhat backfired.
Our digestive system doesn’t break down all seeds though – some are hardier than the weedy chilli. Sewage treatment plants are often surrounded by strawberry plants that have survived the gauntlet of the human digestive system. That might help explain why strawberries taste delicious instead of like fire.
‘Another one of Mr Shaunak’s Little Bites of Science’
Image under Creative Commons License