IDIOT’S GUIDES: SCIENCE MYSTERIES EXPLAINED
Why can’t birds taste chili peppers?
Unlike mammals, birds can gobble as many crazy hot chilies as they like, straight from
the bush. They simply don’t feel the burn. Why not, and why is the chili plant so selective
about whom it tortures?
Birds lack the taste receptors on their tongues to feel the burning sensation from chili. Humans do have
the receptors and can feel the pain. Lots of pain! But ironically, chili may have a medical role to play in pain
One of the fascinating things about the plants we
eat is that many of them contain toxins the plant
has spent millions of years evolving—just so ani-
mals like us won’t eat them!
Only humans seem to be perverse enough to
actively seek out plants that actually hurt us to eat.
Little does the poor chili realize, but the correct
amount of capsaicin (the chemical that makes the
burn) actually enhances the ﬂavor of carefully pre-
pared meals. But only because humans are crazy!
As anyone who has been naughty or unlucky
enough to be hit by capsicum spray will agree, cap-
saicin burns any tissue it comes into contact with.
The plant is deﬁnitely sending us a message: don’t
eat my fruit!
Birds don’t get that message. Their taste
buds don’t react to capsaicin. It simply doesn’t
register in their mouths, and so birds can hap-
pily eat chilies with no ill eects. Later, the bird
ﬂies o, poops out the seeds, and a new chili
plant germinates. Everybody wins!
We mammals, unlike birds, have a nasty
habit of chewing our food, and our powerful
back teeth grind up and destroy many seeds.
Chili plants evolved capsaicin in their seeds
to discourage mammals from eating the fruit.
Plants without capsaicin got munched by an-
cient herbivores and didn’t propagate as widely
or successfully as those with spicier seeds.
Humans have learned to love the burn of
a good chili. As far as we know, we’ve always
enjoyed spicy food. Part of the explanation may
have to do with the way the brain releases en-
dorphins as the burn of the capsaicin fades.